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How to start Syslog ( Syslog-ng ) on IBM AIX

Thursday, October 20th, 2022

Syslog-ng is a system logging application, which can be a replacement of the default syslog. With syslog-ng, the log messages can be sent in an ecrypted/secure channel to a remote server. If the central log server or the network connection becomes unavailable syslog-ng will store messages on the local hard disk.

The syslog-ng application automatically sends the stored messages to the server when the connection is reestablished, in the same order the messages were received. The disk buffer is persistent – no messages are lost even if syslog-ng is restarted. (Another possibility to send those messages to a secondary server.)

syslog-ng can filter log messages and select only the ones matching certain criteria, but it cannot interpret and analyze the meaning behind the messages. It can receive messages from files, remote hosts, and other sources, and these are sent to one or more destinations (files, remote hosts..),

It has a server – client model, here only syslog-ng client informations will be described (syslog-ng server has not been tested, only client, which were sending messages to a remote server (qradar).)

One missing feature of syslog-ng, that it cannot rotate logs by itself. For log rotation an external tool like logrotate needs to be used.

1. Install / Uninstall syslog-ng on AIX

1.1. Install syslog-ng on AIX

After downloading the syslog-ng installer package, we have 2 options
– run ./syslog-ng-<edition>-<version>-<OS>-<platform>.run script, or
– install as an rpm package: rpm -i syslog-ng-premium-edition-<version>-<OS>-<arch>.rpm

During install, the default syslogd will be replaced automatically by syslog-ng (no parallel operation is possible).

1.2. Uninstall syslog-ng on AIX

If the .run installer has been used: /opt/syslog-ng/bin/uninstall.sh (The uninstall script will automatically restore the syslog daemon used before installing syslog-ng.)
If the .rpm package has been used: rpm -e syslog-ng-premium-edition (with rpm, it does not restore the syslog daemon used before syslog-ng).

AIX is a custom and non-free OS if you had to deal with it you might might ponder how to stop / start syslog-ng.
The paths to binaries on AIX
The configuration is not universal, but represents the GEK server.

2. Set Automatic start of syslog-ng on AIX

Enable Start from /etc/tcpip:

start /opt/freeware/sbin/syslog-ng "$src_running"

3. Check syslog-ng configuration is correct

Configuration could be under separate locations but the most likely ones for syslog-ng.conf and license.txt files are located in the
/opt/syslog-ng/etc/ directory or /etc/syslog-ng depending on how it was configured on install time.

After changing tuning the configuration, it can be checked for errors:

# /opt/freeware/sbin/syslog-ng –syntax-only

Tags: AIX, configured, connection, default, hosts, How to, Install Uninstall, remote server, rpm, syslog
Posted in AIX, System Administration | No Comments »

How to monitor Haproxy Application server backends with Zabbix userparameter autodiscovery scripts

Friday, May 13th, 2022

Haproxy is doing quite a good job in High Availability tasks where traffic towards multiple backend servers has to be redirected based on the available one to sent data from the proxy to.

Lets say haproxy is configured to proxy traffic for App backend machine1 and App backend machine2.

Usually in companies people configure a monitoring like with Icinga or Zabbix / Grafana to keep track on the Application server is always up and running. Sometimes however due to network problems (like burned Network Switch / router or firewall misconfiguration) or even an IP duplicate it might happen that Application server seems to be reporting reachable from some monotoring tool on it but unreachable from Haproxy server -> App backend machine2 but reachable from App backend machine1. And even though haproxy will automatically switch on the traffic from backend machine2 to App machine1. It is a good idea to monitor and be aware that one of the backends is offline from the Haproxy host.
In this article I'll show you how this is possible by using 2 shell scripts and userparameter keys config through the autodiscovery zabbix legacy feature.
Assumably for the setup to work you will need to have as a minimum a Zabbix server installation of version 5.0 or higher.

1. Create the required haproxy_discovery.sh and haproxy_stats.sh scripts

You will have to install the two scripts under some location for example we can put it for more clearness under /etc/zabbix/scripts

[root@haproxy-server1 ]# mkdir /etc/zabbix/scripts

[root@haproxy-server1 scripts]# vim haproxy_discovery.sh
#!/bin/bash
#
# Get list of Frontends and Backends from HAPROXY
# Example: ./haproxy_discovery.sh [/var/lib/haproxy/stats] FRONTEND|BACKEND|SERVERS
# First argument is optional and should be used to set location of your HAPROXY socket
# Second argument is should be either FRONTEND, BACKEND or SERVERS, will default to FRONTEND if not set
#
# !! Make sure the user running this script has Read/Write permissions to that socket !!
#
## haproxy.cfg snippet
# global
# stats socket /var/lib/haproxy/stats mode 666 level admin

HAPROXY_SOCK=""/var/run/haproxy/haproxy.sock
[ -n “$1” ] && echo $1 | grep -q ^/ && HAPROXY_SOCK="$(echo $1 | tr -d '\040\011\012\015')"

if [[ “$1” =~ (25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?):[0-9]{1,5} ]];
then
HAPROXY_STATS_IP="$1"
QUERYING_METHOD="TCP"
fi

QUERYING_METHOD="${QUERYING_METHOD:-SOCKET}"

query_stats() {
if [[ ${QUERYING_METHOD} == “SOCKET” ]]; then
echo "show stat" | socat ${HAPROXY_SOCK} stdio 2>/dev/null
elif [[ ${QUERYING_METHOD} == “TCP” ]]; then
echo "show stat" | nc ${HAPROXY_STATS_IP//:/ } 2>/dev/null
fi
}

get_stats() {
echo "$(query_stats)" | grep -v "^#"
}

[ -n “$2” ] && shift 1
case $1 in
B*) END="BACKEND" ;;
F*) END="FRONTEND" ;;
S*)
for backend in $(get_stats | grep BACKEND | cut -d, -f1 | uniq); do
for server in $(get_stats | grep "^${backend}," | grep -v BACKEND | grep -v FRONTEND | cut -d, -f2); do
serverlist="$serverlist,\n"'\t\t{\n\t\t\t"{#BACKEND_NAME}":"'$backend'",\n\t\t\t"{#SERVER_NAME}":"'$server'"}'
done
done
echo -e '{\n\t"data":[\n’${serverlist#,}’]}'
exit 0
;;
*) END="FRONTEND" ;;
esac

for frontend in $(get_stats | grep "$END" | cut -d, -f1 | uniq); do
felist="$felist,\n"'\t\t{\n\t\t\t"{#'${END}'_NAME}":"'$frontend'"}'
done
echo -e '{\n\t"data":[\n’${felist#,}’]}'

[root@haproxy-server1 scripts]# vim haproxy_stats.sh
#!/bin/bash
set -o pipefail

if [[ “$1” = /* ]]
then
HAPROXY_SOCKET="$1"
shift 0
else
if [[ “$1” =~ (25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?):[0-9]{1,5} ]];
then
HAPROXY_STATS_IP="$1"
QUERYING_METHOD="TCP"
shift 1
fi
fi

pxname="$1"
svname="$2"
stat="$3"

DEBUG=${DEBUG:-0}
HAPROXY_SOCKET="${HAPROXY_SOCKET:-/var/run/haproxy/haproxy.sock}"
QUERYING_METHOD="${QUERYING_METHOD:-SOCKET}"
CACHE_STATS_FILEPATH="${CACHE_STATS_FILEPATH:-/var/tmp/haproxy_stats.cache}"
CACHE_STATS_EXPIRATION="${CACHE_STATS_EXPIRATION:-1}" # in minutes
CACHE_INFO_FILEPATH="${CACHE_INFO_FILEPATH:-/var/tmp/haproxy_info.cache}" ## unused
CACHE_INFO_EXPIRATION="${CACHE_INFO_EXPIRATION:-1}" # in minutes ## unused
GET_STATS=${GET_STATS:-1} # when you update stats cache outsise of the script
SOCAT_BIN="$(which socat)"
NC_BIN="$(which nc)"
FLOCK_BIN="$(which flock)"
FLOCK_WAIT=15 # maximum number of seconds that "flock" waits for acquiring a lock
FLOCK_SUFFIX='.lock'
CUR_TIMESTAMP="$(date '+%s')"

debug() {
[ “${DEBUG}” -eq 1 ] && echo "DEBUG: $@" >&2 || true
}

debug "SOCAT_BIN => $SOCAT_BIN"
debug "NC_BIN => $NC_BIN"
debug "FLOCK_BIN => $FLOCK_BIN"
debug "FLOCK_WAIT => $FLOCK_WAIT seconds"
debug "CACHE_FILEPATH => $CACHE_FILEPATH"
debug "CACHE_EXPIRATION => $CACHE_EXPIRATION minutes"
debug "HAPROXY_SOCKET => $HAPROXY_SOCKET"
debug "pxname => $pxname"
debug "svname => $svname"
debug "stat => $stat"

# check if socat is available in path
if [ “$GET_STATS” -eq 1 ] && [[ $QUERYING_METHOD == “SOCKET” && -z “$SOCAT_BIN” ]] || [[ $QUERYING_METHOD == “TCP” && -z “$NC_BIN” ]]
then
echo 'ERROR: cannot find socat binary'
exit 126
fi

# if we are getting stats:
# check if we can write to stats cache file, if it exists
# or cache file path, if it does not exist
# check if HAPROXY socket is writable
# if we are NOT getting stats:
# check if we can read the stats cache file
if [ “$GET_STATS” -eq 1 ]
then
if [ -e “$CACHE_FILEPATH” ] && [ ! -w “$CACHE_FILEPATH” ]
then
echo 'ERROR: stats cache file exists, but is not writable'
exit 126
elif [ ! -w ${CACHE_FILEPATH%/*} ]
then
echo 'ERROR: stats cache file path is not writable'
exit 126
fi
if [[ $QUERYING_METHOD == “SOCKET” && ! -w $HAPROXY_SOCKET ]]
then
echo "ERROR: haproxy socket is not writable"
exit 126
fi
elif [ ! -r “$CACHE_FILEPATH” ]
then
echo 'ERROR: cannot read stats cache file'
exit 126
fi

# index:name:default
MAP="
1:pxname:@
2:svname:@
3:qcur:9999999999
4:qmax:0
5:scur:9999999999
6:smax:0
7:slim:0
8:stot:@
9:bin:9999999999
10:bout:9999999999
11:dreq:9999999999
12:dresp:9999999999
13:ereq:9999999999
14:econ:9999999999
15:eresp:9999999999
16:wretr:9999999999
17:wredis:9999999999
18:status:UNK
19:weight:9999999999
20:act:9999999999
21:bck:9999999999
22:chkfail:9999999999
23:chkdown:9999999999
24:lastchg:9999999999
25:downtime:0
26:qlimit:0
27:pid:@
28:iid:@
29:sid:@
30:throttle:9999999999
31:lbtot:9999999999
32:tracked:9999999999
33:type:9999999999
34:rate:9999999999
35:rate_lim:@
36:rate_max:@
37:check_status:@
38:check_code:@
39:check_duration:9999999999
40:hrsp_1xx:@
41:hrsp_2xx:@
42:hrsp_3xx:@
43:hrsp_4xx:@
44:hrsp_5xx:@
45:hrsp_other:@
46:hanafail:@
47:req_rate:9999999999
48:req_rate_max:@
49:req_tot:9999999999
50:cli_abrt:9999999999
51:srv_abrt:9999999999
52:comp_in:0
53:comp_out:0
54:comp_byp:0
55:comp_rsp:0
56:lastsess:9999999999
57:last_chk:@
58:last_agt:@
59:qtime:0
60:ctime:0
61:rtime:0
62:ttime:0
"

_STAT=$(echo -e "$MAP" | grep :${stat}:)
_INDEX=${_STAT%%:*}
_DEFAULT=${_STAT##*:}

debug "_STAT => $_STAT"
debug "_INDEX => $_INDEX"
debug "_DEFAULT => $_DEFAULT"

# check if requested stat is supported
if [ -z “${_STAT}” ]
then
echo "ERROR: $stat is unsupported"
exit 127
fi

# method to retrieve data from haproxy stats
# usage:
# query_stats "show stat"
query_stats() {
if [[ ${QUERYING_METHOD} == “SOCKET” ]]; then
echo $1 | socat ${HAPROXY_SOCKET} stdio 2>/dev/null
elif [[ ${QUERYING_METHOD} == “TCP” ]]; then
echo $1 | nc ${HAPROXY_STATS_IP//:/ } 2>/dev/null
fi
}

# a generic cache management function, that relies on 'flock'
check_cache() {
local cache_type="${1}"
local cache_filepath="${2}"
local cache_expiration="${3}"
local cache_filemtime
cache_filemtime=$(stat -c '%Y' "${cache_filepath}" 2> /dev/null)
if [ $((cache_filemtime+60*cache_expiration)) -ge ${CUR_TIMESTAMP} ]
then
debug "${cache_type} file found, results are at most ${cache_expiration} minutes stale.."
elif "${FLOCK_BIN}" –exclusive –wait "${FLOCK_WAIT}" 200
then
cache_filemtime=$(stat -c '%Y' "${cache_filepath}" 2> /dev/null)
if [ $((cache_filemtime+60*cache_expiration)) -ge ${CUR_TIMESTAMP} ]
then
debug "${cache_type} file found, results have just been updated by another process.."
else
debug "no ${cache_type} file found, querying haproxy"
query_stats "show ${cache_type}" > "${cache_filepath}"
fi
fi 200> "${cache_filepath}${FLOCK_SUFFIX}"
}

# generate stats cache file if needed
get_stats() {
check_cache 'stat' "${CACHE_STATS_FILEPATH}" ${CACHE_STATS_EXPIRATION}
}

# generate info cache file
## unused at the moment
get_info() {
check_cache 'info' "${CACHE_INFO_FILEPATH}" ${CACHE_INFO_EXPIRATION}
}

# get requested stat from cache file using INDEX offset defined in MAP
# return default value if stat is ""
get() {
# $1: pxname/svname
local _res="$("${FLOCK_BIN}" –shared –wait "${FLOCK_WAIT}" "${CACHE_STATS_FILEPATH}${FLOCK_SUFFIX}" grep $1 "${CACHE_STATS_FILEPATH}")"
if [ -z “${_res}” ]
then
echo "ERROR: bad $pxname/$svname"
exit 127
fi
_res="$(echo $_res | cut -d, -f ${_INDEX})"
if [ -z “${_res}” ] && [[ “${_DEFAULT}” != “@” ]]
then
echo "${_DEFAULT}"
else
echo "${_res}"
fi
}

# not sure why we'd need to split on backslash
# left commented out as an example to override default get() method
# status() {
# get "^${pxname},${svnamem}," $stat | cut -d\ -f1
# }

# this allows for overriding default method of getting stats
# name a function by stat name for additional processing, custom returns, etc.
if type get_${stat} >/dev/null 2>&1
then
debug "found custom query function"
get_stats && get_${stat}
else
debug "using default get() method"
get_stats && get "^${pxname},${svname}," ${stat}
fi

! NB ! Substitute in the script /var/run/haproxy/haproxy.sock with your haproxy socket location

You can download the haproxy_stats.sh here and haproxy_discovery.sh here

2. Create the userparameter_haproxy_backend.conf

[root@haproxy-server1 zabbix_agentd.d]# cat userparameter_haproxy_backend.conf
#
# Discovery Rule
#

# HAProxy Frontend, Backend and Server Discovery rules
UserParameter=haproxy.list.discovery[*],sudo /etc/zabbix/scripts/haproxy_discovery.sh SERVER
UserParameter=haproxy.stats[*],sudo /etc/zabbix/scripts/haproxy_stats.sh $2 $3 $4

# support legacy way

UserParameter=haproxy.stat.downtime[*],sudo /etc/zabbix/scripts/haproxy_stats.sh $2 $3 downtime

UserParameter=haproxy.stat.status[*],sudo /etc/zabbix/scripts/haproxy_stats.sh $2 $3 status

UserParameter=haproxy.stat.last_chk[*],sudo /etc/zabbix/scripts/haproxy_stats.sh $2 $3 last_chk

3. Create new simple template for the Application backend Monitoring and link it to monitored host

create-configuration-template-backend-monitoring

create-template-backend-monitoring-macros

Go to Configuration -> Hosts (find the host) and Link the template to it

4. Restart Zabbix-agent, in while check autodiscovery data is in Zabbix Server

[root@haproxy-server1 ]# systemctl restart zabbix-agent

Check in zabbix the userparameter data arrives, it should not be required to add any Items or Triggers as autodiscovery zabbix feature should automatically create in the server what is required for the data regarding backends to be in.

