Fix Blocked Unresponsive keyboard keys on Windows 7 / 10


February 25th, 2020

Scroll-lock-keboard-work-around-windows-issues

 

The Problem


If you're still using Windows 7 Operating system in your company due to some weird security concern policies and your company gets custom end user updates from Microsoft due to a special EULA agreement and you are new to using Windows E.g. have for many users used for your daily work Linux and Mac OS you might hit a strange issue wtih many of the keyboard keys strangely being locked with some of the keys such as Num Lock, Escape tab working where the Alphabet keys then don't panic. This is not a Windows bug its a feature (as usual) 🙂
 

Reason behind Blocked Unresponsive Keyboard

 

First logical thought I had is maybe my Logitech K120 Membrane 17 EURO cheap keyboard externally attached keyboard broke up thus I've tried to connect another LOGIC keyboard I had at hand just to assure myself the problem with partial keys on kbd reacting was present with the other Working keyboard as well.
This was an indicator that either the custom installed Windows by the company Helpdesk Office with the preassumed common additional features for corporations such as Keyloggers on this Laptop has messed up somohow the Windows service that is managing the keyboard or some kind of mechanical error or electronic circuit on the laptop embedded keyboard has occured or the KBD DLL Loaded driver damaged
I have to say here a colleague of mine was having a weird keyboard problems back in the day when I was still working in Project Services as a Web and Middleware in Hewlett Packard, where misteriously a character was added to his typed content just like a key on his keyboard has stuck and he experienced this issue for quite some time, he opened the keyboard to physically check whether all is okay and even checked the keyboard electricity whether levels on each of the keys and he couldn't find anything, and after running Malware Bytes anti-malware and a couple of other anti-malware programs which found his computer was infected with Malware and issue resolved.

 

Hard Fix – Reboot ..

 

As as a solution most times so far I've restarted the Windows which was reloading the Windows kernel / DLL libraries etc.

However just hit to this Windows accessibility feature once again today and since this is not the first time I end up with unworking keyboard (perhaps due to my often) furious fast typing – where I press sometimes multiple keys in parallel as a typing error then you trigger the Windows Disabled accessibiltiy Windows Feature, which as I thought makes the PC only usable for Mouse but unusuable for providing any meaningful keyboard input.

This problem I've faced already multiple times and usually the work around was the good known Windows User recipee phrase "Restart and It will get fixed", this time I was pissed off and didn't wanted to loose another 5 minutes in Restarting Reconnecting to the Company's Cisco Secure VPN reopening all my used files Notepad++ / Outlook / Browsers etc plus I was already part of online Lync (Skype) Meeting in which Colleague was Sharing his remote Desktop checking some important stuff about Zabbix Monitored AIX machine, hence didn't wanted to restart but still wanted to use my computer and type some stuff to send Email and do a simple googling.

Temporary work around to complete work with Virtual Keyboard

Hence as a temporary work around, I've used the Windows Virtual Keyboard, I've mentioned it in the earlier  blog post – How to run Virtual Keyboard in Windows XP / Vista article
To do so I'verun by typing osk command in cmd.exe command Prompt:

Either Search for osk.exe from Start menu

windows-7-osk-virtual-keyboard-screenshot-from-start-menu

or run via command line via

Windows Button (on the Keyboard) + R and run
 

cmd.exe -> osk

 


windows-7-osk-virtual-keyboard-screenshot2

 

Solution Without PC Restart


After a bit of thought and Googling I've found the fix  here

From the Start -> Control Panel from here I had to go to Accessibility Options.
Select Ease of Access Center.

Keyboard_Locked-Windows_7_Accessibility_Options-HP-Customer-Support

Select the keyboard settings and
Ensure the following options are unchecked: Turn on Sticky Keys, Turn on Toggle Keys and Turn on Filter Keys.

Keyboard-Locked_Find-Out-How-to-Unlock-make-keyboard-easier-to-use

I've found in the Turn on Toggle Keys tick present (e.g. service was enabled) – hence  after unticking it and 

Press Apply and OK, keyboard restored its usual functions.
Now all left was to  Enjoy as your keyboard was back usable and I could conitnue my Citrix sessions and SSH console Superputty terminals  and complete my started to write E-mail
without loosing time meanlessly for reboot.

 

Windows 10 Disable the Filter Keys option

 

This feature makes your keyboard ignore brief or repeated keystrokes, which might have led to your WinKey issue in Windows 10. To disable filter keys, use the instructions below:

1. Right-click on your Start menu icon.
2. Select Settings from the menu.
3. Navigate to Ease of Access and click on it.
4. Go to the left pane and click Keyboard.
5. Locate the Filter Keys feature.
6. Toggle it off.
7. Check if this manoeuvre has resolved your issue.
 

Closing Notes 


Of course this might be not always the fix, as sometimes it could be that the Winblows just blows your keyboard buffer due to some buggy application or a bug, but in most of the times that should solve it 🙂
If it didn't go through and debug all the other possible reasons, check whether you have a faulty keyboard cable (if you're still on a non-bluetooth Wired Keyboard), unplug and plug the keyboard again,
scan the computer for spyware and malware, rethink what really happened or what have you done until the problem occured and whether blocked keyboard is triggered by your user action or was triggered
by some third party software anti-virus stuff that did it as an attempt to prevent keylog sniffer / Virus or other weird stuff.

How to check if shared library is loaded in AIX OS – Fix missing libreadline.so.7


February 20th, 2020

ibm-aix-logo1

I've had to find out whether an externally Linux library is installed  on AIX system and whether something is not using it.
The returned errors was like so:

 

# gpg –export -a

Could not load program gpg:
Dependent module /opt/custom/lib/libreadline.a(libreadline.so.7) could not be loaded.
Member libreadline.so.7 is not found in archive


After a bit of investigation, I found that gpg was failing cause it linked to older version of libreadline.so.6, the workaround was to just substitute the newer version of libreadline.so.7 over the original installed one.

Thus I had a plan to first find out whether this libreadline.a is loaded and recognized by AIX UNIX first and second find out whether some of the running processes is not using that library.
I've come across this interesting IBM official documenation that describes pretty good insights on how to determine whether a shared library  is currently loaded on the system. which mentions the genkld command that is doing
exactly what I needed.

In short:
genkld – creates a list that is printed to the console that shows all loaded shared libraries

genkld-screenshot-aix-unix

Next I used lsof (list open files) command to check whether there is in real time opened libraries by any of the running programs on the system.

After not finding anything and was sure the library is neither loaded as a system library in AIX nor it is used by any of the currently running AIX processes, I was sure I could proceed to safely overwrite libreadline.a (libreadline.so.6) with libreadline.a with (libreadline.so.7).

The result of that is again a normally running gpg as ldd command shows the binary is again normally linked to its dependend system libraries.
 

aix# ldd /usr/bin/gpg
/usr/bin/gpg needs:
         /usr/lib/threads/libc.a(shr.o)
         /usr/lib/libpthreads.a(shr_comm.o)
         /usr/lib/libpthreads.a(shr_xpg5.o)
         /opt/freeware/lib/libintl.a(libintl.so.1)
         /opt/freeware/lib/libreadline.a(libreadline.so.7)
         /opt/freeware/lib/libiconv.a(libiconv.so.2)
         /opt/freeware/lib/libz.a(libz.so.1)
         /opt/freeware/lib/libbz2.a(libbz2.so.1)
         /unix
         /usr/lib/libcrypt.a(shr.o)
         /opt/freeware/lib/libiconv.a(shr4.o)
         /usr/lib/libcurses.a(shr42.o)

 

 

# gpg –version
gpg (GnuPG) 1.4.22
Copyright (C) 2015 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.

 

Home: ~/.gnupg
Supported algorithms:
Pubkey: RSA, RSA-E, RSA-S, ELG-E, DSA
Cipher: IDEA, 3DES, CAST5, BLOWFISH, AES, AES192, AES256, TWOFISH,
        CAMELLIA128, CAMELLIA192, CAMELLIA256
Hash: MD5, SHA1, RIPEMD160, SHA256, SHA384, SHA512, SHA224
Compression: Uncompressed, ZIP, ZLIB, BZIP2

 

 

How to enable HaProxy logging to a separate log /var/log/haproxy.log / prevent HAProxy duplicate messages to appear in /var/log/messages


February 19th, 2020

haproxy-logging-basics-how-to-log-to-separate-file-prevent-duplicate-messages-haproxy-haproxy-weblogo-squares
haproxy  logging can be managed in different form the most straight forward way is to directly use /dev/log either you can configure it to use some log management service as syslog or rsyslogd for that.