To view data arrives go to Zabbix config menus:

Configuration -> Hosts -> Hosts: (lookup for the haproxy-server1 hostname)

The autodiscovery should have automatically created the following prototypes

Now if you look inside Latest Data for the Host you should find some information like:

HAProxy Backend [backend1] (3 Items)

HAProxy Server [backend-name_APP/server1]: Connection Response
2022-05-13 14:15:04           History

HAProxy Server [backend-name/server2]: Downtime (hh:mm:ss)
2022-05-13 14:13:57   20:30:42       History

HAProxy Server [bk_name-APP/server1]: Status
2022-05-13 14:14:25   Up (1)       Graph
       ccnrlb01   HAProxy Backend [bk_CCNR_QA_ZVT] (3 Items)

HAProxy Server [bk_name-APP3/server1]: Connection Response
2022-05-13 14:15:05           History

HAProxy Server [bk_name-APP3/server1]: Downtime (hh:mm:ss)
2022-05-13 14:14:00   20:55:20       History

HAProxy Server [bk_name-APP3/server2]: Status
2022-05-13 14:15:08   Up (1)

To make alerting in case if a backend is down which usually you would like only left thing is to configure an Action to deliver alerts to some email address.

Tags: admin, configured, esac, file, frontend, Haproxy Application, How to, index, information, Network Switch, scripts, servers, shell scripts, sid, Zabbix Server
Posted in Bash Scripting, System Optimization, Zabbix | No Comments »

Webserver farm behind Load Balancer Proxy or how to preserve incoming internet IP to local net IP Apache webservers by adding additional haproxy header with remoteip

Monday, April 18th, 2022

Having a Proxy server for Load Balancing is a common solutions to assure High Availability of Web Application service behind a proxy.
You can have for example 1 Apache HTTPD webservers serving traffic Actively on one Location (i.e. one city or Country) and 3 configured in the F5 LB or haproxy to silently keep up and wait for incoming connections as an (Active Failure) Backup solution.

Lets say the Webservers usually are set to have local class C IPs as 192.168.0.XXX or 10.10.10.XXX and living in isolated DMZed well firewalled LAN network and Haproxy is configured to receive traffic via a Internet IP 109.104.212.13 address and send the traffic in mode tcp via a NATTed connection (e.g. due to the network address translation the source IP of the incoming connections from Intenet clients appears as the NATTed IP 192.168.1.50.

The result is that all incoming connections from haproxy -> webservers will be logged in Webservers /var/log/apache2/access.log wrongly as incoming from source IP: 192.168.1.50, meaning all the information on the source Internet Real IP gets lost.

How to pass Real (Internet) Source IPs from Haproxy "mode tcp" to Local LAN Webservers ?

Usually the normal way to work around this with Apache Reverse Proxies configured is to use HTTP_X_FORWARDED_FOR variable in haproxy when using HTTP traffic application that is proxied (.e.g haproxy.cfg has mode http configured), you have to add to listen listener_name directive or frontend Frontend_of_proxy

option forwardfor
option http-server-close

However unfortunately, IP Header preservation with X_FORWADED_FOR HTTP-Header is not possible when haproxy is configured to forward traffic using mode tcp.

Thus when you're forced to use mode tcp to completely pass any traffic incoming to Haproxy from itself to End side, the solution is to

Use mod_remoteip infamous module that is part of standard Apache installs both on apache2 installed from (.deb) package or httpd rpm (on redhats / centos).

1. Configure Haproxies to send received connects as send-proxy traffic

The idea is very simple all the received requests from outside clients to Haproxy are to be send via the haproxy to the webserver in a PROXY protocol string, this is done via send-proxy

send-proxy – send a PROXY protocol string

Rawly my current /etc/haproxy/haproxy.cfg looks like this:

global
        log /dev/log    local0
        log /dev/log    local1 notice
        chroot /var/lib/haproxy
        user haproxy
        group haproxy
        daemon
        maxconn 99999
        nbproc          1
        nbthread 2
        cpu-map         1 0
        cpu-map         2 1

defaults
        log     global
       mode    tcp

        timeout connect 5000
        timeout connect 30s
        timeout server 10s

    timeout queue 5s
    timeout tunnel 2m
    timeout client-fin 1s
    timeout server-fin 1s

                option forwardfor

    retries                 15

frontend http-in
                mode tcp

                option tcplog
        log global

                option logasap
                option forwardfor
                bind 109.104.212.130:80
    fullconn 20000
default_backend http-websrv
backend http-websrv
        balance source
                maxconn 3000

stick match src
    stick-table type ip size 200k expire 30m
        stick on src

        server ha1server-1 192.168.0.205:80 check send-proxy weight 254 backup
        server ha1server-2 192.168.1.15:80 check send-proxy weight 255
        server ha1server-3 192.168.2.30:80 check send-proxy weight 252 backup
        server ha1server-4 192.168.1.198:80 check send-proxy weight 253 backup
                server ha1server-5 192.168.0.1:80 maxconn 3000 check send-proxy weight 251 backup

frontend https-in
                mode tcp

          option tcplog
          log global

                option logasap
                option forwardfor
        maxconn 99999
       bind 109.104.212.130:443
        default_backend https-websrv
                backend https-websrv
        balance source
                maxconn 3000
        stick on src
    stick-table type ip size 200k expire 30m

                server ha1server-1 192.168.0.205:443 maxconn 8000 check send-proxy weight 254 backup
                server ha1server-2 192.168.1.15:443 maxconn 10000 check send-proxy weight 255
        server ha1server-3 192.168.2.30:443 maxconn 8000 check send-proxy weight 252 backup
        server ha1server-4 192.168.1.198:443 maxconn 10000 check send-proxy weight 253 backup
                server ha1server-5 192.168.0.1:443 maxconn 3000 check send-proxy weight 251 backup

listen stats
    mode http
    option httplog
    option http-server-close
    maxconn 10
    stats enable
    stats show-legends
    stats refresh 5s
    stats realm Haproxy\ Statistics
    stats admin if TRUE

After preparing your haproxy.cfg and reloading haproxy in /var/log/haproxy.log you should have the Real Source IPs logged in:

root@webserver:~# tail -n 10 /var/log/haproxy.log
Apr 15 22:47:34 pcfr_hware_local_ip haproxy[2914]: 159.223.65.16:58735 [15/Apr/2022:22:47:34.586] https-in https-websrv/ha1server-2 1/0/+0 +0 — 7/7/7/7/0 0/0
Apr 15 22:47:34 pcfr_hware_local_ip haproxy[2914]: 20.113.133.8:56405 [15/Apr/2022:22:47:34.744] https-in https-websrv/ha1server-2 1/0/+0 +0 — 7/7/7/7/0 0/0
Apr 15 22:47:35 pcfr_hware_local_ip haproxy[2914]: 54.36.148.248:15653 [15/Apr/2022:22:47:35.057] https-in https-websrv/ha1server-2 1/0/+0 +0 — 7/7/7/7/0 0/0
Apr 15 22:47:35 pcfr_hware_local_ip haproxy[2914]: 185.191.171.35:26564 [15/Apr/2022:22:47:35.071] https-in https-websrv/ha1server-2 1/0/+0 +0 — 8/8/8/8/0 0/0
Apr 15 22:47:35 pcfr_hware_local_ip haproxy[2914]: 213.183.53.58:42984 [15/Apr/2022:22:47:35.669] https-in https-websrv/ha1server-2 1/0/+0 +0 — 6/6/6/6/0 0/0
Apr 15 22:47:35 pcfr_hware_local_ip haproxy[2914]: 159.223.65.16:54006 [15/Apr/2022:22:47:35.703] https-in https-websrv/ha1server-2 1/0/+0 +0 — 7/7/7/7/0 0/0
Apr 15 22:47:36 pcfr_hware_local_ip haproxy[2914]: 192.241.113.203:30877 [15/Apr/2022:22:47:36.651] https-in https-websrv/ha1server-2 1/0/+0 +0 — 4/4/4/4/0 0/0
Apr 15 22:47:36 pcfr_hware_local_ip haproxy[2914]: 185.191.171.9:6776 [15/Apr/2022:22:47:36.683] https-in https-websrv/ha1server-2 1/0/+0 +0 — 5/5/5/5/0 0/0
Apr 15 22:47:36 pcfr_hware_local_ip haproxy[2914]: 159.223.65.16:64310 [15/Apr/2022:22:47:36.797] https-in https-websrv/ha1server-2 1/0/+0 +0 — 6/6/6/6/0 0/0
Apr 15 22:47:36 pcfr_hware_local_ip haproxy[2914]: 185.191.171.3:23364 [15/Apr/2022:22:47:36.834] https-in https-websrv/ha1server-2 1/1/+1 +0 — 7/7/7/7/0 0/0

2. Enable remoteip proxy protocol on Webservers

# a2enmod remoteip

On Debians, the command should produce a right symlink to mods-enabled/ directory

# ls -al /etc/apache2/mods-enabled/*remote*
lrwxrwxrwx 1 root root 31 Mar 30 2021 /etc/apache2/mods-enabled/remoteip.load -> ../mods-available/remoteip.load

3. Modify remoteip.conf file and allow IPs of haproxies or F5s

Configure RemoteIPTrustedProxy for every Source IP of haproxy to allow it to send X-Forwarded-For header to Apache,

Here are few examples, from my apache working config on Debian 11.2 (Bullseye):

webserver:~# cat remoteip.conf
RemoteIPHeader X-Forwarded-For
RemoteIPTrustedProxy 192.168.0.1
RemoteIPTrustedProxy 192.168.0.205
RemoteIPTrustedProxy 192.168.1.15
RemoteIPTrustedProxy 192.168.0.198
RemoteIPTrustedProxy 192.168.2.33
RemoteIPTrustedProxy 192.168.2.30
RemoteIPTrustedProxy 192.168.0.215
#RemoteIPTrustedProxy 51.89.232.41

On RedHat / Fedora other RPM based Linux distrubutions, you can do the same by including inside httpd.conf or virtualhost configuration something like:

<IfModule remoteip_module>
RemoteIPHeader X-Forwarded-For
RemoteIPInternalProxy 192.168.0.0/16
RemoteIPTrustedProxy 192.168.0.215/32
</IfModule>

4. Enable RemoteIP Proxy Protocol in apache2.conf / httpd.conf or Virtualhost custom config

Modify both haproxy / haproxies config as well as enable the RemoteIP module on Apache webservers (VirtualHosts if such used) and either in <VirtualHost> block or in main http config include:

RemoteIPProxyProtocol On

5. Change default configured Apache LogFormat

In Domain Vhost or apache2.conf / httpd.conf

Default logging Format will be something like:

LogFormat "%h %l %u %t \"%r\" %>s %O \"%{Referer}i\" \"%{User-Agent}i\"" combined

LogFormat "%v:%p %h %l %u %t \"%r\" %>s %O \"%{Referer}i\" \"%{User-Agent}i\"" combined

Once you find it in /etc/apache2/apache2.conf / httpd.conf or Vhost, you have to comment out this by adding shebang infont of sentence make it look as follows:

LogFormat "%v:%p %a %l %u %t \"%r\" %>s %O \"%{Referer}i\" \"%{User-Agent}i\"" vhost_combined
LogFormat "%a %l %u %t \"%r\" %>s %O \"%{Referer}i\" \"%{User-Agent}i\"" combined
LogFormat "%a %l %u %t \"%r\" %>s %O" common
LogFormat "%{Referer}i -> %U" referer
LogFormat "%{User-agent}i" agent

The Changed LogFormat instructs Apache to log the client IP as recorded by mod_remoteip (%a) rather than hostname (%h). For a full explanation of all the options check the official HTTP Server documentation page apache_mod_config on Custom Log Formats.

and reload each Apache server.

on Debian:

# apache2ctl -k reload

On CentOS

# systemctl restart httpd

6. Check proxy protocol is properly enabled on Apaches

remoteip module will enable Apache to expect a proxy connect header passed to it otherwise it will respond with Bad Request, because it will detect a plain HTML request instead of Proxy Protocol CONNECT, here is the usual telnet test to fetch the index.htm page.

root@webserver:~# telnet localhost 80
Trying 127.0.0.1…
Connected to localhost.
Escape character is '^]'.
GET / HTTP/1.1

HTTP/1.1 400 Bad Request
Date: Fri, 15 Apr 2022 19:04:51 GMT
Server: Apache/2.4.51 (Debian)
Content-Length: 312
Connection: close
Content-Type: text/html; charset=iso-8859-1

<!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML 2.0//EN">
<html><head>
<title>400 Bad Request</title>
</head><body>
<h1>Bad Request</h1>
<p>Your browser sent a request that this server could not understand.<br />
</p>
<hr>
<address>Apache/2.4.51 (Debian) Server at grafana.pc-freak.net Port 80</address>
</body></html>
Connection closed by foreign host.

root@webserver:~# telnet localhost 80
Trying 127.0.0.1…
Connected to localhost.
Escape character is '^]'.
HEAD / HTTP/1.1

HTTP/1.1 400 Bad Request
Date: Fri, 15 Apr 2022 19:05:07 GMT
Server: Apache/2.4.51 (Debian)
Connection: close
Content-Type: text/html; charset=iso-8859-1

Connection closed by foreign host.

To test it with telnet you can follow the Proxy CONNECT syntax and simulate you're connecting from a proxy server, like that:

root@webserver:~# telnet localhost 80
Trying 127.0.0.1…
Connected to localhost.
Escape character is '^]'.
CONNECT localhost:80 HTTP/1.0

HTTP/1.1 301 Moved Permanently
Date: Fri, 15 Apr 2022 19:13:38 GMT
Server: Apache/2.4.51 (Debian)
Location: https://zabbix.pc-freak.net
Cache-Control: max-age=900
Expires: Fri, 15 Apr 2022 19:28:38 GMT
Content-Length: 310
Connection: close
Content-Type: text/html; charset=iso-8859-1

<!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML 2.0//EN">
<html><head>
<title>301 Moved Permanently</title>
</head><body>
<h1>Moved Permanently</h1>
<p>The document has moved <a href="https://zabbix.pc-freak.net">here</a>.</p>
<hr>
<address>Apache/2.4.51 (Debian) Server at localhost Port 80</address>
</body></html>
Connection closed by foreign host.

You can test with curl simulating the proxy protocol CONNECT with:

root@webserver:~# curl –insecure –haproxy-protocol https://192.168.2.30

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta name="generator" content="pc-freak.net tidy">
<script src="https://ssl.google-analytics.com/urchin.js" type="text/javascript">
</script>
<script type="text/javascript">
_uacct = "UA-2102595-3";
urchinTracker();
</script>
<script type="text/javascript">
var gaJsHost = (("https:" == document.location.protocol) ? "https://ssl." : "http://");
document.write(unescape("%3Cscript src='" + gaJsHost + "google-analytics.com/ga.js' type='text/javascript'%3E%3C/script%3E"));
</script>
<script type="text/javascript">
try {
var pageTracker = _gat._getTracker("UA-2102595-6");
pageTracker._trackPageview();
} catch(err) {}
</script>

      –haproxy-protocol
              (HTTP) Send a HAProxy PROXY protocol v1 header at the beginning of the connection. This is used by some load balancers and reverse proxies
              to indicate the client's true IP address and port.

              This option is primarily useful when sending test requests to a service that expects this header.

              Added in 7.60.0.

7. Check apache log if remote Real Internet Source IPs are properly logged

root@webserver:~# tail -n 10 /var/log/apache2/access.log

213.183.53.58 – – [15/Apr/2022:22:18:59 +0300] "GET /proxy/browse.php?u=https%3A%2F%2Fsteamcommunity.com%2Fmarket%2Fitemordershistogram%3Fcountry HTTP/1.1" 200 12701 "https://www.pc-freak.net" "Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:98.0) Gecko/20100101 Firefox/98.0"
88.198.48.184 – – [15/Apr/2022:22:18:58 +0300] "GET /blog/iq-world-rank-country-smartest-nations/?cid=1330192 HTTP/1.1" 200 29574 "-" "Mozilla/5.0 (compatible; DataForSeoBot/1.0; +https://dataforseo.com/dataforseo-bot)"
213.183.53.58 – – [15/Apr/2022:22:19:00 +0300] "GET /proxy/browse.php?u=https%3A%2F%2Fsteamcommunity.com%2Fmarket%2Fitemordershistogram%3Fcountry
HTTP/1.1" 200 9080 "https://www.pc-freak.net" "Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:98.0) Gecko/20100101 Firefox/98.0"
159.223.65.16 – – [15/Apr/2022:22:19:01 +0300] "POST //blog//xmlrpc.php HTTP/1.1" 200 5477 "-" "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/89.0.4389.114 Safari/537.36"
159.223.65.16 – – [15/Apr/2022:22:19:02 +0300] "POST //blog//xmlrpc.php HTTP/1.1" 200 5477 "-" "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/89.0.4389.114 Safari/537.36"
213.91.190.233 – – [15/Apr/2022:22:19:02 +0300] "POST /blog/wp-admin/admin-ajax.php HTTP/1.1" 200 1243 "https://www.pc-freak.net/blog/wp-admin/post.php?post=16754&action=edit" "Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:89.0) Gecko/20100101 Firefox/89.0"
46.10.215.119 – – [15/Apr/2022:22:19:02 +0300] "GET /images/saint-Paul-and-Peter-holy-icon.jpg HTTP/1.1" 200 134501 "https://www.google.com/" "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/100.0.4896.75 Safari/537.36 Edg/100.0.1185.39"
185.191.171.42 – – [15/Apr/2022:22:19:03 +0300] "GET /index.html.latest/tutorials/tutorials/penguins/vestnik/penguins/faith/vestnik/ HTTP/1.1" 200 11684 "-" "Mozilla/5.0 (compatible; SemrushBot/7~bl; +http://www.semrush.com/bot.html)"

116.179.37.243 – – [15/Apr/2022:22:19:50 +0300] "GET /blog/wp-content/cookieconsent.min.js HTTP/1.1" 200 7625 "https://www.pc-freak.net/blog/how-to-disable-nginx-static-requests-access-log-logging/" "Mozilla/5.0 (compatible; Baiduspider-render/2.0; +http://www.baidu.com/search/spider.html)"
116.179.37.237 – – [15/Apr/2022:22:19:50 +0300] "GET /blog/wp-content/plugins/google-analytics-dashboard-for-wp/assets/js/frontend-gtag.min.js?ver=7.5.0 HTTP/1.1" 200 8898 "https://www.pc-freak.net/blog/how-to-disable-nginx-static-requests-access-log-logging/" "Mozilla/5.0 (compatible; Baiduspider-render/2.0; +http://www.baidu.com/search/spider.html)"

You see from above output remote Source IPs in green are properly logged, so haproxy Cluster is correctly forwarding connections passing on in the Haproxy generated Initial header the Real IP of its remote connect IPs.

Sum it up, What was done?

HTTP_X_FORWARD_FOR is impossible to set, when haproxy is used on mode tcp and all traffic is sent as received from TCP IPv4 / IPv6 Network stack, e.g. modifying any HTTP sent traffic inside the headers is not possible as this might break up the data.

Thus Haproxy was configured to send all its received data by sending initial proxy header with the X_FORWARDED usual Source IP data, then remoteip Apache module was used to make Apache receive and understand haproxy sent Header which contains the original Source IP via the send-proxy functionality and example was given on how to test the remoteip on Webserver is working correctly.

Finally you've seen how to check configured haproxy and webserver are able to send and receive the End Client data with the originator real source IP correctly and those Internet IP is properly logged inside both haproxy and apaches.

Tags: adding, apache2, blog, close, common, configured, Connected, Date Fri, Debian, Domain Vhost, Expires Fri, frontend, haproxy, Haproxy Statistics, header, How to, incoming connections, ip, Load Balancer Proxy, load balancing, network, network address translation, run, script, TRUE, wait
Posted in Apache, Haproxy, Linux, Web and CMS | 1 Comment »

Create Linux High Availability Load Balancer Cluster with Keepalived and Haproxy on Linux

Tuesday, March 15th, 2022

Configuring a Linux HA (High Availibiltiy) for an Application with Haproxy is already used across many Websites on the Internet and serious corporations that has a crucial infrastructure has long time
adopted and used keepalived to provide High Availability Application level Clustering.
Usually companies choose to use HA Clusters with Haproxy with Pacemaker and Corosync cluster tools.
However one common used alternative solution if you don't have the oportunity to bring up a High availability cluster with Pacemaker / Corosync / pcs (Pacemaker Configuration System) due to fact machines you need to configure the cluster on are not Physical but VMWare Virtual Machines which couldn't not have configured a separate Admin Lans and Heartbeat Lan as we usually do on a Pacemaker Cluster due to the fact the 5 Ethernet LAN Card Interfaces of the VMWare Hypervisor hosts are configured as a BOND (e.g. all the incoming traffic to the VMWare vSphere HV is received on one Virtual Bond interface).

I assume you have 2 separate vSphere Hypervisor Physical Machines in separate Racks and separate switches hosting the two VMs.
For the article, I'll call the two brand new brought Virtual Machines with some installation automation software such as Terraform or Ansible – vm-server1 and vm-server2 which would have configured some recent version of Linux.

In that scenario to have a High Avaiability for the VMs on Application level and assure at least one of the two is available at a time if one gets broken due toe malfunction of the HV, a Network connectivity issue, or because the VM OS has crashed.
Then one relatively easily solution is to use keepalived and configurea single High Availability Virtual IP (VIP) Address, i.e. 10.10.10.1, which would float among two VMs using keepalived so at a time at least one of the two VMs would be reachable on the Network.

haproxy_keepalived-vip-ip-diagram-linux

Having a VIP IP is quite a common solution in corporate world, as it makes it pretty easy to add F5 Load Balancer in front of the keepalived cluster setup to have a 3 Level of security isolation, which usually consists of:

1. Physical (access to the hardware or Virtualization hosts)
2. System Access (The mechanism to access the system login credetials users / passes, proxies, entry servers leading to DMZ-ed network)
3. Application Level (access to different programs behind L2 and data based on the specific identity of the individual user,
special Secondary UserID, Factor authentication, biometrics etc.)

1. Install keepalived and haproxy on machines

Depending on the type of Linux OS:

On both machines

[root@server1:~]# yum install -y keepalived haproxy
…

If you have to install keepalived / haproxy on Debian / Ubuntu and other Deb based Linux distros

[root@server1:~]# apt install keepalived haproxy –yes
…

2. Configure haproxy (haproxy.cfg) on both server1 and server2

Create some /etc/haproxy/haproxy.cfg configuration

[root@server1:~]# vim /etc/haproxy/haproxy.cfg

#———————————————————————
# Global settings
#———————————————————————
global
log 127.0.0.1 local6 debug
chroot /var/lib/haproxy
pidfile /run/haproxy.pid
stats socket /var/lib/haproxy/haproxy.sock mode 0600 level admin
maxconn 4000
user haproxy
group haproxy
daemon
#debug
#quiet

#———————————————————————
# common defaults that all the 'listen' and 'backend' sections will
# use if not designated in their block
#———————————————————————
defaults
mode tcp
log global
# option dontlognull
# option httpclose
# option httplog
# option forwardfor
option redispatch
option log-health-checks
timeout connect 10000 # default 10 second time out if a backend is not found
timeout client 300000
timeout server 300000
maxconn 60000
retries 3

#———————————————————————
# round robin balancing between the various backends
#———————————————————————

listen FRONTEND_APPNAME1
bind 10.10.10.1:15000
mode tcp
option tcplog
# #log global
log-format [%t]\ %ci:%cp\ %bi:%bp\ %b/%s:%sp\ %Tw/%Tc/%Tt\ %B\ %ts\ %ac/%fc/%bc/%sc/%rc\ %sq/%bq
balance roundrobin
timeout client 350000
timeout server 350000
timeout connect 35000
server app-server1 10.10.10.55:30000 weight 1 check port 68888
server app-server2 10.10.10.55:30000 weight 2 check port 68888

listen FRONTEND_APPNAME2
bind 10.10.10.1:15000
mode tcp
option tcplog
#log global
log-format [%t]\ %ci:%cp\ %bi:%bp\ %b/%s:%sp\ %Tw/%Tc/%Tt\ %B\ %ts\ %ac/%fc/%bc/%sc/%rc\ %sq/%bq
balance roundrobin
timeout client 350000
timeout server 350000
timeout connect 35000
server app-server1 10.10.10.55:30000 weight 5
server app-server2 10.10.10.55:30000 weight 5

You can get a copy of above haproxy.cfg configuration here.
Once configured roll it on.

[root@server1:~]# systemctl start haproxy
[root@server1:~]# ps -ef|grep -i hapro
root 285047 1 0 Mar07 ? 00:00:00 /usr/sbin/haproxy -Ws -f /etc/haproxy/haproxy.cfg -p /run/haproxy.pid
haproxy 285050 285047 0 Mar07 ? 00:00:26 /usr/sbin/haproxy -Ws -f /etc/haproxy/haproxy.cfg -p /run/haproxy.pid

Bring up the haproxy also on server2 machine, by placing same configuration and starting up the proxy.

[root@server1:~]# vim /etc/haproxy/haproxy.cfg
…

…

3. Configure keepalived on both servers

We'll be configuring 2 nodes with keepalived even though if necessery this can be easily extended and you can add more nodes.
First we make a copy of the original or existing server configuration keepalived.conf (just in case we need it later on or if you already had something other configured manually by someone – that could be so on inherited servers by other sysadmin)

[root@server1:~]# mv /etc/keepalived/keepalived.conf /etc/keepalived/keepalived.conf.orig
[root@server2:~]# mv /etc/keepalived/keepalived.conf /etc/keepalived/keepalived.conf.orig

a. Configure keepalived to serve as a MASTER Node

[root@server1:~]# vim /etc/keepalived/keepalived.conf

Master Node
global_defs {
router_id server1-fqdn # The hostname of this host.

enable_script_security
# Synchro of the state of the connections between the LBs on the eth0 interface
lvs_sync_daemon eth0

notification_email {
linuxadmin@notify-domain.com # Email address for notifications
}
notification_email_from keepalived@server1-fqdn # The from address for the notifications
smtp_server 127.0.0.1 # SMTP server address
smtp_connect_timeout 15
}

vrrp_script haproxy {
script "killall -0 haproxy"
interval 2
weight 2
user root
}

vrrp_instance LB_VIP_QA {
virtual_router_id 50
advert_int 1
priority 51

state MASTER
interface eth0
smtp_alert # Enable Notifications Via Email

authentication {
auth_type PASS
auth_pass testp141

}
### Commented because running on VM on VMWare
## unicast_src_ip 10.44.192.134 # Private IP address of master
## unicast_peer {
## 10.44.192.135 # Private IP address of the backup haproxy
## }

# }
# master node with higher priority preferred node for Virtual IP if both keepalived up
### priority 51
### state MASTER
### interface eth0
virtual_ipaddress {
10.10.10.1 dev eth0 # The virtual IP address that will be shared between MASTER and BACKUP
}
track_script {
haproxy
}
}

To dowload a copy of the Master keepalived.conf configuration click here

Below are few interesting configuration variables, worthy to mention few words on, most of them are obvious by their names but for more clarity I'll also give a list here with short description of each:

vrrp_instance – defines an individual instance of the VRRP protocol running on an interface.
state – defines the initial state that the instance should start in (i.e. MASTER / SLAVE )state –
interface – defines the interface that VRRP runs on.
virtual_router_id – should be unique value per Keepalived Node (otherwise slave master won't function properly)
priority – the advertised priority, the higher the priority the more important the respective configured keepalived node is.
advert_int – specifies the frequency that advertisements are sent at (1 second, in this case).
authentication – specifies the information necessary for servers participating in VRRP to authenticate with each other. In this case, a simple password is defined.
only the first eight (8) characters will be used as described in to note is Important thing
man keepalived.conf – keepalived.conf variables documentation !!! Nota Bene !!! – Password set on each node should match for nodes to be able to authenticate !
virtual_ipaddress – defines the IP addresses (there can be multiple) that VRRP is responsible for.
notification_email – the notification email to which Alerts will be send in case if keepalived on 1 node is stopped (e.g. the MASTER node switches from host 1 to 2)
notification_email_from – email address sender from where email will originte
! NB ! In order for notification_email to be working you need to have configured MTA or Mail Relay (set to local MTA) to another SMTP – e.g. have configured something like Postfix, Qmail or Postfix

b. Configure keepalived to serve as a SLAVE Node

[root@server1:~]# vim /etc/keepalived/keepalived.conf

#Slave keepalived
global_defs {
router_id server2-fqdn # The hostname of this host!