If you don't use rsyslog yet to install it: 

# apt install -y rsyslog

Then to activate logging via rsyslogd we can should add either to /etc/rsyslogd.conf or create a separte file and include it via /etc/rsyslogd.conf with following content:
 

Enable haproxy logging from rsyslogd


Log haproxy messages to separate log file you can use some of the usual syslog local0 to local7 locally used descriptors inside the conf (be aware that if you try to use some wrong value like local8, local9 as a logging facility you will get with empty haproxy.log, even though the permissions of /var/log/haproxy.log are readable and owned by haproxy user.

When logging to a local Syslog service, writing to a UNIX socket can be faster than targeting the TCP loopback address. Generally, on Linux systems, a UNIX socket listening for Syslog messages is available at /dev/log because this is where the syslog() function of the GNU C library is sending messages by default. To address UNIX socket in haproxy.cfg use:

log /dev/log local2 


If you want to log into separate log each of multiple running haproxy instances with different haproxy*.cfg add to /etc/rsyslog.conf lines like:

local2.* -/var/log/haproxylog2.log
local3.* -/var/log/haproxylog3.log


One important note to make here is since rsyslogd is used for haproxy logging you need to have enabled in rsyslogd imudp and have a UDP port listener on the machine.

E.g. somewhere in rsyslog.conf or via rsyslog include file from /etc/rsyslog.d/*.conf needs to have defined following lines:

$ModLoad imudp
$UDPServerRun 514


I prefer to use external /etc/rsyslog.d/20-haproxy.conf include file that is loaded and enabled rsyslogd via /etc/rsyslog.conf:

# vim /etc/rsyslog.d/20-haproxy.conf

$ModLoad imudp
$UDPServerRun 514​
local2.* -/var/log/haproxy2.log


It is also possible to produce different haproxy log output based on the severiy to differentiate between important and less important messages, to do so you'll need to rsyslog.conf something like:
 

# Creating separate log files based on the severity
local0.* /var/log/haproxy-traffic.log
local0.notice /var/log/haproxy-admin.log

 

Prevent Haproxy duplicate messages to appear in /var/log/messages

If you use local2 and some default rsyslog configuration then you will end up with the messages coming from haproxy towards local2 facility producing doubled simultaneous records to both your pre-defined /var/log/haproxy.log and /var/log/messages on Proxy servers that receive few thousands of simultanous connections per second.
This is a problem since doubling the log will produce too much data and on systems with smaller /var/ partition you will quickly run out of space + this haproxy requests logging to /var/log/messages makes the file quite unreadable for normal system events which are so important to track clearly what is happening on the server daily.

To prevent the haproxy duplicate messages you need to define somewhere in rsyslogd usually /etc/rsyslog.conf local2.none near line of facilities configured to log to file:

*.info;mail.none;authpriv.none;cron.none;local2.none     /var/log/messages

This configuration should work but is more rarely used as most people prefer to have haproxy log being written not directly to /dev/log which is used by other services such as syslogd / rsyslogd.

To use /dev/log to output logs from haproxy configuration in global section use config like:
 

global
        log /dev/log local2 debug
        chroot /var/lib/haproxy
        stats socket /run/haproxy/admin.sock mode 660 level admin
        stats timeout 30s
        user haproxy
        group haproxy
        daemon

The log global directive basically says, use the log line that was set in the global section for whole config till end of file. Putting a log global directive into the defaults section is equivalent to putting it into all of the subsequent proxy sections.

Using global logging rules is the most common HAProxy setup, but you can put them directly into a frontend section instead. It can be useful to have a different logging configuration as a one-off. For example, you might want to point to a different target Syslog server, use a different logging facility, or capture different severity levels depending on the use case of the backend application. 

Insetad of using /dev/log interface that is on many distributions heavily used by systemd to store / manage and distribute logs,  many haproxy server sysadmins nowdays prefer to use rsyslogd as a default logging facility that will manage haproxy logs.
Admins prefer to use some kind of mediator service to manage log writting such as rsyslogd or syslog, the reason behind might vary but perhaps most important reason is  by using rsyslogd it is possible to write logs simultaneously locally on disk and also forward logs  to a remote Logging server  running rsyslogd service.

Logging is defined in /etc/haproxy/haproxy.cfg or the respective configuration through global section but could be also configured to do a separate logging based on each of the defined Frontend Backends or default section. 
A sample exceprt from this section looks something like:

#———————————————————————
# Global settings
#———————————————————————
global
    log         127.0.0.1 local2

    chroot      /var/lib/haproxy
    pidfile     /var/run/haproxy.pid
    maxconn     4000
    user        haproxy
    group       haproxy
    daemon

    # turn on stats unix socket
    stats socket /var/lib/haproxy/stats

#———————————————————————
defaults
    mode                    tcp
    log                     global
    option                  tcplog
    #option                  dontlognull
    #option http-server-close
    #option forwardfor       except 127.0.0.0/8
    option                  redispatch
    retries                 7
    #timeout http-request    10s
    timeout queue           10m
    timeout connect         30s
    timeout client          20m
    timeout server          10m
    #timeout http-keep-alive 10s
    timeout check           30s
    maxconn                 3000

 

 

# HAProxy Monitoring Config
#———————————————————————
listen stats 192.168.0.5:8080                #Haproxy Monitoring run on port 8080
    mode http
    option httplog
    option http-server-close
    stats enable
    stats show-legends
    stats refresh 5s
    stats uri /stats                            #URL for HAProxy monitoring
    stats realm Haproxy\ Statistics
    stats auth hproxyauser:Password___          #User and Password for login to the monitoring dashboard

 

#———————————————————————
# frontend which proxys to the backends
#———————————————————————
frontend ft_DKV_PROD_WLPFO
    mode tcp
    bind 192.168.233.5:30000-31050
    option tcplog
    log-format %ci:%cp\ [%t]\ %ft\ %b/%s\ %Tw/%Tc/%Tt\ %B\ %ts\ %ac/%fc/%bc/%sc/%rc\ %sq/%bq
    default_backend Default_Bakend_Name


#———————————————————————
# round robin balancing between the various backends
#———————————————————————
backend bk_DKV_PROD_WLPFO
    mode tcp
    # (0) Load Balancing Method.
    balance source
    # (4) Peer Sync: a sticky session is a session maintained by persistence
    stick-table type ip size 1m peers hapeers expire 60m
    stick on src
    # (5) Server List
    # (5.1) Backend
    server Backend_Server1 10.10.10.1 check port 18088
    server Backend_Server2 10.10.10.2 check port 18088 backup


The log directive in above config instructs HAProxy to send logs to the Syslog server listening at 127.0.0.1:514. Messages are sent with facility local2, which is one of the standard, user-defined Syslog facilities. It’s also the facility that our rsyslog configuration is expecting. You can add more than one log statement to send output to multiple Syslog servers.

Once rsyslog and haproxy logging is configured as a minumum you need to restart rsyslog (assuming that haproxy config is already properly loaded):

# systemctl restart rsyslogd.service

To make sure rsyslog reloaded successfully:

systemctl status rsyslogd.service


Restarting HAproxy

If the rsyslogd logging to 127.0.0.1 port 514 was recently added a HAProxy restart should also be run, you can do it with:
 

# /usr/sbin/haproxy -f /etc/haproxy/haproxy.cfg -D -p /var/run/haproxy.pid -sf $(cat /var/run/haproxy.pid)


Or to restart use systemctl script (if haproxy is not used in a cluster with corosync / heartbeat).

# systemctl restart haproxy.service

You can control how much information is logged by adding a Syslog level by

    log         127.0.0.1 local2 info


The accepted values are the standard syslog security level severity:

Value Severity Keyword Deprecated keywords Description Condition
0 Emergency emerg panic System is unusable A panic condition.
1 Alert alert   Action must be taken immediately A condition that should be corrected immediately, such as a corrupted system database.
2 Critical crit   Critical conditions Hard device errors.
3 Error err error Error conditions  
4 Warning warning warn Warning conditions  
5 Notice notice   Normal but significant conditions Conditions that are not error conditions, but that may require special handling.
6 Informational info   Informational messages  
7 Debug debug   Debug-level messages Messages that contain information normally of use only when debugging a program.

 

Logging only errors / timeouts / retries and errors is done with option:

Note that if the rsyslog is configured to listen on different port for some weird reason you should not forget to set the proper listen port, e.g.:
 

  log         127.0.0.1:514 local2 info

option dontlog-normal

in defaults or frontend section.

You most likely want to enable this only during certain times, such as when performing benchmarking tests.

(or log-format-sd for structured-data syslog) directive in your defaults or frontend
 

Haproxy Logging shortly explained


The type of logging you’ll see is determined by the proxy mode that you set within HAProxy. HAProxy can operate either as a Layer 4 (TCP) proxy or as Layer 7 (HTTP) proxy. TCP mode is the default. In this mode, a full-duplex connection is established between clients and servers, and no layer 7 examination will be performed. When in TCP mode, which is set by adding mode tcp, you should also add option tcplog. With this option, the log format defaults to a structure that provides useful information like Layer 4 connection details, timers, byte count and so on.

Below is example of configured logging with some explanations:

Log-format "%ci:%cp [%t] %ft %b/%s %Tw/%Tc/%Tt %B %ts %ac/%fc/%bc/%sc/%rc %sq/%bq"

haproxy-logged-fields-explained
Example of Log-Format configuration as shown above outputted of haproxy config:

Log-format "%ci:%cp [%tr] %ft %b/%s %TR/%Tw/%Tc/%Tr/%Ta %ST %B %CC %CS %tsc %ac/%fc/%bc/%sc/%rc %sq/%bq %hr %hs %{+Q}r"

haproxy_http_log_format-explained1

To understand meaning of this abbreviations you'll have to closely read  haproxy-log-format.txt. More in depth info is to be found in HTTP Log format documentation

 

Logging HTTP request headers

HTTP request header can be logged via:
 

 http-request capture

frontend website
    bind :80
    http-request capture req.hdr(Host) len 10
    http-request capture req.hdr(User-Agent) len 100
    default_backend webservers


The log will show headers between curly braces and separated by pipe symbols. Here you can see the Host and User-Agent headers for a request:

192.168.150.1:57190 [20/Dec/2018:22:20:00.899] website~ webservers/server1 0/0/1/0/1 200 462 – – —- 1/1/0/0/0 0/0 {mywebsite.com|Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Ubuntu Chromium/71.0.3578.80 } "GET / HTTP/1.1"

 

Haproxy Stats Monitoring Web interface


Haproxy is having a simplistic stats interface which if enabled produces some general useful information like in above screenshot, through which
you can get a very basic in browser statistics and track potential issues with the proxied traffic for all configured backends / frontends incoming outgoing
network packets configured nodes
 experienced downtimes etc.

haproxy-statistics-report-picture

The basic configuration to make the stats interface accessible would be like pointed in above config for example to enable network listener on address
 

https://192.168.0.5:8080/stats


with hproxyuser / password config would be:

# HAProxy Monitoring Config
#———————————————————————
listen stats 192.168.0.5:8080                #Haproxy Monitoring run on port 8080
    mode http
    option httplog
    option http-server-close
    stats enable
    stats show-legends
    stats refresh 5s
    stats uri /stats                            #URL for HAProxy monitoring
    stats realm Haproxy\ Statistics
    stats auth hproxyauser:Password___          #User and Password for login to the monitoring dashboard

 

 

Sessions states and disconnect errors on new application setup

Both TCP and HTTP logs include a termination state code that tells you the way in which the TCP or HTTP session ended. It’s a two-character code. The first character reports the first event that caused the session to terminate, while the second reports the TCP or HTTP session state when it was closed.

Here are some essential termination codes to track in for in the log:
 

Here are some termination code examples most commonly to see on TCP connection establishment errors:

Two-character code    Meaning
—    Normal termination on both sides.
cD    The client did not send nor acknowledge any data and eventually timeout client expired.
SC    The server explicitly refused the TCP connection.
PC    The proxy refused to establish a connection to the server because the process’ socket limit was reached while attempting to connect.


To get all non-properly exited codes the easiest way is to just grep for anything that is different from a termination code –, like that:

tail -f /var/log/haproxy.log | grep -v ' — '


This should output in real time every TCP connection that is exiting improperly.

There’s a wide variety of reasons a connection may have been closed. Detailed information about all possible termination codes can be found in the HAProxy documentation.
To get better understanding a very useful reading to haproxy Debug errors with  is in haproxy-logging.txt in that small file are collected all the cryptic error messages codes you might find in your logs when you're first time configuring the Haproxy frontend / backend and the backend application behind.

Another useful analyze tool which can be used to analyze Layer 7 HTTP traffic is halog for more on it just google around.

Procedure Instructions to safe upgrade CentOS / RHEL Linux 7 Core to latest release


February 13th, 2020

safe-upgrade-CentOS-and_Redhat_Enterprise_Linux_RHEL-7-to-latest-stable-release

Generally upgrading both RHEL and CentOS can be done straight with yum tool just we're pretty aware and mostly anyone could do the update, but it is good idea to do some
steps in advance to make backup of any old basic files that might help us to debug what is wrong in case if the Operating System fails to boot after the routine Machine OS restart
after the upgrade that is usually a good idea to make sure that machine is still bootable after the upgrade.

This procedure can be shortened or maybe extended depending on the needs of the custom case but the general framework should be useful anyways to someone that's why
I decided to post this.

Before you go lets prepare a small status script which we'll use to report status of  sysctl installed and enabled services as well as the netstat connections state and
configured IP addresses and routing on the system.

The script show_running_services_netstat_ips_route.sh to be used during our different upgrade stages:
 

# script status ###
echo "STARTED: $(date '+%Y-%m-%d_%H-%M-%S'):" | tee /root/logs/yumcheckupdate-$(hostname)-$(date '+%Y-%m-%d_%H-%M-%S').out
systemctl list-unit-files –type=service | grep enabled
systemctl | grep ".service" | grep "running"
netstat -tulpn
netstat -r
ip a s
/sbin/route -n
echo "ENDED $(date '+%Y-%m-%d_%H-%M-%S'):" | tee /root/logs/yumcheckupdate-$(hostname)-$(date '+%Y-%m-%d_%H-%M-%S').out
####

 

– Save the script in any file like /root/status.sh

– Make the /root/logs directoriy.
 

[root@redhat: ~ ]# mkdir /root/logs
[root@redhat: ~ ]# vim /root/status.sh
[root@redhat: ~ ]# chmod +x /root/status.sh

 

1. Get a dump of CentOS installed version release and grub-mkconfig generated os_probe

 

[root@redhat: ~ ]# cat /etc/redhat-release  > /root/logs/redhat-release-vorher-$(hostname)-$(date '+%Y-%m-%d_%H-%M-%S').out
[root@redhat: ~ ]# cat /etc/grub.d/30_os-prober > /root/logs/grub2-efi-vorher-$(hostname)-$(date '+%Y-%m-%d_%H-%M-%S').out

 

2. Clear old versionlock marked RPM packages (if there are such)

 

On servers maintained by multitude of system administrators just like the case is inside a Global Corporations and generally in the corporate world , where people do access the systems via LDAP and more than a single person
has superuser privileges. It is a good prevention measure to use yum package management  functionality to RPM based Linux distributions called  versionlock.
versionlock for those who hear it for a first time is locking the versions of the installed RPM packages so if someone by mistake or on purpose decides to do something like :

[root@redhat: ~ ]# yum install packageversion

Having the versionlock set will prevent the updated package to be installed with a different branch package version.

Also it will prevent a playful unknowing person who just wants to upgrade the system without any deep knowledge to be able to
run

[root@redhat: ~ ]# yum upgrade

update and leave the system in unbootable state, that will be only revealed during the next system reboot.

If you haven't used versionlock before and you want to use it you can do it with:

[root@redhat: ~ ]# yum install yum-plugin-versionlock

To add all the packages for compiling C code and all the interdependend packages, you can do something like:

 

[root@redhat: ~ ]# yum versionlock gcc-*

If you want to clear up the versionlock, once it is in use run:

[root@redhat: ~ ]#  yum versionlock clear
[root@redhat: ~ ]#  yum versionlock list

 

3.  Check RPC enabled / disabled

 

This step is not necessery but it is a good idea to check whether it running on the system, because sometimes after upgrade rpcbind gets automatically started after package upgrade and reboot. 
If we find it running we'll need to stop and mask the service.

 

# check if rpc enabled
[root@redhat: ~ ]# systemctl list-unit-files|grep -i rpc
var-lib-nfs-rpc_pipefs.mount                                      static
auth-rpcgss-module.service                                        static
rpc-gssd.service                                                  static
rpc-rquotad.service                                               disabled
rpc-statd-notify.service                                          static
rpc-statd.service                                                 static
rpcbind.service                                                   disabled
rpcgssd.service                                                   static
rpcidmapd.service                                                 static
rpcbind.socket                                                    disabled
rpc_pipefs.target                                                 static
rpcbind.target                                                    static

[root@redhat: ~ ]# systemctl status rpcbind.service
● rpcbind.service – RPC bind service
   Loaded: loaded (/usr/lib/systemd/system/rpcbind.service; disabled; vendor preset: enabled)
   Active: inactive (dead)

 

[root@redhat: ~ ]# systemctl status rpcbind.socket
● rpcbind.socket – RPCbind Server Activation Socket
   Loaded: loaded (/usr/lib/systemd/system/rpcbind.socket; disabled; vendor preset: enabled)
   Active: inactive (dead)
   Listen: /var/run/rpcbind.sock (Stream)
           0.0.0.0:111 (Stream)
           0.0.0.0:111 (Datagram)
           [::]:111 (Stream)
           [::]:111 (Datagram)

 

4. Check any previously existing downloaded / installed RPMs (check yum cache)

 

yum install package-name / yum upgrade keeps downloaded packages via its operations inside its cache directory structures in /var/cache/yum/*.
Hence it is good idea to check what were the previously installed packages and their count.