enable_script_security
# Synchro of the state of the connections between the LBs on the eth0 interface
lvs_sync_daemon eth0

notification_email {
linuxadmin@notify-host.com # Email address for notifications
}
notification_email_from keepalived@server2-fqdn # The from address for the notifications
smtp_server 127.0.0.1 # SMTP server address
smtp_connect_timeout 15
}

vrrp_script haproxy {
script "killall -0 haproxy"
interval 2
weight 2
user root
}

vrrp_instance LB_VIP_QA {
virtual_router_id 50
advert_int 1
priority 50

state BACKUP
interface eth0
smtp_alert # Enable Notifications Via Email

authentication {
auth_type PASS
auth_pass testp141
}
### Commented because running on VM on VMWare
## unicast_src_ip 10.10.192.135 # Private IP address of master
## unicast_peer {
## 10.10.192.134 # Private IP address of the backup haproxy
## }

### priority 50
### state BACKUP
### interface eth0
virtual_ipaddress {
10.10.10.1 dev eth0 # The virtual IP address that will be shared betwee MASTER and BACKUP.
}
track_script {
haproxy
}
}

Download the keepalived.conf slave config here

c. Set required sysctl parameters for haproxy to work as expected

[root@server1:~]# vim /etc/sysctl.conf
#Haproxy config
# haproxy
net.core.somaxconn=65535
net.ipv4.ip_local_port_range = 1024 65000
net.ipv4.ip_nonlocal_bind = 1
net.ipv4.tcp_tw_reuse = 1
net.ipv4.tcp_max_syn_backlog = 10240
net.ipv4.tcp_max_tw_buckets = 400000
net.ipv4.tcp_max_orphans = 60000
net.ipv4.tcp_synack_retries = 3

4. Test Keepalived keepalived.conf configuration syntax is OK

[root@server1:~]# keepalived –config-test
(/etc/keepalived/keepalived.conf: Line 7) Unknown keyword 'lvs_sync_daemon_interface'
(/etc/keepalived/keepalived.conf: Line 21) Unable to set default user for vrrp script haproxy – removing
(/etc/keepalived/keepalived.conf: Line 31) (LB_VIP_QA) Specifying lvs_sync_daemon_interface against a vrrp is deprecated.
(/etc/keepalived/keepalived.conf: Line 31) Please use global lvs_sync_daemon
(/etc/keepalived/keepalived.conf: Line 35) Truncating auth_pass to 8 characters
(/etc/keepalived/keepalived.conf: Line 50) (LB_VIP_QA) track script haproxy not found, ignoring…

I've experienced this error because first time I've configured keepalived, I did not mention the user with which the vrrp script haproxy should run,
in prior versions of keepalived, leaving the field empty did automatically assumed you have the user with which the vrrp script runs to be set to root
as of RHELs keepalived-2.1.5-6.el8.x86_64, i've been using however this is no longer so and thus in prior configuration as you can see I've
set the user in respective section to root.
The error Unknown keyword 'lvs_sync_daemon_interface' is also easily fixable by just substituting the lvs_sync_daemon_interface and lvs_sync_daemon and reloading
keepalived etc.

Once keepalived is started and you can see the process on both machines running in process list.

[root@server1:~]# ps -ef |grep -i keepalived
root 1190884 1 0 18:50 ? 00:00:00 /usr/sbin/keepalived -D
root 1190885 1190884 0 18:50 ? 00:00:00 /usr/sbin/keepalived -D

Next step is to check the keepalived statuses as well as /var/log/keepalived.log

If everything is configured as expected on both keepalived on first node you should see one is master and one is slave either in the status or the log

[root@server1:~]#systemctl restart keepalived

[root@server1:~]# systemctl status keepalived|grep -i state
Mar 14 18:59:02 server1-fqdn Keepalived_vrrp[1192003]: (LB_VIP_QA) Entering MASTER STATE

[root@server1:~]# systemctl status keepalived

● keepalived.service – LVS and VRRP High Availability Monitor
Loaded: loaded (/usr/lib/systemd/system/keepalived.service; enabled; vendor preset: disabled)
Active: inactive (dead) since Mon 2022-03-14 18:15:51 CET; 32min ago
Process: 1187587 ExecStart=/usr/sbin/keepalived $KEEPALIVED_OPTIONS (code=exited, status=0/SUCCESS)
Main PID: 1187589 (code=exited, status=0/SUCCESS)

Mar 14 18:15:04 server1lb-fqdn Keepalived_vrrp[1187590]: Sending gratuitous ARP on eth0 for 10.44.192.142
Mar 14 18:15:50 server1lb-fqdn systemd[1]: Stopping LVS and VRRP High Availability Monitor…
Mar 14 18:15:50 server1lb-fqdn Keepalived[1187589]: Stopping
Mar 14 18:15:50 server1lb-fqdn Keepalived_vrrp[1187590]: (LB_VIP_QA) sent 0 priority
Mar 14 18:15:50 server1lb-fqdn Keepalived_vrrp[1187590]: (LB_VIP_QA) removing VIPs.
Mar 14 18:15:51 server1lb-fqdn Keepalived_vrrp[1187590]: Stopped – used 0.002007 user time, 0.016303 system time
Mar 14 18:15:51 server1lb-fqdn Keepalived[1187589]: CPU usage (self/children) user: 0.000000/0.038715 system: 0.001061/0.166434
Mar 14 18:15:51 server1lb-fqdn Keepalived[1187589]: Stopped Keepalived v2.1.5 (07/13,2020)
Mar 14 18:15:51 server1lb-fqdn systemd[1]: keepalived.service: Succeeded.
Mar 14 18:15:51 server1lb-fqdn systemd[1]: Stopped LVS and VRRP High Availability Monitor

[root@server2:~]# systemctl status keepalived|grep -i state
Mar 14 18:59:02 server2-fqdn Keepalived_vrrp[297368]: (LB_VIP_QA) Entering BACKUP STATE

[root@server1:~]# grep -i state /var/log/keepalived.log
Mar 14 18:59:02 server1lb-fqdn Keepalived_vrrp[297368]: (LB_VIP_QA) Entering MASTER STATE

a. Fix Keepalived SECURITY VIOLATION – scripts are being executed but script_security not enabled.

When configurating keepalived for a first time we have faced the following strange error inside keepalived status inside keepalived.log

Feb 23 14:28:41 server1 Keepalived_vrrp[945478]: SECURITY VIOLATION – scripts are being executed but script_security not enabled.

To fix keepalived SECURITY VIOLATION error:

Add to /etc/keepalived/keepalived.conf on the keepalived node hosts
inside

global_defs {}

After chunk

enable_script_security

include

# Synchro of the state of the connections between the LBs on the eth0 interface
lvs_sync_daemon_interface eth0

5. Prepare rsyslog configuration and Inlcude additional keepalived options
to force keepalived log into /var/log/keepalived.log

To force keepalived log into /var/log/keepalived.log on RHEL 8 / CentOS and other Redhat Package Manager (RPM) Linux distributions

[root@server1:~]# vim /etc/rsyslog.d/48_keepalived.conf

#2022/02/02: HAProxy logs to local6, save the messages
local7.* /var/log/keepalived.log
if ($programname == 'Keepalived') then -/var/log/keepalived.log
if ($programname == 'Keepalived_vrrp') then -/var/log/keepalived.log
& stop

[root@server:~]# touch /var/log/keepalived.log

Reload rsyslog to load new config

[root@server:~]# systemctl restart rsyslog
[root@server:~]# systemctl status rsyslog

● rsyslog.service – System Logging Service
Loaded: loaded (/usr/lib/systemd/system/rsyslog.service; enabled; vendor preset: enabled)
Drop-In: /etc/systemd/system/rsyslog.service.d
└─rsyslog-service.conf
Active: active (running) since Mon 2022-03-07 13:34:38 CET; 1 weeks 0 days ago
Docs: man:rsyslogd(8)
https://www.rsyslog.com/doc/
Main PID: 269574 (rsyslogd)
Tasks: 6 (limit: 100914)
Memory: 5.1M
CGroup: /system.slice/rsyslog.service
└─269574 /usr/sbin/rsyslogd -n

Mar 15 08:15:16 server1lb-fqdn rsyslogd[269574]: — MARK —
Mar 15 08:35:16 server1lb-fqdn rsyslogd[269574]: — MARK —
Mar 15 08:55:16 server1lb-fqdn rsyslogd[269574]: — MARK —

If once keepalived is loaded but you still have no log written inside /var/log/keepalived.log

[root@server1:~]# vim /etc/sysconfig/keepalived
KEEPALIVED_OPTIONS="-D -S 7"

[root@server2:~]# vim /etc/sysconfig/keepalived
KEEPALIVED_OPTIONS="-D -S 7"

[root@server1:~]# systemctl restart keepalived.service
[root@server1:~]# systemctl status keepalived

● keepalived.service – LVS and VRRP High Availability Monitor
Loaded: loaded (/usr/lib/systemd/system/keepalived.service; enabled; vendor preset: disabled)
Active: active (running) since Thu 2022-02-24 12:12:20 CET; 2 weeks 4 days ago
Main PID: 1030501 (keepalived)
Tasks: 2 (limit: 100914)
Memory: 1.8M
CGroup: /system.slice/keepalived.service
├─1030501 /usr/sbin/keepalived -D
└─1030502 /usr/sbin/keepalived -D

Warning: Journal has been rotated since unit was started. Log output is incomplete or unavailable.

[root@server2:~]# systemctl restart keepalived.service
[root@server2:~]# systemctl status keepalived
…

6. Monitoring VRRP traffic of the two keepaliveds with tcpdump

Once both keepalived are up and running a good thing is to check the VRRP protocol traffic keeps fluently on both machines.
Keepalived VRRP keeps communicating over the TCP / IP Port 112 thus you can simply snoop TCP tracffic on its protocol.

[root@server1:~]# tcpdump proto 112

tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on eth0, link-type EN10MB (Ethernet), capture size 262144 bytes
11:08:07.356187 IP server1lb-fqdn > vrrp.mcast.net: VRRPv2, Advertisement, vrid 50, prio 53, authtype simple, intvl 1s, length 20
11:08:08.356297 IP server1lb-fqdn > vrrp.mcast.net: VRRPv2, Advertisement, vrid 50, prio 53, authtype simple, intvl 1s, length 20
11:08:09.356408 IP server1lb-fqdn > vrrp.mcast.net: VRRPv2, Advertisement, vrid 50, prio 53, authtype simple, intvl 1s, length 20
11:08:10.356511 IP server1lb-fqdn > vrrp.mcast.net: VRRPv2, Advertisement, vrid 50, prio 53, authtype simple, intvl 1s, length 20
11:08:11.356655 IP server1lb-fqdn > vrrp.mcast.net: VRRPv2, Advertisement, vrid 50, prio 53, authtype simple, intvl 1s, length 20

[root@server2:~]# tcpdump proto 112

tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on eth0, link-type EN10MB (Ethernet), capture size 262144 bytes
11:08:07.356187 IP server1lb-fqdn > vrrp.mcast.net: VRRPv2, Advertisement, vrid 50, prio 53, authtype simple, intvl 1s, length 20
11:08:08.356297 IP server1lb-fqdn > vrrp.mcast.net: VRRPv2, Advertisement, vrid 50, prio 53, authtype simple, intvl 1s, length 20
11:08:09.356408 IP server1lb-fqdn > vrrp.mcast.net: VRRPv2, Advertisement, vrid 50, prio 53, authtype simple, intvl 1s, length 20
11:08:10.356511 IP server1lb-fqdn > vrrp.mcast.net: VRRPv2, Advertisement, vrid 50, prio 53, authtype simple, intvl 1s, length 20
11:08:11.356655 IP server1lb-fqdn > vrrp.mcast.net: VRRPv2, Advertisement, vrid 50, prio 53, authtype simple, intvl 1s, length 20

As you can see the VRRP traffic on the network is originating only from server1lb-fqdn, this is so because host server1lb-fqdn is the keepalived configured master node.

It is possible to spoof the password configured to authenticate between two nodes, thus if you're bringing up keepalived service cluster make sure your security is tight at best the machines should be in a special local LAN DMZ, do not configure DMZ on the internet !!! 🙂 Or if you eventually decide to configure keepalived in between remote hosts, make sure you somehow use encrypted VPN or SSH tunnels to tunnel the VRRP traffic.

[root@server1:~]# tcpdump proto 112 -vv
tcpdump: listening on eth0, link-type EN10MB (Ethernet), capture size 262144 bytes
11:36:25.530772 IP (tos 0xc0, ttl 255, id 59838, offset 0, flags [none], proto VRRP (112), length 40)
server1lb-fqdn > vrrp.mcast.net: vrrp server1lb-fqdn > vrrp.mcast.net: VRRPv2, Advertisement, vrid 50, prio 53, authtype simple, intvl 1s, length 20, addrs: VIPIP_QA auth "testp431"
11:36:26.530874 IP (tos 0xc0, ttl 255, id 59839, offset 0, flags [none], proto VRRP (112), length 40)
server1lb-fqdn > vrrp.mcast.net: vrrp server1lb-fqdn > vrrp.mcast.net: VRRPv2, Advertisement, vrid 50, prio 53, authtype simple, intvl 1s, length 20, addrs: VIPIP_QA auth "testp431"

Lets also check what floating IP is configured on the machines:

[root@server1:~]# ip -brief address show
lo UNKNOWN 127.0.0.1/8
eth0 UP 10.10.10.5/26 10.10.10.1/32

The 10.10.10.5 IP is the main IP set on LAN interface eth0, 10.10.10.1 is the floating IP which as you can see is currently set by keepalived to listen on first node.

[root@server2:~]# ip -brief address show |grep -i 10.10.10.1

An empty output is returned as floating IP is currently configured on server1

To double assure ourselves the IP is assigned on correct machine, lets ping it and check the IP assigned MAC currently belongs to which machine.