 

[root@redhat: ~ ]# cd /var/cache/yum/x86_64/;
[root@redhat: ~ ]# find . -iname '*.rpm'|wc -l

 

5. List RPM repositories set on the server

 

 [root@redhat: ~ ]# yum repolist
Loaded plugins: fastestmirror, versionlock
Repodata is over 2 weeks old. Install yum-cron? Or run: yum makecache fast
Determining fastest mirrors
repo id                                                                                 repo name                                                                                                            status
!atos-ac/7/x86_64                                                                       Atos Repository                                                                                                       3,128
!base/7/x86_64                                                                          CentOS-7 – Base                                                                                                      10,019
!cr/7/x86_64                                                                            CentOS-7 – CR                                                                                                         2,686
!epel/x86_64                                                                            Extra Packages for Enterprise Linux 7 – x86_64                                                                          165
!extras/7/x86_64                                                                        CentOS-7 – Extras                                                                                                       435
!updates/7/x86_64                                                                       CentOS-7 – Updates                                                                                                    2,500

 

This step is mandatory to make sure you're upgrading to latest packages from the right repositories for more concretics check what is inside in confs /etc/yum.repos.d/ ,  /etc/yum.conf 
 

6. Clean up any old rpm yum cache packages

 

This step is again mandatory but a good to follow just to have some more clearness on what packages is our upgrade downloading (not to mix up the old upgrades / installs with our newest one).
For documentation purposes all deleted packages list if such is to be kept under /root/logs/yumclean-install*.out file

[root@redhat: ~ ]# yum clean all |tee /root/logs/yumcleanall-$(hostname)-$(date '+%Y-%m-%d_%H-%M-%S').out

 

7. List the upgradeable packages's latest repository provided versions

 

[root@redhat: ~ ]# yum check-update |tee /root/logs/yumcheckupdate-$(hostname)-$(date '+%Y-%m-%d_%H-%M-%S').out

 

Then to be aware how many packages we'll be updating:

 

[root@redhat: ~ ]#  yum check-update | wc -l

 

8. Apply the actual uplisted RPM packages to be upgraded

 

[root@redhat: ~ ]# yum update |tee /root/logs/yumupdate-$(hostname)-$(date '+%Y-%m-%d_%H-%M-%S').out

 

Again output is logged to /root/logs/yumcheckupate-*.out 

 

9. Monitor downloaded packages count real time

 

To make sure yum upgrade is not in some hanging state and just get some general idea in which state of the upgrade is it e.g. Download / Pre-Update / Install  / Upgrade/ Post-Update etc.
in mean time when yum upgrade is running to monitor,  how many packages has the yum upgrade downloaded from remote RPM set repositories:

 

[root@redhat: ~ ]#  watch "ls -al /var/cache/yum/x86_64/7Server/…OS-repository…/packages/|wc -l"

 

10. Run status script to get the status again

 

[root@redhat: ~ ]# sh /root/status.sh |tee /root/logs/status-before-$(hostname)-$(date '+%Y-%m-%d_%H-%M-%S').out

 

11. Add back versionlock for all RPM packs

 

Set all RPM packages installed on the RHEL / CentOS versionlock for all packages.

 

#==if needed
# yum versionlock \*

 

 

12. Get whether old software configuration is not messed up during the Package upgrade (Lookup the logs for .rpmsave and .rpmnew)

 

During the upgrade old RPM configuration is probably changed and yum did automatically save .rpmsave / .rpmnew saves of it thus it is a good idea to grep the prepared logs for any matches of this 2 strings :
 

[root@redhat: ~ ]#   grep -i ".rpm" /root/logs/yumupdate-server-host-2020-01-20_14-30-41.out
[root@redhat: ~ ]#  grep -i ".rpmsave" /root/logs/yumupdate-server-host-2020-01-20_14-30-41.out
[root@redhat: ~ ]#  grep -i ".rpmnew" /root/logs/yumupdate-server-host-2020-01-20_14-30-41.out


If above commands returns output usually it is fine if there is is .rpmnew output but, if you get grep output of .rpmsave it is a good idea to review the files compare with the original files that were .rpmsaved with the 
substituted config file and atune the differences with the changes manually made for some program functionality.

What are the .rpmsave / .rpmnew files ?
This files are coded files that got triggered by the RPM install / upgrade due to prewritten procedures on time of RPM build.

 

If a file was installed as part of a rpm, it is a config file (i.e. marked with the %config tag), you've edited the file afterwards and you now update the rpm then the new config file (from the newer rpm) will replace your old config file (i.e. become the active file).
The latter will be renamed with the .rpmsave suffix.

If a file was installed as part of a rpm, it is a noreplace-config file (i.e. marked with the %config(noreplace) tag), you've edited the file afterwards and you now update the rpm then your old config file will stay in place (i.e. stay active) and the new config file (from the newer rpm) will be copied to disk with the .rpmnew suffix.
See e.g. this table for all the details. 

In both cases you or some program has edited the config file(s) and that's why you see the .rpmsave / .rpmnew files after the upgrade because rpm will upgrade config files silently and without backup files if the local file is untouched.

After a system upgrade it is a good idea to scan your filesystem for these files and make sure that correct config files are active and maybe merge the new contents from the .rpmnew files into the production files. You can remove the .rpmsave and .rpmnew files when you're done.


If you need to get a list of all .rpmnew .rpmsave files on the server do:

[root@redhat: ~ ]#  find / -print | egrep "rpmnew$|rpmsave$

 

13. Reboot the system 

To check whether on next hang up or power outage the system will boot normally after the upgrade, reboot to test it.

 

you can :

 

[root@redhat: ~ ]#  reboot

 

either

[root@redhat: ~ ]#  shutdown -r now


or if on newer Linux with systemd in ues below systemctl reboot.target.

[root@redhat: ~ ]#  systemctl start reboot.target

 

14. Get again the system status with our status script after reboot

[root@redhat: ~ ]#  sh /root/status.sh |tee /root/logs/status-after-$(hostname)-$(date '+%Y-%m-%d_%H-%M-%S').out

 

15. Clean up any versionlocks if earlier set

 

[root@redhat: ~ ]# yum versionlock clear
[root@redhat: ~ ]# yum versionlock list

 

16. Check services and logs for problems

 

After the reboot Check closely all running services on system make sure every process / listening ports and services on the system are running fine, just like before the upgrade.
If the sytem had firewall,  check whether firewall rules are not broken, e.g. some NAT is not missing or anything earlier configured to automatically start via /etc/rc.local or some other
custom scripts were run and have done what was expected. 
Go through all the logs in /var/log that are most essential /var/log/boot.log , /var/log/messages … yum.log etc. that could reveal any issues after the boot. In case if running some application server or mail server check /var/log/mail.log or whenever it is configured to log.
If the system runs apache closely check the logs /var/log/httpd/error.log or php_errors.log for any strange errors that occured due to some issues caused by the newer installed packages.
Usually most of the cases all this should be flawless but a multiple check over your work is a stake for good results.
 

Fix eth changing network interface names from new Linux naming scheme ens, eno, em1 to legacy eth0, eth1, eth2 on CentOS Linux


January 16th, 2020

Change-systemd-Linux-servers-network-interface-name-ensxx-to-eth0-copy

On CentOS / RHEL 7 / Fedora 19+ and other Linux distributions, the default network eth0, eth1 .. interface naming scheme has been changed and in newer Linux kernels OS-es to names such as – ens3 , eno1, enp5s2, em1 etc.,  well known old scheme for eth* is now considered a legacy.
This new Network card naming in Linux OS is due to changes made in Kernel / modules and udev  rules which resembles how Ethernet ifaces are named on other UNIX like systems.
The weird name is taken depending on the Hardware Network card vendor name and is a standard for years in FreeBSD and Mac OSX, however this was not so over the years,
so for old school sysadmins that's pretty annoying as, we're much used to the eth0 / eth1 / eth2 / eth3 naming standard which brought some clearness on the network card naming.