[root@server2:~]# ping 10.10.10.1
PING 10.10.10.1 (10.10.10.1) 56(84) bytes of data.
64 bytes from 10.10.10.1: icmp_seq=1 ttl=64 time=0.526 ms
^C
— 10.10.10.1 ping statistics —
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 0.526/0.526/0.526/0.000 ms
[root@server2:~]# arp -an |grep -i 10.44.192.142
? (10.10.10.1) at 00:48:54:91:83:7d [ether] on eth0
[root@server2:~]# ip a s|grep -i 00:48:54:91:83:7d
[root@server2:~]#

As you can see from below output MAC is not found in configured IPs on server2.

[root@server1-fqdn:~]# /sbin/ip a s|grep -i 00:48:54:91:83:7d -B1 -A1
eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP group default qlen 1000
link/ether 00:48:54:91:83:7d brd ff:ff:ff:ff:ff:ff
inet 10.10.10.1/26 brd 10.10.1.191 scope global noprefixroute eth0

Pretty much expected MAC is on keepalived node server1.

7. Testing keepalived on server1 and server2 maachines VIP floating IP really works

To test the overall configuration just created, you should stop keeaplived on the Master node and in meantime keep an eye on Slave node (server2), whether it can figure out the Master node is gone and switch its
state BACKUP to save MASTER. By changing the secondary (Slave) keepalived to master the floating IP: 10.10.10.1 will be brought up by the scripts on server2.

Lets assume that something went wrong with server1 VM host, for example the machine crashed due to service overload, DDoS or simply a kernel bug or whatever reason.
To simulate that we simply have to stop keepalived, then the broadcasted information on VRRP TCP/IP proto port 112 will be no longer available and keepalived on node server2, once
unable to communicate to server1 should chnage itself to state MASTER.

[root@server1:~]# systemctl stop keepalived
[root@server1:~]# systemctl status keepalived
● keepalived.service – LVS and VRRP High Availability Monitor
Loaded: loaded (/usr/lib/systemd/system/keepalived.service; enabled; vendor preset: disabled)
Active: inactive (dead) since Tue 2022-03-15 12:11:33 CET; 3s ago
Process: 1192001 ExecStart=/usr/sbin/keepalived $KEEPALIVED_OPTIONS (code=exited, status=0/SUCCESS)
Main PID: 1192002 (code=exited, status=0/SUCCESS)

Mar 14 18:59:07 server1lb-fqdn Keepalived_vrrp[1192003]: Sending gratuitous ARP on eth0 for 10.10.10.1
Mar 15 12:11:32 server1lb-fqdn systemd[1]: Stopping LVS and VRRP High Availability Monitor…
Mar 15 12:11:32 server1lb-fqdn Keepalived[1192002]: Stopping
Mar 15 12:11:32 server1lb-fqdn Keepalived_vrrp[1192003]: (LB_VIP_QA) sent 0 priority
Mar 15 12:11:32 server1lb-fqdn Keepalived_vrrp[1192003]: (LB_VIP_QA) removing VIPs.
Mar 15 12:11:33 server1lb-fqdn Keepalived_vrrp[1192003]: Stopped – used 2.145252 user time, 15.513454 system time
Mar 15 12:11:33 server1lb-fqdn Keepalived[1192002]: CPU usage (self/children) user: 0.000000/44.555362 system: 0.001151/170.118126
Mar 15 12:11:33 server1lb-fqdn Keepalived[1192002]: Stopped Keepalived v2.1.5 (07/13,2020)
Mar 15 12:11:33 server1lb-fqdn systemd[1]: keepalived.service: Succeeded.
Mar 15 12:11:33 server1lb-fqdn systemd[1]: Stopped LVS and VRRP High Availability Monitor.

On keepalived off, you will get also a notification Email on the Receipt Email configured from keepalived.conf from the working keepalived node with a simple message like:

=> VRRP Instance is no longer owning VRRP VIPs <=

Once keepalived is back up you will get another notification like:

=> VRRP Instance is now owning VRRP VIPs <=

[root@server2:~]# systemctl status keepalived
● keepalived.service – LVS and VRRP High Availability Monitor
Loaded: loaded (/usr/lib/systemd/system/keepalived.service; enabled; vendor preset: disabled)
Active: active (running) since Mon 2022-03-14 18:13:52 CET; 17h ago
Process: 297366 ExecStart=/usr/sbin/keepalived $KEEPALIVED_OPTIONS (code=exited, status=0/SUCCESS)
Main PID: 297367 (keepalived)
Tasks: 2 (limit: 100914)
Memory: 2.1M
CGroup: /system.slice/keepalived.service
├─297367 /usr/sbin/keepalived -D -S 7
└─297368 /usr/sbin/keepalived -D -S 7

Mar 15 12:11:33 server2lb-fqdn Keepalived_vrrp[297368]: Sending gratuitous ARP on eth0 for 10.10.10.1
Mar 15 12:11:33 server2lb-fqdn Keepalived_vrrp[297368]: Sending gratuitous ARP on eth0 for 10.10.10.1
Mar 15 12:11:33 server2lb-fqdn Keepalived_vrrp[297368]: Remote SMTP server [127.0.0.1]:25 connected.
Mar 15 12:11:33 server2lb-fqdn Keepalived_vrrp[297368]: SMTP alert successfully sent.
Mar 15 12:11:38 server2lb-fqdn Keepalived_vrrp[297368]: (LB_VIP_QA) Sending/queueing gratuitous ARPs on eth0 for 10.10.10.1
Mar 15 12:11:38 server2lb-fqdn Keepalived_vrrp[297368]: Sending gratuitous ARP on eth0 for 10.10.10.1
Mar 15 12:11:38 server2lb-fqdn Keepalived_vrrp[297368]: Sending gratuitous ARP on eth0 for 10.10.10.1
Mar 15 12:11:38 server2lb-fqdn Keepalived_vrrp[297368]: Sending gratuitous ARP on eth0 for 10.10.10.1
Mar 15 12:11:38 server2lb-fqdn Keepalived_vrrp[297368]: Sending gratuitous ARP on eth0 for 10.10.10.1
Mar 15 12:11:38 server2lb-fqdn Keepalived_vrrp[297368]: Sending gratuitous ARP on eth0 for 10.10.10.1

[root@server2:~]# ip addr show|grep -i 10.10.10.1
inet 10.10.10.1/32 scope global eth0

As you see the VIP is now set on server2, just like expected – that's OK, everything works as expected. If the IP did not move double check the keepalived.conf on both nodes for errors or misconfigurations.

To recover the initial order of things so server1 is MASTER and server2 SLAVE host, we just have to switch on the keepalived on server1 machine.

[root@server1:~]# systemctl start keepalived

The automatic change of server1 to MASTER node and respective move of the VIP IP is done because of the higher priority (of importance we previously configured on server1 in keepalived.conf).

What we learned?

So what we learned in this article?
We have seen how to easily install and configure a High Availability Load balancer with Keepalived with single floating VIP IP address with 1 MASTER and 1 SLAVE host and a Haproxy example config with few frontends / App backends. We have seen how the config can be tested for potential errors and how we can monitor whether the VRRP2 network traffic flows between nodes and how to potentially debug it further if necessery.
Further on rawly explained some of the keepalived configurations but as keepalived can do pretty much more,for anyone seriously willing to deal with keepalived on a daily basis or just fine tune some already existing ones, you better read closely its manual page "man keepalived.conf" as well as the official Redhat Linux documentation page on setting up a Linux cluster with Keepalived (Be prepare for a small nightmare as the documentation of it seems to be a bit chaotic, and even I would say partly missing or opening questions on what does the developers did meant – not strange considering the havoc that is pretty much as everywhere these days.)

Finally once keepalived hosts are prepared, it was shown how to test the keepalived application cluster and Floating IP does move between nodes in case if one of the 2 keepalived nodes is inaccessible.

The same logic can be repeated multiple times and if necessery you can set multiple VIPs to expand the HA reachable IPs solution.

high-availability-with-two-vips-example-diagram

The presented idea is with haproxy forward Proxy server to proxy requests towards Application backend (servince machines), however if you need to set another set of server on the flow to process HTML / XHTML / PHP / Perl / Python programming code, with some common Webserver setup ( Nginx / Apache / Tomcat / JBOSS) and enable SSL Secure certificate with lets say Letsencrypt, this can be relatively easily done. If you want to implement letsencrypt and a webserver check this redundant SSL Load Balancing with haproxy & keepalived article.

That's all folks, hope you enjoyed.
If you need to configure keepalived Cluster or a consultancy write your query here 🙂

Tags: Ansible, application cluster, backup, Below, cluster config, common, configured, Configuring, CPU, Easy, everything, haproxy, howto, incoming traffic, inside, installation, keepalived, linux?, long time, Mar, master node, network, nightmare, Sending, server2, servers, Set, Slave, smtp, something, Stopping, test keepalived, var, vip address, virtual machines, Warning Journal
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Configure own Media streaming minidlna Linux server to access data from your Smart TV

Friday, February 18th, 2022

If you happen to buy or already own or just have to install a Smart TV to be connected with a LAN Network to a Linux based custom built NAS (Network Attached Storage) server. You might benefit of the smart TV to Share and Watching the Disk Storage Pictures, Music, Video files from the NAS to the Smart TV using the Media Server protocol.

You have certainly already faced the Media Server at your life on many locations in stores and Mall Buildings, because virtually any reoccuring advertisements, movies projected on the TVs, Kids entertainment or Floor and Buildings Room location schedules or timeline promition schedules are streamed using the Media Server protocol, for many years now. Thus having a brief idea about Media Server proto existence is foundamental stuff to be aware of for sysadmins and programmers.

Shortly about DLNA UPnP Media Streaming Protocol

Assuming that your Smart TV has been already connected to your Wireless Router 2.4Ghz or 5Ghz Wifi, one would think that the easiest way to share the files with the SmartTV is via something like a simple SAMBA Linux server via smb:// cifs:// protocols or via the good old NFS Server, however most of Samsung Smart TV and many other in year 2022 does not have embedded support for Samba SMB / CIFS Protocol but instead have support for the DLNA (Digital Living Network Alliance) streaming support. DLNA is part of the UPnP (Universal Plug and Play) Protocols, UPnP is also known to those using and familiar with Windows Operating Systems realm simply as UPnP AV Media server or Windows Media server.
Windows Media server for those who never heard it or used it allows you to build a Playlists with Media files Video and Audio data files, that can be then later played remotely via a Local LAN or even long distance over TCP / IP remote side connected Internet network.

1. Set up and Stream data via Media server on Windows PC / notebook with integrated Windows Media server

Windows Media server configuration on Windows 7, 10 and 11 is a relatively easy to configure via:

Network and Sharing Center -> Media Streaming Options -> Turn on Media Streaming

Then you have to define the name of the Media Library, configure whether Media server should show
on the Local Netework for other conected devices and Allow or Block access from the other network present devices.

2. Using a more advanced Media Server to get rid about the limitation of DLNA set of supported file codecs.

The Windows default embedded DLNA server is the easiest and fastest one to set up, but it’s not necessarily the best option.
Due to the way DLNA works, you can only stream certain types of media codecs supported by the server. If you have other types of media not defaultly supported and defined by DLNA win server, it just won’t work.

Thus thanksfully it was developed other DLNA servers improve this by offering real-time transcoding.
If you try to play an unsupported file, they’ll transcode it on-the-fly, streaming the video in a supported format to your DLNA device.
Just to name few of the DLNA Media Streaming servers that have supported for larger MPG Video, MP3 / MP4 and other Audio formats encodings,
you can try Plex or the Universal Media Server both of which are free to use under freeware license and have versions for Linux and Mac OS.

3. Setting up a free as in freedom DLNA server MiniDLNA (ReadyMedia) on GNU / Linux

ReadyMedia (formerly known as MiniDLNA) is a simple media server software, with the aim of being fully compliant with DLNA/UPnP-AV clients. It was originally developed by a NETGEAR employee for the ReadyNAS product line.

MiniDNLA daemon serves media files (music, pictures, and video) to clients on a network. Linux Media servers clients you can use to test or scan your network for existent Media servers are multiple perhaps the most famous ones are applications such as totem (for QT users) and Kodi (for KDE).
The devices that can be used with minidlna are devices such as portable media players (iPod), Smartphones, Televisions, Tablets, and gaming systems (such as PS3 and Xbox 360) etc.

ReadyMedia is a simple, lightweight, the downside of it is It does not have a web interface for administration and must be configured by editing a text file. But for a simple Video streaming in most cases does a great job.

3.1 Install the minidlna software package

Minidlna is available out of the box on most linux distributions (Fedora / CentOS / Debian / Ubuntu etc.) as of year 2022.

Install on Debian Linux (Deb based distro)

media-server:~# apt install minidlna –yes

Install on Fedora / CentOS (other RPM based distro)

media-server:~# yum install -y minidlna

3.2 Configure minidlna

– /etc/minidlna.conf – main config file
Open with text editor and set user= , media_dir= , port=, friendly_name= , network_interface= variables as minimum.
To be add minidlnad support symlinks to external file locations, set also wide_links=yes

media-server:~# vim /etc/minidlna.conf

#user=minidlna
user=root
media_dir=/var/www/owncloud/data
network_interface=eth0,eth1

# Port number for HTTP traffic (descriptions, SOAP, media transfer).
# This option is mandatory (or it must be specified on the command-line using
# "-p").
port=8200
# Name that the DLNA server presents to clients.
# Defaults to "hostname: username".
#friendly_name=
friendly_name=DLNAServer Linux
# set this to yes to allow symlinks that point outside user-defined media_dirs.
wide_links=yes
# Automatic discovery of new files in the media_dir directory.
#inotify=yes

Keep in mind that it is supported to provide separete media_dir and provide different USB / External Hard Drive or SD Card sources separated only by content be it Video, Audio or Pictures short named in config as (A,V,P).

media_dir=P,/media/usb/photos
media_dir=V,/media/external-disk/videos
media_dir=A,/media/sd-card/music

You might want to diasble / ineable the inotify depending on your liking, if you don't plan to place new files automated to the NAS and don't care to get indexed and streamed from the Media server you can disable it with inotify=no otherwise keep that on.

– /etc/default/minidlna – additional startup config to set minidlnad (daemon) options such as setup to run with admin superuser root:root
(usually it is safe to leave it empty and set the user=root, whether needed straight from /etc/minidlna.conf
That's all now go on and launch the minidlna and enable it to automatically boot on Linux boot.

media-server:~# systemctl start minidlna
media-server:~# systemctl enable minidlna
media-server:~# systemctl status minidlna

3.3 Rebuilt minidlna database with data indexed files

If you need to re- generate minidlna's database.
To do so stop the minidlna server with the

media-server:~# systemctop stop minidlna

command, then issue the following command (both commands should be run as root):

media-server:~# minidlna -R

Since this command might kept in the background and keep the minidlna server running with incorrect flags, after a minute or two kill minidlna process and relaunch the server via sysctl.

media-server:~# killall -9 minidlna
media-server:~# systemctl start minidlna

3.4 Permission Issues / Scanning issues

If you plan to place files in /home directory. You better have a seperate partition or folder *outside* your "home" directory devoted to your media. Default user with which minidlna runs is minidlna, this could prevent some files with root or other users being red. So either run minidlna daemon as root or as other user with whom all media files should be accessible.
If service runs as root:root, and still getting some scanning issues, check permissions on your files and remove special characters from file names.

media-server:~# tail -10 /var/log/minidlna/minidlna.log
[2022/02/17 22:51:36] scanner.c:489: warn: Unsuccessful getting details for /var/www/owncloud/data/Videos/Family-Videos/FILE006.MPG
[2022/02/17 22:52:08] scanner.c:819: warn: Scanning /var/www/owncloud/data finished (10637 files)!
[2022/02/17 22:52:08] playlist.c:135: warn: Parsing playlists…
[2022/02/17 22:52:08] playlist.c:269: warn: Finished parsing playlists.
minidlna.c:1126: warn: Starting MiniDLNA version 1.3.0.
minidlna.c:1186: warn: HTTP listening on port 8200
scanner.c:489: warn: Unsuccessful getting details for /var/www/owncloud/data/admin/files/origin/External SD card/media/Viber Images/IMG-4477de7b1eee273d5e6ae25236c5c223-V.jpg
scanner.c:489: warn: Unsuccessful getting details for /var/www/owncloud/data/Videos/Family-Video/FILE006.MPG
playlist.c:135: warn: Parsing playlists…
playlist.c:269: warn: Finished parsing playlists.

3.5. Fix minidlna Inotify errors

In /etc/sysctl.conf

Add:

fs.inotify.max_user_watches=65536

in a blank line at end of file and do

media-server:~# sysctl -p

Debugging minidlna problems, index errors, warnings etc

minidlna does write by default to /var/log/minidlna/minidlna.log inspect the log closely and you should get most of the time what is wrong with it.
Note that some files might not get indexed because minidlna won't support the strange file codecs such as SWF encoding, if you have some important files to stream that are not indexed by minidlna, then install and try one of the more sophisticated free software Media Servers for Linux:

MediaTomb
UniversalMediaServer
Plex

plex-media-streaming-server-screenshot

Note that most Linux users from my quick research shows, MediaTomb is the preferred advanced features Open Source Linux Media Server of choice for most of the guys.

mediatomb-linux-media-streaming-server-picture.jpg.webp

4. Test minidlna Linux servers works, getting information of other DLNA Servers on the network

media-server:~# lynx -dump http://127.0.0.1:8200
MiniDLNA status

Media library

Audio files 0
Video files 455
Image files 10182

Connected clients

ID Type IP Address HW Address Connections
0 Samsung Series [CDEFJ] 192.168.1.11 7C:0A:3D:88:A6:FA 0
1 Generic DLNA 1.5 192.168.0.241 00:16:4E:1D:48:05 0
2 Generic DLNA 1.5 192.168.1.18 00:16:3F:0D:45:05 0
3 Unknown 127.0.0.1 FF:FF:FF:FF:FF:FF 0

-1 connections currently open

Note that there is -1 connections (no active connections) currently to the server.
The 2 Generic DLNA 1.5 IPs are another DLNA servers provided by a OpenXEN hosted Windows 7 Virtual machines, that are also broadcasting their existence in the network. The Samsung Series [CDEFJ] is the DLNA client on the Samsung TV found, used to detect and stream data from the just configured Linux dlna server.

The DLNA Protocol enabled devices on a network as you can see are quite easy to access, querying localhost on the 8200 server dumps, what minidlna knows, the rest of IPs connecting should not be able to receive this info. But anyways since the minidlna does not have a special layers of security to access it, but the only way to restrict is filtering the 8200 port, it is a very good idea to put a good iptables firewall on the machine to allow only the devices that should have access to the data.

Further more if you happen to need to access the Media files on Linux from GUI you might use some client as upmentioned totem, VLC or if you need something more feature rich Java eezUPnP .

That's all folks !
Enjoy your media on the TV 🙂

Tags: access, configured, data, default user, Digital Living Network Alliance, DLNA, Enjoy, file, file names, Install, linux?, Media, Open Source Linux Media Server, org, owncloud, root root, setting, software package, stuff, support, wiki, www
Posted in Entertainment, Linux, Video Streaming | No Comments »

How to configure haproxy logging to separate file on Redhat Enterprise Linux 8.5 Ootpa

Thursday, February 3rd, 2022

haproxy-rsyslog-architecture-logging-picture

Configuring proper logging for haproxy is always a pain in the ass in Linux, because of rsyslogd various config syntax among versions, because of bugs in OS etc.
Today we have been given 2 Redhat 8.5 Linux servers where we had a task to start configuring haproxies, to have an idea on what is going on of course we had to enable proper haproxy logging in separate log file under separate local, for the test one can use haproxy's

log /dev/log local6

config, this is a general way to configure logging which I've described earlier in the article How to enable haproxy logging to a separate log /var/log/haproxy.log / prevent duplicate messages to appear in /var/log/messages
However this time I wanted to not use /dev/log as this device is also used by systemd / journald and theoretically could be used by other services and there might be multiple services logging to the same places possibly leading to some issue, thus I wanted to send and process the haproxy messages directly from rsyslog on RHEL 8.5.

Create a custom file that is loaded with the rest of configuration from /etc/rsyslog.conf with a line like:

# Include all config files in /etc/rsyslog.d/
include(file="/etc/rsyslog.d/*.conf" mode="optional")

Create 49_haproxy.conf with below content

[root@haproxy: ~]# vim /etc/rsyslog.d/49_haproxy.conf

$ModLoad imudp
$UDPServerAddress 127.0.0.1
$UDPServerRun 514
#2022/02/02: HAProxy logs to local6, save the messages
local6.* /var/log/haproxy.log
if ($programname == 'haproxy') then -/var/log/haproxy.log
& stop

touch /var/log/haproxy.log
chown haproxy:haproxy /var/log/haproxy.log

In /etc/haproxy/haproxy.cfg under global section to print in verbose mode messages (i.e. check, the haproxy is receiving properly sent traffic) do configure something like:

global
log 127.0.0.1 local6 debug

Eventually you might want to remove the debug word out of the config, if you don't want to log too much verbosily once everything is properly tested and configured

[root@haproxy: ~]# curl -v -c -k 10.10.192.135:16010
* Rebuilt URL to: 10.10.192.135:15010/
* Trying 10.10.192.135…
* TCP_NODELAY set
* Connected to 10.10.192.135 (10.10.192.135) port 15010 (#0)
> GET / HTTP/1.1
> Host: 10.10.192.135:15010
> User-Agent: curl/7.61.1
> Accept: */*
>
* Empty reply from server
* Connection #0 to host 10.10.192.135 left intact
curl: (52) Empty reply from server

In /var/log/haproxy.log you should get some messages like:

Feb 3 14:16:44 localhost.localdomain haproxy[25029]: proxy IN_Traffic_Bak has no server available!
Feb 3 14:16:44 localhost.localdomain haproxy[25029]: proxy IN_Traffic_Bak has no server available!
Feb 3 15:59:50 localhost.localdomain haproxy[25029]: [03/Feb/2022:15:59:50.162] 10.44.192.135:1348 -:- IN_Traffic/<NOSRV>:- -1/-1/0 0 SC 1/1/0/0/0 0/0
Feb 3 15:59:50 localhost.localdomain haproxy[25029]: [03/Feb/2022:15:59:50.162] 10.44.192.135:1348 -:- IN_Traffic/<NOSRV>:- -1/-1/0 0 SC 1/1/0/0/0 0/0
Feb 3 15:59:50 localhost.localdomain haproxy[25029]: [03/Feb/2022:15:59:50.162] 10.44.192.135:1348 -:- IN_Traffic/<NOSRV>:- -1/-1/0 0 SC 1/1/0/0/0 0/0

Tags: configured, haproxy, localdomain, localhost, log messages, logging, Redhat Enterprise Linux, rsyslog, server, various
Posted in Haproxy, Linux | No Comments »

Linux script to periodically log enabled systemctl services, configured network IPs and routings, server established connections and iptables firewall rules

Tuesday, January 25th, 2022

For those who are running some kind of server be it virtual or physical, where multiple people or many systemins have access, sometimes it could be quite a mess as someone due to miscommunication or whatever could change something on the configured Network Ethernet interfaces, or configured routing tables, or simply issue an update which might change the set of automatically set to run systemctl services due to update. Such changes on a Linux server Operating system often can remain unnoticed and could cause quite a harm. Even when the change is noticed the logical question occurs what was the previous network route on the server or what kind of network was configured on Ethernet interface ethX etc.
Problems like the described where, pretty common in many public Private Clouds or VMWare / XEN based Hypervisors that host multiple Virtual machines, for that reason I've developed a small script which is pretty dumb on the first glimpse but mostly useful as it keeps historical records of such important information.

#!/bin/sh
# script to show configured services on system, configured IPs, netstat state and network routes
# Script to be used during CentOS and Redhat Enterprise Linux RPM package updates with yum

output_file=network_ip_routes_services_status;
ddate=$(date '+%Y-%m-%d_%H-%M-%S');
iptables=$(which iptables);
if [ ! -d /root/logs/ ]; then
mkdir /root/logs/;
fi

echo "STARTED: $(date '+%Y-%m-%d_%H-%M-%S'):" | tee -a /root/logs/$output_file-$(hostname)-$ddate.log
echo -e "# systemctl list-unit-files\n" | tee -a /root/logs/$output_file-$(hostname)-$ddate.log
systemctl list-unit-files –type=service | grep enabled | tee -a /root/logs/$output_file-$(hostname)-$ddate.log
echo -e '# systemctl | grep ".service" | grep "running"\n' | tee -a /root/logs/$output_file-$(hostname)-$ddate.log
systemctl | grep ".service" | grep "running" | tee -a /root/logs/$output_file-$(hostname)-$ddate.log
echo -e "# netstat -tulpn\n" | tee -a /root/logs/$output_file-$(hostname)-$ddate.log
netstat -tulpn | tee -a /root/logs/$output_file-$(hostname)-$ddate.log
echo -e "# netstat -r\n" | tee -a /root/logs/$output_file-$(hostname)-$ddate.log
netstat -r | tee -a /root/logs/$output_file-$(hostname)-$ddate.log
echo -e "# ip a s\n" | tee -a /root/logs/$output_file-$(hostname)-$ddate.log
ip a s | tee -a /root/logs/$output_file-$(hostname)-$ddate.log
echo -e "# /sbin/route -n\n" | tee -a /root/logs/$output_file-$(hostname)-$ddate.log
/sbin/route -n | tee -a /root/logs/$output_file-$(hostname)-$ddate.log
echo -e "# $iptables -L -n\n" | tee -a /root/logs/$output_file-$(hostname)-$ddate.log
echo -e "# $iptables -t nat -L" | tee -a /root/logs/$output_file-$(hostname)-$ddate.log
$iptables -L -n | tee -a /root/logs/$output_file-$(hostname)-$ddate.log
$iptables -t nat -L | tee -a /root/logs/$output_file-$(hostname)-$ddate.log
echo "ENDED $(date '+%Y-%m-%d_%H-%M-%S'):" | tee -a /root/logs/$output_file-$(hostname)-$ddate.log

Script produces its logs inside /root/logs/network_ip_routes_services_status*hostname*currentdate*.log, put the script inside /root/ or wherever you like.

To keep an eye how network routing or ip configuration or firewall changed or there was a peak with the established connections towards daemons running on host (lets say requiring a machine upgrade), I've set the script to run as usually via cron job at the end of the predefined cron job tasks, like so:

# crontab -u root -e
# periodic dump and log network routing tables, netstat and systemctl list-unit-files
*/1 01 01,25 * * /root/show_running_services_netstat_ips_route1.sh 2>&1 >/dev/null

You can download a copy of show_running_services_netstat_ips_route1.sh script here.
The script is written without much of efficiency on mind, as you can see the with the multiple tee -a and for critical hosts it might be a good idea to rewrite it to use '>>' OPERAND instead, anyhows as most machines today are pretty powerful it doesn't really matter much.

Of course today such a script is quite archaic, as most big corporations are using much more complex monitoring software such as Zabbix, Prometheus or if some kind of Elastic Search is used Kibana etc. but for a basic needs and even for a double checking and comparing with other more advanced monitoring tools (in case if monitoring tools database gets damaged or temporary down until backupped), still I think such an oldschool simple monitoring script can be of use.

A good addition to that if you use a central logging server is to set another cron to periodically synchronize produced /root/logs/* to somewhere, here is how to do it with simple rsync (considering your host is configured to login with a user without password with ssh key authentication).

# HOSTNAME=$(hostname); rsync -axHv –ignore-existing -e 'ssh -p 22' /bashscripts/ -q -i –out-format="%t %f %b" –log-file=/var/log/rsync_sync_jobs.log –info=progress2 root@BACKUP_SERVER_HOST:/$(HOSTNAME)-logs/

Once something strange occurs with the machine, like the machine needs to be rebuild

I would be glad to hear if some of my readers uses some useful script which I can adopt myself. Cheers 🙂

Tags: configured, cron job, firewall rules, iptables firewall, logs, machines, Network Ethernet, running, script, systemctl
Posted in Linux, Linux Backup tools | No Comments »

Apache disable requests to not log to access.log Logfile through SetEnvIf and dontlog httpd variables

Monday, October 11th, 2021

Logging to Apache access.log is mostly useful as this is a great way to keep log on who visited your website and generate periodic statistics with tools such as Webalizer or Astats to keep track on your visitors and generate various statistics as well as see the number of new visitors as well most visited web pages (the pages which mostly are attracting your web visitors), once the log analysis tool generates its statistics, it can help you understand better which Web spiders visit your website the most (as spiders has a predefined) IP addresses, which can give you insight on various web spider site indexation statistics on Google, Yahoo, Bing etc. . Sometimes however either due to bugs in web spiders algorithms or inconsistencies in your website structure, some of the web pages gets double visited records inside the logs, this could happen for example if your website uses to include iframes.

Having web pages accessed once but logged to be accessed twice hence is erroneous and unwanted, and though that usually have to be fixed by the website programmers, if such approach is not easily doable in the moment and the website is running on critical production system, the double logging of request can be omitted thanks to a small Apache log hack with SetEnvIf Apache config directive. Even if there is no double logging inside Apache log happening it could be that some cron job or automated monitoring scripts or tool such as monit is making periodic requests to Apache and this is garbling your Log Statistics results.

In this short article hence I'll explain how to do remove certain strings to not get logged inside /var/log/httpd/access.log.