Also for systems which are upgraded from old Linux OS distro releases to a newer ones, that includes this great new "cool" feature, that fits so well the New age-of computing Cloud craziness.
That behaviour could create a number of problems, especially if the already Production working servers due to failure to bring up some of the network devices after the upgrade or, even if you fix that by editting the /etc/network* / etc/sysconfig/networking/* by hand still there is even more stuff that won't work properly, such as any custom made iptables / ipset firewalls rules, or any kind of custom used third party Shell / Perl scripts that depend on the old-school conventional and (convenient easy to remember!!!) eth0, eth2 etc. naming


For sysadmins who are using some kind of Application Clustering with something like corosync / pacemaker this new fuzzy improvement makes things even worse as having a changed interface name of the card will break the cluster …

 

1. Get list of the LAN Card Server hardware

 

To get a better view on the server installed and recognized LAN Cards use lspci / dmidecode commands:

 lspci |grep -i Ether -A1 -B1
01:00.4 USB controller: Hewlett-Packard Company Integrated Lights-Out Standard Virtual USB Controller (r                                                                                                           ev 03)
02:00.0 Ethernet controller: Broadcom Inc. and subsidiaries NetXtreme BCM5719 Gigabit Ethernet PCIe (rev                                                                                                            01)
02:00.1 Ethernet controller: Broadcom Inc. and subsidiaries NetXtreme BCM5719 Gigabit Ethernet PCIe (rev                                                                                                            01)
02:00.2 Ethernet controller: Broadcom Inc. and subsidiaries NetXtreme BCM5719 Gigabit Ethernet PCIe (rev                                                                                                            01)
02:00.3 Ethernet controller: Broadcom Inc. and subsidiaries NetXtreme BCM5719 Gigabit Ethernet PCIe (rev                                                                                                            01)
03:00.0 RAID bus controller: Hewlett-Packard Company Smart Array Gen9 Controllers (rev 01)
05:00.0 Ethernet controller: Broadcom Inc. and subsidiaries NetXtreme BCM5719 Gigabit Ethernet PCIe (rev                                                                                                            01)
05:00.1 Ethernet controller: Broadcom Inc. and subsidiaries NetXtreme BCM5719 Gigabit Ethernet PCIe (rev                                                                                                            01)
05:00.2 Ethernet controller: Broadcom Inc. and subsidiaries NetXtreme BCM5719 Gigabit Ethernet PCIe (rev                                                                                                            01)
05:00.3 Ethernet controller: Broadcom Inc. and subsidiaries NetXtreme BCM5719 Gigabit Ethernet PCIe (rev                                                                                                            01)
7f:08.0 System peripheral: Intel Corporation Xeon E7 v3/Xeon E5 v3/Core i7 QPI Link 0 (rev 02)

 

lspci reports all attached LAN Cards to server which are plugged in on the Motherbord, since that specific server has a Motherboard integrated LAN Adapters too, we can see this one
via dmidecode.

# dmidecode |grep -i Ether -A 5 -B 5

Handle 0x00C5, DMI type 41, 11 bytes
Onboard Device
        Reference Designation: Embedded LOM 1 Port 3
        Type: Ethernet
        Status: Enabled
        Type Instance: 3
        Bus Address: 0000:XX:00.X

Handle 0x00C6, DMI type 41, 11 bytes
Onboard Device
        Reference Designation: Embedded LOM 1 Port 4
        Type: Ethernet
        Status: Enabled
        Type Instance: 4
        Bus Address: 0000:0X:00.X

Handle 0x00C7, DMI type 41, 11 bytes


       Strings:
                PciRoot(0x0)/Pci(0x2,0x0)/Pci(0x0,0x0)
                NIC.Slot.2.1
                HP Ethernet 1Gb 4-port 331T Adapter – NIC
                Slot 2

Handle 0x00E3, DMI type 203, 34 bytes
OEM-specific Type
        Header and Data:

 

The illustrate the eth0 changing name issue, here is example taken from server on how eth1 interface is named on a new CentOS install:
 

# ip addr show

…..
eno1: [BROADCAST,MULTICAST,UP,LOWER_UP] mtu 1500 qdisc pfifo_fast state UP qlen 1000
link/ether 6c:0b:84:6c:48:1c brd ff:ff:ff:ff:ff:ff
inet 10.10.9.5/24 brd 10.10.9.255 scope global eno1
inet6 2606:b400:c00:48:6e0b:84ff:fe6c:481c/128 scope global dynamic
valid_lft 2326384sec preferred_lft 339184sec
inet6 fe80::6e0b:84ff:fe6c:481c/64 scope link
valid_lft forever preferred_lft forever

 

 

2. Disable Network Manager on the server


To prevent potential problems for future with randomly changing Network card names order on reboots and other mess,
it is generally a good idea to disable Network Manager.

 

# systemctl disable NetworkManager
rm '/etc/systemd/system/multi-user.target.wants/NetworkManager.service'
rm '/etc/systemd/system/dbus-org.freedesktop.NetworkManager.service'
rm '/etc/systemd/system/dbus-org.freedesktop.nm-dispatcher.service'

 

3. Check and correct network configuration if necessery in  /etc/sysconfig/network-scripts/ifcfg-*


Either fix the naming across all files ifcfg-* to match eth0 / eth1 / ethXX or even better both change the NAME and DEVICE in files and completely rename the files ifcfg-eno1 to ifcfg-eth1 ..
ifcfg-enoXX to ifcfg-ethXX
 

server:~# cat /etc/sysconfig/network-scripts/ifcfg-eno1
……
NAME=eth0
DEVICE=eth0
……

 

4. Fix the interface scheme naming through passing a GRUB boot parameter to Kernel

 

a. Create backup of /etc/default/grub
 

cp -rpf /etc/default/grub /etc/default/grub_bak_date +"%Y_%m_%Y"


b. Edit /etc/default/grub

c. Find config parameter GRUB_CMDLINE_LINUX

d. Add net.ifnames=0 biosdevname=0 to the line

 

net.ifnames=0 biosdevname=0


After the change the line should look like

GRUB_CMDLINE_LINUX=" crashkernel=auto net.ifnames=0 biosdevname=0 rhgb quiet"

 

e. Regenerate GRUB loader to have included the new config

server:~# grub2-mkconfig -o /boot/grub2/grub.cfg

f. Reboot the sytem
 

server:~# shutdown -r now

 

5. Fix auto-generated inconvenient naming by modifying udev rules

The Mellanox Ehternet server card vendor's workaround to the ever changing eth names is modify udev rules to be able to have the ordinary eth0 / eth1 / eth2 … Lan card name scheme.
In short this is recommended for Mellanox but should work on any other Lan card device attached on a Linux powered server.
 

# cat /etc/sysconfig/network-scripts/ifcfg-eth1
DEVICE="eth1"
BOOTPROTO="static"
HWADDR="7c:fe:90:cb:76:02"
IPADDR=10.10.9.2
NETMASK=255.255.255.0
ONBOOT="yes"

 

# cat /etc/sysconfig/network-scripts/ifcfg-eth2
DEVICE="eth1"
BOOTPROTO="static"
HWADDR="7c:fe:90:cb:76:02"
IPADDR=10.10.99.99
NETMASK=255.255.255.0
ONBOOT="yes"

 

# vi /etc/udev/rules.d/70-persistent-net.rules

SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", ATTR{address}=="7c:fe:90:cb:76:02", ATTR{dev_id}=="0x0", ATTR{type}=="1", KERNEL=="eth*", NAME="eth1"

SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", ATTR{address}=="7c:fe:90:cb:76:03", ATTR{dev_id}=="0x0", ATTR{type}=="1", KERNEL=="eth*", NAME="eth2"

 

Next step is to reboot.
 

# /sbin/reboot


After a while when the server boots check with ip or ifconfig the configuration to make sure the ethXX ordering is proper again.

interface-list-eth1-eth2-screenshot

# /sbin/ifconfig eth1
eth1: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 10.0.99.99 netmask 255.255.255.0 broadcast 10.10.9.255
inet6 fe80::7efe:90ff:fecb:7602 prefixlen 64 scopeid 0x20<link>
ether 7c:fe:90:cb:76:02 txqueuelen 1000 (Ethernet)
RX packets 0 bytes 0 (0.0 B)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 23 bytes 3208 (3.1 KiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
eth2: flags=4099<UP,BROADCAST,MULTICAST> mtu 1500
ether 7c:fe:90:cb:76:03 txqueuelen 1000 (Ethernet)
RX packets 0 bytes 0 (0.0 B)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 0 bytes 0 (0.0 B)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0

On some Linux distributions, if it happens this udev extra configuration is not venerated, use net.ifnames=0 biosdevname=0 grub configuration.

6. Verify eth interfaces are present    

# ip addr show

…..

eth0: [BROADCAST,MULTICAST,UP,LOWER_UP] mtu 1500 qdisc pfifo_fast state UP qlen 1000

link/ether 6c:0b:84:6c:48:1c brd ff:ff:ff:ff:ff:ff

inet 10.10.9.5/24 brd 10.10.9.255 scope global eno1

inet6 2606:b400:c00:48:6e0b:84ff:fe6c:481c/128 scope global dynamic

valid_lft 2326384sec preferred_lft 339184sec

inet6 fe80::6e0b:84ff:fe6c:481c/64 scope link

valid_lft forever preferred_lft forever

That's all this should put an end to the annoying auto generated naming lan device naming.

 

Summary

 

So what was explained up was how to resolve problems caused by autogenerated ethernet interface cards by a new functionality in the Linux kernel, so Network cards are again visible via ip address show / ifconfig again in a proper order eth0 / eth1 / eth2 / eth3 etc. instead of a vendor generated cryptic names as ens / eno / em etc. This is possible via either by editing udev rules or grub configuration. Doing so saves nerves and makes sysadmin life better, at least it did mine.
That's all this should put an end to the annoying auto generated naming.
 

How to debug failing service in systemctl and add a new IP network alias in CentOS Linux


January 15th, 2020

linux-debug-failing-systemctl-systemd-service--add-new-IP-alias-network-cable

If you get some error with some service that is start / stopped via systemctl you might be pondering how to debug further why the service is not up then then you'll be in the situation I was today.
While on one configured server with 8 eth0 configured ethernet network interfaces the network service was reporting errors, when atempted to restart the RedHat way via:
 

service network restart


to further debug what the issue was as it was necessery I had to find a way how to debug systemctl so here is how:

 

How to do a verbose messages status for sysctlct?

 

linux:~# systemctl status network

linux:~# systemctl status network

 

Another useful hint is to print out only log messages for the current boot, you can that with:

# journalctl -u service-name.service -b

 

if you don't want to have the less command like page separation ( paging ) use the –no-pager argument.

 

# journalctl -u network –no-pager

Jan 08 17:09:14 lppsq002a network[8515]: Bringing up interface eth5:  [  OK  ]

    Jan 08 17:09:15 lppsq002a network[8515]: Bringing up interface eth6:  [  OK  ]
    Jan 08 17:09:15 lppsq002a network[8515]: Bringing up interface eth7:  [  OK  ]
    Jan 08 17:09:15 lppsq002a systemd[1]: network.service: control process exited, code=exited status=1
    Jan 08 17:09:15 lppsq002a systemd[1]: Failed to start LSB: Bring up/down networking.
    Jan 08 17:09:15 lppsq002a systemd[1]: Unit network.service entered failed state.
    Jan 08 17:09:15 lppsq002a systemd[1]: network.service failed.
    Jan 15 11:04:45 lppsq002a systemd[1]: Starting LSB: Bring up/down networking…
    Jan 15 11:04:45 lppsq002a network[55905]: Bringing up loopback interface:  [  OK  ]
    Jan 15 11:04:45 lppsq002a network[55905]: Bringing up interface eth0:  RTNETLINK answers: File exists
    Jan 15 11:04:45 lppsq002a network[55905]: [  OK  ]
    Jan 15 11:04:45 lppsq002a network[55905]: Bringing up interface eth1:  RTNETLINK answers: File exists
    Jan 15 11:04:45 lppsq002a network[55905]: [  OK  ]
    Jan 15 11:04:46 lppsq002a network[55905]: Bringing up interface eth2:  ERROR     : [/etc/sysconfig/network-scripts/ifup-eth] Device eth2 has different MAC address than expected, ignoring.
    Jan 15 11:04:46 lppsq002a network[55905]: [FAILED]
    Jan 15 11:04:46 lppsq002a network[55905]: Bringing up interface eth3:  RTNETLINK answers: File exists
    Jan 15 11:04:46 lppsq002a network[55905]: [  OK  ]
    Jan 15 11:04:46 lppsq002a network[55905]: Bringing up interface eth4:  ERROR     : [/etc/sysconfig/network-scripts/ifup-eth] Device eth4 does not seem to be present, delaying initialization.
    Jan 15 11:04:46 lppsq002a network[55905]: [FAILED]
    Jan 15 11:04:46 lppsq002a network[55905]: Bringing up interface eth5:  RTNETLINK answers: File exists
    Jan 15 11:04:46 lppsq002a network[55905]: [  OK  ]
    Jan 15 11:04:46 lppsq002a network[55905]: Bringing up interface eth6:  RTNETLINK answers: File exists
    Jan 15 11:04:47 lppsq002a network[55905]: [  OK  ]
    Jan 15 11:04:47 lppsq002a network[55905]: Bringing up interface eth7:  RTNETLINK answers: File exists
    Jan 15 11:04:47 lppsq002a network[55905]: [  OK  ]
    Jan 15 11:04:47 lppsq002a network[55905]: RTNETLINK answers: File exists
    Jan 15 11:04:47 lppsq002a network[55905]: RTNETLINK answers: File exists
    Jan 15 11:04:47 lppsq002a network[55905]: RTNETLINK answers: File exists
    Jan 15 11:04:47 lppsq002a network[55905]: RTNETLINK answers: File exists
    Jan 15 11:04:47 lppsq002a network[55905]: RTNETLINK answers: File exists
    Jan 15 11:04:47 lppsq002a network[55905]: RTNETLINK answers: File exists
    Jan 15 11:04:47 lppsq002a network[55905]: RTNETLINK answers: File exists
    Jan 15 11:04:47 lppsq002a network[55905]: RTNETLINK answers: File exists
    Jan 15 11:04:47 lppsq002a network[55905]: RTNETLINK answers: File exists
    Jan 15 11:04:47 lppsq002a systemd[1]: network.service: control process exited, code=exited status=1
    Jan 15 11:04:47 lppsq002a systemd[1]: Failed to start LSB: Bring up/down networking.
    Jan 15 11:04:47 lppsq002a systemd[1]: Unit network.service entered failed state.
    Jan 15 11:04:47 lppsq002a systemd[1]: network.service failed.
    Jan 15 11:08:22 lppsq002a systemd[1]: Starting LSB: Bring up/down networking…
    Jan 15 11:08:22 lppsq002a network[56841]: Bringing up loopback interface:  [  OK  ]
    Jan 15 11:08:22 lppsq002a network[56841]: Bringing up interface eth0:  RTNETLINK answers: File exists
    Jan 15 11:08:22 lppsq002a network[56841]: [  OK  ]
    Jan 15 11:08:26 lppsq002a network[56841]: Bringing up interface eth1:  RTNETLINK answers: File exists
    Jan 15 11:08:26 lppsq002a network[56841]: [  OK  ]
    Jan 15 11:08:26 lppsq002a network[56841]: Bringing up interface eth2:  ERROR     : [/etc/sysconfig/network-scripts/ifup-eth] Device eth2 has different MAC address than expected, ignoring.
    Jan 15 11:08:26 lppsq002a network[56841]: [FAILED]
    Jan 15 11:08:26 lppsq002a network[56841]: Bringing up interface eth3:  RTNETLINK answers: File exists
    Jan 15 11:08:27 lppsq002a network[56841]: [  OK  ]


2020-01-15-15_42_11-root-server

 

Another useful thing debug arguments is the -xe to do:

# journalctl -xe –no-pager

 

  • -x (– catalog)
    Augment log lines with explanation texts from the message catalog.
    This will add explanatory help texts to log messages in the output
    where this is available.
  •  -e ( –pager-end )  Immediately jump to the end of the journal inside the implied pager
      tool.

2020-01-15-15_42_32-root-server

Finally after fixing the /etc/sysconfig/networking-scripts/* IP configuration issues I had all the 8 Ethernet interfaces to work as expected
 

# systemctl status network


2020-01-15-16_15_38-root-server

 

 

2. Adding a new IP alias to eth0 interface


Further on I had  to add an IP Alias on the CenOS via its networking configuration, this is done by editing /etc/sysconfig/network-scripts/ifcfg* files.
To create an IP alias for first lan interface eth0, I've had to created a new file named ifcfg-eth0:0
 

linux:~# cd /etc/sysconfig/network-scripts/
linux:~# vim ifcfg-eth0:0


with below content

NAME="eth0:0"
ONBOOT="yes"
BOOTPROTO="none"
IPADDR="10.50.10.5"
NETMASK="255.255.255.0"


Adding this IP address network alias works across all RPM based distributions and should work also on Fedora and Open SuSE as well as Suse Enterprise Linux.
If you however prefer to use a text GUI and do it the CentOS server administration way you can use nmtui (Text User Interface for controlling NetworkManager). tool.
 

linux:~# nmtui

 

centos7_nmtui-ncurses-network-configuration-sysadmin-tool

nmtui_add_alias_interface-screenshot

How to install jcmd on CentOS 7 to diagnose running Java Virtual Machine crashing applications


January 14th, 2020

how-to-install-jcmd-centos-jcdm-java-logo-1

jcmd utility is well known in the Brane New wonderful world of Java but if you're like me a classical old school sysadmins and non-java developer you probably never heard it hence before going straight into how to install it on CentOS 7 Linux servers, I'll shortly say few words on what it is.
jcmd is used to send diagnostic requests to running Java Virtual Machine (JVM) it is available in both in Oracle Java as well as OpenJDK.
The requests jcmd sends to VM are based on the running Java PID ID and are pretty useful for controlling Java Flight Recordings, troubleshoot, and diagnose JVM and Java Applications. It must be used on the same machine where the JVM is running.