1. Check SetEnvIf is Loaded on the Webserver

On CentOS / RHEL Linux:

# /sbin/apachectl -M |grep -i setenvif
AH00558: httpd: Could not reliably determine the server's fully qualified domain name, using localhost.localdomain. Set the 'ServerName' directive globally to suppress this message
setenvif_module (shared)

On Debian / Ubuntu Linux:

# /usr/sbin/apache2ctl -M |grep -i setenvif
AH00548: NameVirtualHost has no effect and will be removed in the next release /etc/apache2/sites-enabled/000-default.conf:1
setenvif_module (shared)

2. Using SetEnvIf to omit certain string to get logged inside apache access.log

SetEnvIf could be used either in some certain domain VirtualHost configuration (if website is configured so), or it can be set as a global Apache rule from the /etc/httpd/conf/httpd.conf

To use SetEnvIf you have to place it inside a <Directory …></Directory> configuration block, if it has to be enabled only for a Certain Apache configured directory, otherwise you have to place it in the global apache config section.

To be able to use SetEnvIf, only in a certain directories and subdirectories via .htaccess, you will have defined in <Directory>

AllowOverride FileInfo

The general syntax to omit a certain Apache repeating string from keep logging with SetEnvIf is as follows:

SetEnvIf Request_URI "^/WebSiteStructureDirectory/ACCESS_LOG_STRING_TO_REMOVE$" dontlog

General syntax for SetEnvIf is as follows:

SetEnvIf attribute regex env-variable

SetEnvIf attribute regex [!]env-variable[=value] [[!]env-variable[=value]] …

Below is the overall possible attributes to pass as described in mod_setenvif official documentation.

Host

User-Agent

Referer

Accept-Language

Remote_Host: the hostname (if available) of the client making the request.

Remote_Addr: the IP address of the client making the request.

Server_Addr: the IP address of the server on which the request was received (only with versions later than 2.0.43).

Request_Method: the name of the method being used (GET, POST, etc.).

Request_Protocol: the name and version of the protocol with which the request was made (e.g., "HTTP/0.9", "HTTP/1.1", etc.).

Request_URI: the resource requested on the HTTP request line – generally the portion of the URL following the scheme and host portion without the query string.

Next locate inside the configuration the line:

CustomLog /var/log/apache2/access.log combined

To enable filtering of included strings, you'll have to append env=!dontlog to the end of line.

CustomLog /var/log/apache2/access.log combined env=!dontlog

You might be using something as cronolog for log rotation to prevent your WebServer logs to become too big in size and hard to manage, you can append env=!dontlog to it in same way.

If you haven't used cronolog is it is perhaps best to show you the package description.

server:~# apt-cache show cronolog|grep -i description -A10 -B5
Version: 1.6.2+rpk-2
Installed-Size: 63
Maintainer: Debian QA Group <packages@qa.debian.org>
Architecture: amd64
Depends: perl:any, libc6 (>= 2.4)
Description-en: Logfile rotator for web servers
A simple program that reads log messages from its input and writes
them to a set of output files, the names of which are constructed
using template and the current date and time. The template uses the
same format specifiers as the Unix date command (which are the same
as the standard C strftime library function).
.
It intended to be used in conjunction with a Web server, such as
Apache, to split the access log into daily or monthly logs:
.
TransferLog "|/usr/bin/cronolog /var/log/apache/%Y/access.%Y.%m.%d.log"
.
A cronosplit script is also included, to convert existing
traditionally-rotated logs into this rotation format.
Description-md5: 4d5734e5e38bc768dcbffccd2547922f
Homepage: http://www.cronolog.org/
Tag: admin::logging, devel::lang:perl, devel::library, implemented-in::c,
implemented-in::perl, interface::commandline, role::devel-lib,
role::program, scope::utility, suite::apache, use::organizing,
works-with::logfile
Section: web
Priority: optional
Filename: pool/main/c/cronolog/cronolog_1.6.2+rpk-2_amd64.deb
Size: 27912
MD5sum: 215a86766cc8d4434cd52432fd4f8fe7

If you're using cronolog to daily rotate the access.log and you need to filter out the strings out of the logs, you might use something like in httpd.conf:

CustomLog "|/usr/bin/cronolog –symlink=/var/log/httpd/access.log /var/log/httpd/access.log_%Y_%m_%d" combined env=!dontlog

3. Disable Apache logging access.log from certain USERAGENT browser

You can do much more with SetEnvIf for example you might want to omit logging requests from a UserAgent (browser) to end up in /dev/null (nowhere), e.g. prevent any Website requests originating from Internet Explorer (MSIE) to not be logged.

SetEnvIf User_Agent "(MSIE)" dontlog

CustomLog /var/log/apache2/access.log combined env=!dontlog

4. Disable Apache logging from requests coming from certain FQDN (Fully Qualified Domain Name) localhost 127.0.0.1 or concrete IP / IPv6 address

SetEnvIf Remote_Host "dns.server.com$" dontlog

CustomLog /var/log/apache2/access.log combined env=!dontlog

Of course for this to work, your website should have a functioning DNS servers and Apache should be configured to be able to resolve remote IPs to back resolve to their respective DNS defined Hostnames.

SetEnvIf recognized also perl PCRE Regular Expressions, if you want to filter out of Apache access log requests incoming from multiple subdomains starting with a certain domain hostname.

SetEnvIf Remote_Host "^example" dontlog

– To not log anything coming from localhost.localdomain address ( 127.0.0.1 ) as well as from some concrete IP address :

SetEnvIf Remote_Addr "127\.0\.0\.1" dontlog

SetEnvIf Remote_Addr "192\.168\.1\.180" dontlog

– To disable IPv6 requests that be coming at the log even though you don't happen to use IPv6 at all

SetEnvIf Request_Addr "::1" dontlog

CustomLog /var/log/apache2/access.log combined env=!dontlog

– Note here it is obligatory to escape the dots '.'

5. Disable robots.txt Web Crawlers requests from being logged in access.log

SetEnvIf Request_URI "^/robots\.txt$" dontlog

CustomLog /var/log/apache2/access.log combined env=!dontlog

Using SetEnvIfNoCase to read incoming useragent / Host / file requests case insensitve

The SetEnvIfNoCase is to be used if you want to threat incoming originators strings as case insensitive, this is useful to omit extraordinary regular expression SetEnvIf rules for lower upper case symbols.

SetEnvIFNoCase User-Agent "Slurp/cat" dontlog
SetEnvIFNoCase User-Agent "Ask Jeeves/Teoma" dontlog
SetEnvIFNoCase User-Agent "Googlebot" dontlog
SetEnvIFNoCase User-Agent "bingbot" dontlog
SetEnvIFNoCase Remote_Host "fastsearch.net$" dontlog

Omit from access.log logging some standard web files .css , .js .ico, .gif , .png and Referrals from own domain

Sometimes your own site scripts do refer to stuff on your own domain that just generates junks in the access.log to keep it off.

SetEnvIfNoCase Request_URI "\.(gif)|(jpg)|(png)|(css)|(js)|(ico)|(eot)$" dontlog

SetEnvIfNoCase Referer "www\.myowndomain\.com" dontlog

CustomLog /var/log/apache2/access.log combined env=!dontlog

6. Disable Apache requests in access.log and error.log completely

Sometimes at rare cases the produced Apache logs and error log is really big and you already have the requests logged in another F5 Load Balancer or Haproxy in front of Apache WebServer or alternatively the logging is not interesting at all as the Web Application served written in ( Perl / Python / Ruby ) does handle the logging itself.
I've earlier described how this is done in a good amount of details in previous article Disable Apache access.log and error.log logging on Debian Linux and FreeBSD

To disable it you will have to comment out CustomLog or set it to together with ErrorLog to /dev/null in apache2.conf / httpd.conf (depending on the distro)

CustomLog /dev/null
ErrorLog /dev/null

7. Restart Apache WebServer to load settings

An important to mention is in case you have Webserver with multiple complex configurations and there is a specific log patterns to omit from logs it might be a very good idea to:

a. Create /etc/httpd/conf/dontlog.conf / etc/apache2/dontlog.conf
add inside all your custom dontlog configurations
b. Include dontlog.conf from /etc/httpd/conf/httpd.conf / /etc/apache2/apache2.conf

Finally to make the changes take affect, of course you will need to restart Apache webserver depending on the distro and if it is with systemd or System V:

For systemd RPM based distro:

systemctl restart httpd

or for Deb based Debian etc.

systemctl apache2 restart

On old System V scripts systems:

On RedHat / CentOS etc. restart Apache with:

/etc/init.d/httpd restart

On Deb based SystemV:

/etc/init.d/apache2 restart

What we learned ?

We have learned about SetEnvIf how it can be used to prevent certain requests strings getting logged into access.log through dontlog, how to completely stop certain browser based on a useragent from logging to the access.log as well as how to omit from logging certain requests incoming from certain IP addresses / IPv6 or FQDNs and how to stop robots.txt from being logged to httpd log.

Finally we have learned how to completely disable Apache logging if logging is handled by other external application.

Tags: access, admin, amd64, apache2, Below, com, configured, CustomLog, General, httpd, inside, internet explorer, log, logging, MSIE, request, requests, UserAgent, variables, website programmers, www
Posted in Linux, Various, Web and CMS | No Comments »

Adding proxy to yum repository on Redhat / Fedora / CentOS and other RPM based Linux distributions, Listing and enabling new RPM repositories

Tuesday, September 7th, 2021

yum-add-proxy-host-for-redhat-linux-centos-list-rpm-repositories-enable-disable-repositories

Sometimes if you work in a company that is following PCI standards with very tight security you might need to use a custom company prepared RPM repositories that are accessible only via a specific custom maintained repositories or alternatively you might need the proxy node to access an external internet repository from the DMZ-ed firewalled zone where the servers lays .
Hence to still be able to maintain the RPM based servers up2date to the latest security patches and install software with yumone very useful feature of yum package manager is to use a proxy host through which you will reach your Redhat Package Manager files files.

1. The http_proxy and https_proxy shell variables

To set a proxy host you need to define there the IP / Hostname or the Fully Qualified Domain Name (FQDN).

By default "http_proxy and https_proxy are empty. As you can guess https_proxy is used if you have a Secure Socket Layer (SSL) certificate for encrypting the communication channel (e.g. you have https:// URL).

[root@rhel: ~]# echo $http_proxy
[root@rhel: ~]#

2. Setting passwordless or password protected proxy host via http_proxy, https_proxy variables

There is a one time very straight forward to configure proxying of traffic via a specific remote configured server with server bourne again shell (BASH)'s understood variables:

a.) Set password free open proxy to shell environment.

[root@centos: ~]# export https_proxy="https://remote-proxy-server:8080"

Now use yum as usual to update the available installabe package list or simply upgrade to the latest packages with lets say:

[root@rhel: ~]# yum check-update && yum update

b.) Configuring password protected proxy for yum

If your proxy is password protected for even tigher security you can provide the password on the command line as well.

[root@centos: ~]# export http_proxy="http://username:pAssW0rd@server:port/"

Note that if you have some special characters you will have to pass the string inside single quotes or escape them to make sure the password will properly handled to server, before trying out the proxy with yum, echo the variable.

[root@centos: ~]# export http_proxy='http://username:p@s#w:E@192.168.0.1:3128/'
[root@centos: ~]# echo $http_proxy
http://username:p@s#w:E@server:port/

Then do whatever with yum:

[root@centos: ~]# yum check-update && yum search sharutils

If something is wrong and proxy is not properly connected try to reach for the repository manually with curl or wget

[root@centos: ~]# curl -ilk http://download.fedoraproject.org/pub/epel/7/SRPMS/ /epel/7/SRPMS/
HTTP/1.1 302 Found
Date: Tue, 07 Sep 2021 16:49:59 GMT
Server: Apache
X-Frame-Options: SAMEORIGIN
X-Xss-Protection: 1; mode=block
X-Content-Type-Options: nosniff
Referrer-Policy: same-origin
Location: http://mirror.telepoint.bg/epel/7/SRPMS/
Content-Type: text/plain
Content-Length: 0
AppTime: D=2264
X-Fedora-ProxyServer: proxy01.iad2.fedoraproject.org
X-Fedora-RequestID: YTeYOE3mQPHH_rxD0sdlGAAAA80
X-Cache: MISS from pcfreak
X-Cache-Lookup: MISS from pcfreak:3128
Via: 1.1 pcfreak (squid/4.6)
Connection: keep-alive

Or if you need, you can test the user, password protected proxy with wget as so:

[root@centos: ~]# wget –proxy-user=USERNAME –proxy-password=PASSWORD http://your-proxy-domain.com/optional-rpms/

If you have lynx installed on the machine you can do the remote proxy successful authentication check with it with less typing:

[root@centos: ~]# lynx -pauth=USER:PASSWORD http://proxy-domain.com/optional-rpm/

3. Making yum proxy connection permanent via /etc/yum.conf

Perhaps the easiest and quickest way to add the http_proxy / https_proxy configured is to store it to automatically load on each server ssh login in your admin user (root) in /root/.bashrc or /root/.bash_profile or in the global /etc/profile or /etc/profile.d/custom.sh etc.

However if you don't want to have hacks and have more cleanness on the systems, the recommended "Redhat way" so to say is to store the configuration inside /etc/yum.conf

To do it via /etc/yum.conf you have to have some records there like:

# The proxy server – proxy server:port number
proxy=http://mycache.mydomain.com:3128
# The account details for yum connections
proxy_username=yum-user
proxy_password=qwerty-secret-pass

4. Listing RPM repositories and their state

As I had to install sharutils RPM package to the server which contains the file /bin/uuencode (that is provided on CentOS 7.9 Linux from Repo: base/7/x86_64 I had to check whether the repository was installed on the server.