 Used without arguments or with the -l option, jcmd prints the list of running Java processes with their process id, their main class and their command line arguments.
When a main class is specified on the command line, jcmd sends the diagnostic command request to all Java processes for which the command line argument is a substring of the Java process' main class.
jcmd could be useful if the JConsoleJMX (Java Management Extensions) can't be used for some reason on the server or together with Java Visual VM (visual interface for viewing detailed info about Java App).

In most Linux distributionsas as  of year 2020 jcmd is found in  java-*-openjdk-headless.

To have jcmd on lets say Debian GNU / Linux, you're up to something like:

 

apt-get install –yes openjdk-12-jdk-headless
 

or

apt-get install openjdk-11-jdk-headless
however in CentOS
7 jcmd is not found in java*openjdk*headless but instead to have it on server, thus it take me a while to look up where it is foundso after hearing
from some online post it is part of package java*openjdk*devel* to make sure this so true, I've used the  –download-only option
 

 yum install –downloadonly –downloaddir=/tmp java-1.8.0-openjdk-devel

 


So the next question was how to inspect the downloaded rpm package into /tmp usually, this is possible via Midnight Commander (mc) easily to view contents, however as this
server did not have installed mc due to security policies I had to do it differently after pondering a while on how to to list the RPM package file content come up using following command

 

 

 rpm2cpio java-1.8.0-openjdk-devel-1.8.0.232.b09-0.el7_7.x86_64.rpm |cpio -idmv|grep -i jcmd|less

 


To then install  java-1.8.0-openjdk-devel-1.8.0.232.b09-0.el7_7.x86_64.rpm to do so run:

 

 

 

yum -y install  java-1.8.0-openjdk-devel-1.8.0*


Once the jcmd, I've created the following bash script  that was set that was tracking for application errors and checking whether the JBoss application server pool-available-count is not filled up and hence jboss refuses to serve connections  through jboss-cli.sh query automatically launching jcmd to get various diagnostic data about Java Virtual Machine (e.g. a running snapshot) – think of it like the UNIX top for debugging or Windows System Monitor but run one time. 

 

 

 

# PID_OF_JAVA=$(pgrep -l java)
# jcmd $PID_OF_JAVA GC.heap_dump GC.heap_dump_file-$(date '+%Y-%m-%d_%H-%M-%S').jfr
# jcmd $PID_OF_JAVA Thread.print > Thread.print-$(date '+%Y-%m-%d_%H-%M-%S').jfr


The produced log files can then be used by the developer to visualize some Java specific stuff "Flight recordings" like in below screenshot:

jcmd-java-tool-dump-jfr-flight-recordings-visualized-java 

If you're interested on some other interesting tools that can be used to Monitor  and Debug a Running Java VM take a look at Java's official documentation Monitoring Tools.
So that's all Mission Accomplished 🙂 Now the Java Application developer could observe the log and tell why exactly the application crashed after the multitude of thrown Exceptions in the JBoss server.log.

Linux show largest sized packages / Which Deb, RPM Linux installed package use most disk space and How to Free Space for critical system updates


January 12th, 2020

linux-show-largest-sized-packages-which-deb-rpm-linux-package-use-most-disk-space-to-free-space-for-critical-system-updates

A very common problem that happens on both Linux installed servers and Desktop Linux is a starting to fill / (root partition). This problem could happen due to several reasons just to point few of them out of my experience low disk space (ending free space) could be due to:

– Improper initial partitioning / bad space planning / or OS install made in a hurry (due to time constrains)
– Linux installed on old laptop machine with low Hard Disk Drive capacity (e.g. 80 Giga / 160 GB)
– Custom user partitioning on install time aiming for a small root partition originally and changing space requirements in time
– Due to increasing space taken by Linux updates / user stored files etc / distribution OS Level upgrades dist-upgrades.
– Improperly assigned install time partitions cause of lack of knowledge to understand how partitioning is managed.
– Due to install being made in a hurry

– Linux OS installed on a Cloud based VPN (e.g. running) in a Cloud Instance that is hosted in Amazon EC2, Linode, Digital Ocean, Hostgator etc.

So here is a real time situation that happened me many times, you're launching an apt-get upgrade / apt-get dist-upgrade or yum upgrade the packages are about to start downloading or downloaded and suddenly you get a message of not enough disk space to apply OS package updates …
That's nasty stuff mostly irritating and here there are few approaches to take.

a. perhaps easiest you can ofcourse extend the partition (with a free spaced other Primary or Extended partition) with something like:

parted (the disk partitioning manipulator for Linux), gparted (in case if Desktop with GUI / XOrg server running)

b. if not enough space on the Hard Disk Drive or SSD (Solid State Drive) and you have a budget to buy and free laptop / PC slot to place another physical HDD to clone it to a larger sized HDD and use some kind of partition clone tool, such as:

or any of the other multiple clone tools available in Linux.

But what if you don't have the option for some reason to extend the paritiotn, how can you apply the Critical Security Errata Updates issued to patch security vulnerabilities reported by well known CVEs?
Well you can start with the obvious easy you can start removing unnecessery stuff from the system (if home is also stored on the / – root partiiton) to delete something from there, even delete the /usr/local/man pages if you don't plan to read it free some logs by archiving purging logs from /var/log/* …

But if this is not possible, a better approach is simply try to remove / purge any .deb / .rpm whatever distro package manager packages that are not necessery used and just hanging around, that is often the case especially on Linux installed on Notebooks for a personal home use, where with years you have installed a growing number of packages which you don't actively use but installed just to take a look, while hunting for Cool Linux games and you wanted to give a try to Battle of Wesnoth  / FreeCIV / AlienArena / SuperTux Kart / TuxRacer etc.  or some GUI heavy programs like Krita / Inskape / Audacity etc.

To select which package might be not needed and just takes space hence you need to to list all installed packages on the system ordered by their size this is different in Debian based Linuces e.g. – Debian GNU / Linux / Ubuntu / Mint etc. and RPM based ones Fedora / CentOS / OpenSuSE

 

1. List all RPM installed packages by Size on CentOS / SuSE
 

Finding how much space each of the installed rpm packages take on the HDD and displaying them in a sorted order is done with:

rpm -qa –queryformat '%10{size} – %-25{name} \t %{version}\n' | sort -n

From the command above,  the '%10{size}' option aligns the size of the package to the right with a padding of 10 characters. The '%-25{name} aligns the name of the package to the left, padded to 25 characters. The '%{version} indicates the version and 'sort -n' flag sorts the packages according to size from the smallest to the largest in bytes.

 

2. List all installed RPM packages sorted by size on Fedora

Fedora has introduced the dnf package manager instead of yum, to get how much size individual rpm package occupies on system:

dnf info samba
Available Packages
Name        : samba
Arch        : x86_64
Epoch       : 2
Version     : 4.1.20
Release     : 1.fc21
Size        : 558 k
Repo        : updates
Summary     : Server and Client software to interoperate with Windows machines
URL         : http://www.samba.org/
License     : GPLv3+ and LGPLv3+
Description : Samba is the standard Windows interoperability suite of programs
            : for Linux and Unix.