To get a list of all yum repositories avaiable

[root@centos:/etc/yum.repos.d]# yum repolist all
Loaded plugins: fastestmirror
Loading mirror speeds from cached hostfile
* base: centos.telecoms.bg
* epel: mirrors.netix.net
* extras: centos.telecoms.bg
* remi: mirrors.netix.net
* remi-php74: mirrors.netix.net
* remi-safe: mirrors.netix.net
* updates: centos.telecoms.bg
repo id repo name status
base/7/x86_64 CentOS-7 – Base enabled: 10,072
base-debuginfo/x86_64 CentOS-7 – Debuginfo disabled
base-source/7 CentOS-7 – Base Sources disabled
c7-media CentOS-7 – Media disabled
centos-kernel/7/x86_64 CentOS LTS Kernels for x86_64 disabled
centos-kernel-experimental/7/x86_64 CentOS Experimental Kernels for x86_64 disabled
centosplus/7/x86_64 CentOS-7 – Plus disabled
centosplus-source/7 CentOS-7 – Plus Sources disabled
cr/7/x86_64 CentOS-7 – cr disabled
epel/x86_64 Extra Packages for Enterprise Linux 7 – x86_64 enabled: 13,667
epel-debuginfo/x86_64 Extra Packages for Enterprise Linux 7 – x86_64 – Debug disabled
epel-source/x86_64 Extra Packages for Enterprise Linux 7 – x86_64 – Source disabled
epel-testing/x86_64 Extra Packages for Enterprise Linux 7 – Testing – x86_64 disabled
epel-testing-debuginfo/x86_64 Extra Packages for Enterprise Linux 7 – Testing – x86_64 – Debug disabled
epel-testing-source/x86_64 Extra Packages for Enterprise Linux 7 – Testing – x86_64 – Source disabled
extras/7/x86_64 CentOS-7 – Extras enabled: 500
extras-source/7 CentOS-7 – Extras Sources disabled
fasttrack/7/x86_64 CentOS-7 – fasttrack disabled
remi Remi's RPM repository for Enterprise Linux 7 – x86_64 enabled: 7,229
remi-debuginfo/x86_64 Remi's RPM repository for Enterprise Linux 7 – x86_64 – debuginfo disabled
remi-glpi91 Remi's GLPI 9.1 RPM repository for Enterprise Linux 7 – x86_64 disabled
remi-glpi92 Remi's GLPI 9.2 RPM repository for Enterprise Linux 7 – x86_64 disabled
remi-glpi93 Remi's GLPI 9.3 RPM repository for Enterprise Linux 7 – x86_64 disabled
remi-glpi94 Remi's GLPI 9.4 RPM repository for Enterprise Linux 7 – x86_64 disabled
remi-modular Remi's Modular repository for Enterprise Linux 7 – x86_64 disabled
remi-modular-test Remi's Modular testing repository for Enterprise Linux 7 – x86_64 disabled
remi-php54 Remi's PHP 5.4 RPM repository for Enterprise Linux 7 – x86_64 disabled
remi-php55 Remi's PHP 5.5 RPM repository for Enterprise Linux 7 – x86_64 disabled
remi-php55-debuginfo/x86_64 Remi's PHP 5.5 RPM repository for Enterprise Linux 7 – x86_64 – debuginfo disabled
!remi-php56 Remi's PHP 5.6 RPM repository for Enterprise Linux 7 – x86_64 disabled
remi-php56-debuginfo/x86_64 Remi's PHP 5.6 RPM repository for Enterprise Linux 7 – x86_64 – debuginfo disabled
remi-php70 Remi's PHP 7.0 RPM repository for Enterprise Linux 7 – x86_64 disabled
remi-php70-debuginfo/x86_64 Remi's PHP 7.0 RPM repository for Enterprise Linux 7 – x86_64 – debuginfo disabled
remi-php70-test Remi's PHP 7.0 test RPM repository for Enterprise Linux 7 – x86_64 disabled
remi-php70-test-debuginfo/x86_64 Remi's PHP 7.0 test RPM repository for Enterprise Linux 7 – x86_64 – debuginfo disabled
remi-php71 Remi's PHP 7.1 RPM repository for Enterprise Linux 7 – x86_64 disabled
remi-php71-debuginfo/x86_64 Remi's PHP 7.1 RPM repository for Enterprise Linux 7 – x86_64 – debuginfo disabled
remi-php71-test Remi's PHP 7.1 test RPM repository for Enterprise Linux 7 – x86_64 disabled
remi-php71-test-debuginfo/x86_64 Remi's PHP 7.1 test RPM repository for Enterprise Linux 7 – x86_64 – debuginfo disabled
!remi-php72 Remi's PHP 7.2 RPM repository for Enterprise Linux 7 – x86_64 disabled
remi-php72-debuginfo/x86_64 Remi's PHP 7.2 RPM repository for Enterprise Linux 7 – x86_64 – debuginfo disabled
remi-php72-test Remi's PHP 7.2 test RPM repository for Enterprise Linux 7 – x86_64 disabled
remi-php72-test-debuginfo/x86_64 Remi's PHP 7.2 test RPM repository for Enterprise Linux 7 – x86_64 – debuginfo disabled
remi-php73 Remi's PHP 7.3 RPM repository for Enterprise Linux 7 – x86_64 disabled
remi-php73-debuginfo/x86_64 Remi's PHP 7.3 RPM repository for Enterprise Linux 7 – x86_64 – debuginfo disabled
remi-php73-test Remi's PHP 7.3 test RPM repository for Enterprise Linux 7 – x86_64 disabled
remi-php73-test-debuginfo/x86_64 Remi's PHP 7.3 test RPM repository for Enterprise Linux 7 – x86_64 – debuginfo disabled
remi-php74 Remi's PHP 7.4 RPM repository for Enterprise Linux 7 – x86_64 enabled: 423
remi-php74-debuginfo/x86_64 Remi's PHP 7.4 RPM repository for Enterprise Linux 7 – x86_64 – debuginfo disabled
remi-php74-test Remi's PHP 7.4 test RPM repository for Enterprise Linux 7 – x86_64 disabled
remi-php74-test-debuginfo/x86_64 Remi's PHP 7.4 test RPM repository for Enterprise Linux 7 – x86_64 – debuginfo disabled
remi-php80 Remi's PHP 8.0 RPM repository for Enterprise Linux 7 – x86_64 disabled
remi-php80-debuginfo/x86_64 Remi's PHP 8.0 RPM repository for Enterprise Linux 7 – x86_64 – debuginfo disabled
remi-php80-test Remi's PHP 8.0 test RPM repository for Enterprise Linux 7 – x86_64 disabled
remi-php80-test-debuginfo/x86_64 Remi's PHP 8.0 test RPM repository for Enterprise Linux 7 – x86_64 – debuginfo disabled
remi-safe Safe Remi's RPM repository for Enterprise Linux 7 – x86_64 enabled: 4,549
remi-safe-debuginfo/x86_64 Remi's RPM repository for Enterprise Linux 7 – x86_64 – debuginfo disabled
remi-test Remi's test RPM repository for Enterprise Linux 7 – x86_64 disabled
remi-test-debuginfo/x86_64 Remi's test RPM repository for Enterprise Linux 7 – x86_64 – debuginfo disabled
updates/7/x86_64 CentOS-7 – Updates enabled: 2,741
updates-source/7 CentOS-7 – Updates Sources disabled
zabbix/x86_64 Zabbix Official Repository – x86_64 enabled: 178
zabbix-debuginfo/x86_64 Zabbix Official Repository debuginfo – x86_64 disabled
zabbix-frontend/x86_64 Zabbix Official Repository frontend – x86_64 disabled
zabbix-non-supported/x86_64 Zabbix Official Repository non-supported – x86_64 enabled: 5
repolist: 39,364

[root@centos:/etc/yum.repos.d]# yum repolist all|grep -i 'base/7/x86_64'
base/7/x86_64 CentOS-7 – Base enabled: 10,072

As you can see in CentOS 7 sharutils is enabled from default repositories, however this is not the case on Redhat 7.9, hence to install sharutils there you can one time enable RPM repository to install sharutils

[root@centos:/etc/yum.repos.d]# yum –enablerepo=rhel-7-server-optional-rpms install sharutils

To install zabbix-agent on the same Redhat server, without caring that I need precisely know the RPM repository that is providing zabbix agent that in that was (Repo: 3party/7Server/x86_64) I had to:

[root@centos:/etc/yum.repos.d]# yum –enablerepo \* install zabbix-agent zabbix-sender

Permanently enabling repositories of course is possible via editting or creating fresh new file configuration manually on CentOS / Fedora under directory /etc/yum.repos.d/.
On Redhat Enterprise Linux servers it is easier to use the subscription-manager command instead, like this:

[root@rhel:/root]# subscription-manager repos –disable=epel/7Server/x86_64

[root@rhel:/root]# subscription-manager repos –enable=rhel-6-server-optional-rpms

Tags: admin user, configured, enable, Enterprise Linux, external internet, linux?, Listing, MISS, passwordless, proxy, repository, rpm, SAMEORIGIN, servers, SRPMS, variables, yum
Posted in Linux, Linux Package Management | No Comments »

OpenVZ enable or disable auto start on Linux Hypervisor host boot for Virtual Machine containers

Wednesday, July 7th, 2021

To make OpenVZ / Virtuozzo Hypervisor servers and you are not sure whether your configured container virtual machines are configured to automatically boot on Linux Physical OS host boot in case of restart after patch update set or after unexpected shutdown due to Kernel / OS bug a hang or due to some electricity Power outage.

To check what is your current configuration for Virtual Environment on CentOS Linux you need to check inside /etc/sysconfig/vz-scripts/VEID.conf
You need to check the value for inside the file

ONBOOT=""

To get the exact ID of "VEID.conf of the current openvz guest VM containers exec:

[root@openvz vz-scripts]# vzlist -a
CTID NPROC STATUS IP_ADDR HOSTNAME
300 23 running 10.10.10.1 VirtualMachine1
301 25 running 10.10.10.2 VirtualMachine2

[root@openvz ~]# cd /etc/sysconfig/vz-scripts
[root@gbapp2 vz-scripts]# pwd
/etc/sysconfig/vz-scripts

[root@openvz vz-scripts]# grep -i ONBOOT 300.conf 301.conf
300.conf:ONBOOT="yes"
301.conf:ONBOOT="yes"

If you happen to have configured ONBOOT="no" you will need to the change to respective VEID.conf:

vi /etc/sysconfig/vz-scripts/VEID.conf

search for

ONBOOT=”no”

and change to

ONBOOT=”yes”

OpenVZ_virtuozzo-standard-process-tree-landscape

OpenVZ server process tree. The colors of the virtual severs are indicated by colors.

OpenVZ Quick cheat sheet commands

This change will auto-start the VPS container next time the host Hypervisor node is rebooted.
If you happen to have daily work with OpenVZ legacy systems like I do you might find also useful the following OpenVZ Cheatsheet pdf document.

A miniature quick cheatsheet for OpenVZ Virtualion, in case if you are like me and you have to use various virtualization technologies and tend to forget is as below:

vzlist # List running instances
vzlist -a # List all instances

vzctl stop <instance>
vzctl start <instance>
vzctl status <instance>

vzctl exec <instance> <command> # Run a command

vzctl enter <instance> # Get console

vzyum <instance> install <package> # Install a package

# Change properties
vzctl set <instance> –hostname <hostname> –save
vzctl set <instance> –ipadd <IP> –save
vzctl set <instance> –userpasswd root:<password> –save

If need to get more insight on how OpenVZ Virtualization does work on a low level and stretch out its possibilities, an old but useful document you might want to check is OpenVZ-Users-Guide PDF.

If you need it to hava e copy of it openvz_cheat_sheet.txt.

Tags: auto start, check, configured, disable, Linux Hypervisor, need, ONBOOT, root password, sysconfig, virtual machines
Posted in Linux, System Administration, Virtual Machines | No Comments »

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Posts Tagged ‘configured’

How to start Syslog ( Syslog-ng ) on IBM AIX

1. Install / Uninstall syslog-ng on AIX

1.1. Install syslog-ng on AIX

1.2. Uninstall syslog-ng on AIX

2. Set Automatic start of syslog-ng on AIX

3. Check syslog-ng configuration is correct

How to monitor Haproxy Application server backends with Zabbix userparameter autodiscovery scripts

1. Create the required haproxy_discovery.sh and haproxy_stats.sh scripts

2. Create the userparameter_haproxy_backend.conf

3. Create new simple template for the Application backend Monitoring and link it to monitored host

4. Restart Zabbix-agent, in while check autodiscovery data is in Zabbix Server

Create Linux High Availability Load Balancer Cluster with Keepalived and Haproxy on Linux

1. Install keepalived and haproxy on machines

2. Configure haproxy (haproxy.cfg) on both server1 and server2

…

3. Configure keepalived on both servers

4. Test Keepalived keepalived.conf configuration syntax is OK

5. Prepare rsyslog configuration and Inlcude additional keepalived options
to force keepalived log into /var/log/keepalived.log

6. Monitoring VRRP traffic of the two keepaliveds with tcpdump

7. Testing keepalived on server1 and server2 maachines VIP floating IP really works

What we learned?

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Posts Tagged ‘configured’

1. Install / Uninstall syslog-ng on AIX

1.1. Install syslog-ng on AIX

1.2. Uninstall syslog-ng on AIX

2. Set Automatic start of syslog-ng on AIX

3. Check syslog-ng configuration is correct

1. Create the required haproxy_discovery.sh and haproxy_stats.sh scripts

2. Create the userparameter_haproxy_backend.conf

3. Create new simple template for the Application backend Monitoring and link it to monitored host

4. Restart Zabbix-agent, in while check autodiscovery data is in Zabbix Server

How to pass Real (Internet) Source IPs from Haproxy "mode tcp" to Local LAN Webservers ?

2. Enable remoteip proxy protocol on Webservers

3. Modify remoteip.conf file and allow IPs of haproxies or F5s

4. Enable RemoteIP Proxy Protocol in apache2.conf / httpd.conf or Virtualhost custom config

5. Change default configured Apache LogFormat

6. Check proxy protocol is properly enabled on Apaches

7. Check apache log if remote Real Internet Source IPs are properly logged

Sum it up, What was done?

1. Install keepalived and haproxy on machines

2. Configure haproxy (haproxy.cfg) on both server1 and server2

…

3. Configure keepalived on both servers

4. Test Keepalived keepalived.conf configuration syntax is OK

5. Prepare rsyslog configuration and Inlcude additional keepalived options to force keepalived log into /var/log/keepalived.log

6. Monitoring VRRP traffic of the two keepaliveds with tcpdump

7. Testing keepalived on server1 and server2 maachines VIP floating IP really works

What we learned?

Shortly about DLNA UPnP Media Streaming Protocol

1. Set up and Stream data via Media server on Windows PC / notebook with integrated Windows Media server

2. Using a more advanced Media Server to get rid about the limitation of DLNA set of supported file codecs.

3. Setting up a free as in freedom DLNA server MiniDLNA (ReadyMedia) on GNU / Linux

3.1 Install the minidlna software package

3.2 Configure minidlna

3.3 Rebuilt minidlna database with data indexed files

3.4 Permission Issues / Scanning issues

3.5. Fix minidlna Inotify errors

4. Test minidlna Linux servers works, getting information of other DLNA Servers on the network

1. Check SetEnvIf is Loaded on the Webserver

2. Using SetEnvIf to omit certain string to get logged inside apache access.log

3. Disable Apache logging access.log from certain USERAGENT browser

4. Disable Apache logging from requests coming from certain FQDN (Fully Qualified Domain Name) localhost 127.0.0.1 or concrete IP / IPv6 address

5. Disable robots.txt Web Crawlers requests from being logged in access.log

6. Disable Apache requests in access.log and error.log completely

7. Restart Apache WebServer to load settings

What we learned ?

1. The http_proxy and https_proxy shell variables

2. Setting passwordless or password protected proxy host via http_proxy, https_proxy variables

3. Making yum proxy connection permanent via /etc/yum.conf

4. Listing RPM repositories and their state

OpenVZ Quick cheat sheet commands

Daily Bible quote

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Useful blog? Help it:

Links to Other Places

Recent Posts

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Tags

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5. Prepare rsyslog configuration and Inlcude additional keepalived options
to force keepalived log into /var/log/keepalived.log