 

To get a list of all packages on system with their size

dnf info * | grep -i "Installed size" |sort -n

 

3. List all installed DEB packages on Debian / Ubuntu / Mint etc. with dpkg / aptitude / apt-get and wajig

 

The most simple way to get a list of largest packages is through dpkg

 

# dpkg-query -Wf '${Installed-Size}\t${Package}\n' | sort -n
        brscan4
6       default-jre
6       libpython-all-dev
6       libtinfo-dev
6       python-all
6       python-all-dev
6       task-cinnamon-desktop
6       task-cyrillic
6       task-desktop
6       task-english
6       task-gnome-desktop
6       task-laptop
6       task-lxde-desktop
6       task-mate-desktop
6       task-print-server
6       task-ssh-server
6       task-xfce-desktop
8       mysql-client
8       printer-driver-all



207766    libwine
215625    google-chrome-stable
221908    libwine
249401    frogatto-data
260717    linux-image-4.19.0-5-amd64
262512    linux-image-4.19.0-6-amd64
264899    mame
270589    fonts-noto-extra
278903    skypeforlinux
480126    metasploit-framework


above cmd displays packages in size order, largest package last, but the output will include also size of packages, that used to exist,
have been removed but was not purged. Thus if you find  a package that is shown as very large by size but further dpkg -l |grep -i package-name shows package as purged e.g. package state is not 'ii' but 'rc', the quickest work around is to purge all removed packages, that are still not purged and have some configuration remains and other chunks of data that just take space for nothing with:

# dpkg –list |grep "^rc" | cut -d " " -f 3 | xargs sudo dpkg –purge


Be cautious when you execute above command, because if for some reason you uninstalled a package with the idea to keep old configuration files only and in case if you decide to use it some time in future to reuse already custom made configs but do run above purge commands all such package saved kept configs will disappear.
For people who don't want to mess up with, uninstalled but present packages use this to filter out ready to be purged state packages.

# dpkg-query -Wf '${db:Status-Status} ${Installed-Size}\t${Package}\n' | sed -ne 's/^installed //p'|sort -n


aptitude – (high level ncurses interface like to package management) can also be easily used to list largest size packages eating up your hard drive in both interactive or cli mode, like so:

 

# aptitude search –sort '~installsize' –display-format '%p %I' '~i' | head
metasploit-framework 492 MB
skypeforlinux 286 MB
fonts-noto-extra 277 MB
mame 271 MB
linux-image-4.19.0-6-amd64 269 MB
linux-image-4.19.0-5-amd64 267 MB
frogatto-data 255 MB
libwine 227 MB
google-chrome-stable 221 MB
libwine:i386 213 MB

 

  • –sort is package sort order, and ~installsize specifies a package sort policy.
  • installsize means 'sort on (estimated) installed size', and the preceding ~ means sort descending (since default for all sort policies is ascending).
  • –display-format changes the <you guessed :->. The format string '%p %I' tells aptitude to output package name, then installed size.
  • '~i' tells aptitude to search only installed packages.

How much a certain .deb package removal will free up on the disk can be seen with apt-get as well to do so for the famous 3D acceleration Graphic Card (enabled) or not  test game extremetuxracer

apt-get –assume-no –purge remove "texlive*" | grep "be freed" | 
   awk '{print $4, $5}'

Perhaps,  the easiest to remember and more human readable output biggest packages occupied space on disk is to install and use a little proggie called wajig to do so

 

# apt install –yes wajig

 

Here is how to pick up 10 biggest size packages.

root@jeremiah:/home/hipo# wajig large|tail -n 10
fonts-noto-cjk-extra               204,486      installed
google-chrome-stable               215,625      installed
libwine                            221,908      installed
frogatto-data                      249,401      installed
linux-image-4.19.0-5-amd64         260,717      installed
linux-image-4.19.0-6-amd64         262,512      installed
mame                               264,899      installed
fonts-noto-extra                   270,589      installed
skypeforlinux                      278,903      installed
metasploit-framework               480,126      installed


As above example lists a short package name and no description for those who want get more in depth knowledge on what exactly is the package bundle used for use:

# aptitude search –sort '~installsize' –display-format '%30p %I %r %60d' '~i' |head


%30p %I %r %60d display more information in your format string, or change field widths, enhanced format string

Meaning of parameters is:

  • %30p : package name in field width=30 char
  • %I : estimated install size
  • %r : 'reverse depends count': approximate number of other installed packages which depend upon this package
  • %60d : package's short description in field width=60 char

wajig is capable is a python written and idea is to easify Debian console package management (so you don't have to all time remember when and with which arguments to use apt-get / apt-cache etc.), below is list of commands it accepts.

 

root@jeremiah:/home/hipo## wajig commands
addcdrom           Add a Debian CD/DVD to APT's list of available sources
addrepo            Add a Launchpad PPA (Personal Package Archive) repository
aptlog             Display APT log file
autoalts           Mark the Alternative to be auto-set (using set priorities)
autoclean          Remove no-longer-downloadable .deb files from the download cache
autodownload       Do an update followed by a download of all updated packages
autoremove         Remove unused dependency packages
build              Get source packages, unpack them, and build binary packages from them.
builddeps          Install build-dependencies for given packages
changelog          Display Debian changelog of a package
clean              Remove all deb files from the download cache
contents           List the contents of a package file (.deb)
dailyupgrade       Perform an update then a dist-upgrade
dependents         Display packages which have some form of dependency on the given package
describe           Display one-line descriptions for the given packages
describenew        Display one-line descriptions of newly-available packages
distupgrade        Comprehensive system upgrade
download           Download one or more packages without installing them
editsources        Edit list of Debian repository locations for packages
extract            Extract the files from a package file to a directory
fixconfigure       Fix an interrupted install
fixinstall         Fix an install interrupted by broken dependencies
fixmissing         Fix and install even though there are missing dependencies
force              Install packages and ignore file overwrites and depends
hold               Place packages on hold (so they will not be upgraded)
info               List the information contained in a package file
init               Initialise or reset wajig archive files
install            Package installer
installsuggested   Install a package and its Suggests dependencies
integrity          Check the integrity of installed packages (through checksums)
large              List size of all large (>10MB) installed packages
lastupdate         Identify when an update was last performed
listall            List one line descriptions for all packages
listalternatives   List the objects that can have alternatives configured
listcache          List the contents of the download cache
listcommands       Display all wajig commands
listdaemons        List the daemons that wajig can start, stop, restart, or reload
listfiles          List the files that are supplied by the named package
listhold           List packages that are on hold (i.e. those that won't be upgraded)
listinstalled      List installed packages
listlog            Display wajig log file
listnames          List all known packages; optionally filter the list with a pattern
listpackages       List the status, version, and description of installed packages
listscripts        List the control scripts of the package of deb file
listsection        List packages that belong to a specific section
listsections       List all available sections
liststatus         Same as list but only prints first two columns, not truncated
localupgrade       Upgrade using only packages that are already downloaded
madison            Runs the madison command of apt-cache
move               Move packages in the download cache to a local Debian mirror
new                Display newly-available packages
newdetail          Display detailed descriptions of newly-available packages
news               Display the NEWS file of a given package
nonfree            List packages that don't meet the Debian Free Software Guidelines
orphans            List libraries not required by any installed package 
policy             From preferences file show priorities/policy (available)
purge              Remove one or more packages and their configuration files
purgeorphans       Purge orphaned libraries (not required by installed packages)
purgeremoved       Purge all packages marked as deinstall
rbuilddeps         Display the packages which build-depend on the given package
readme             Display the README file(s) of a given package
recdownload        Download a package and all its dependencies
recommended        Display packages installed as Recommends and have no dependents
reconfigure        Reconfigure package
reinstall          Reinstall the given packages
reload             Reload system daemons (see LIST-DAEMONS for available daemons)
remove             Remove packages (see also PURGE command)
removeorphans      Remove orphaned libraries
repackage          Generate a .deb file from an installed package
reportbug          Report a bug in a package using Debian BTS (Bug Tracking System)
restart            Restart system daemons (see LIST-DAEMONS for available daemons)
rpm2deb            Convert an .rpm file to a Debian .deb file
rpminstall         Install an .rpm package file
search             Search for package names containing the given pattern
searchapt          Find nearby Debian package repositories
show               Provide a detailed description of package
sizes              Display installed sizes of given packages
snapshot           Generates a list of package=version for all installed packages
source             Retrieve and unpack sources for the named packages
start              Start system daemons (see LIST-DAEMONS for available daemons)
status             Show the version and available versions of packages
statusmatch        Show the version and available versions of matching packages
stop               Stop system daemons (see LISTDAEMONS for available daemons)
tasksel            Run the task selector to install groups of packages
todo               Display the TODO file of a given package
toupgrade          List versions of upgradable packages
tutorial           Display wajig tutorial
unhold             Remove listed packages from hold so they are again upgradeable
unofficial         Search for an unofficial Debian package at apt-get.org
update             Update the list of new and updated packages
updatealternatives Update default alternative for things like x-window-manager
updatepciids       Updates the local list of PCI ids from the internet master list
updateusbids       Updates the local list of USB ids from the internet master list
upgrade            Conservative system upgrade
upgradesecurity    Do a security upgrade
verify             Check package's md5sum
versions           List version and distribution of given packages
whichpackage       Search for files matching a given pattern within packages

 

4. List installed packages order by size in Arch Linux

ArchLinux is using the funny named package manager – pacman (a nice prank for the good old arcade game).
What is distinctive of pacman uses libalpm (Arch Linux Package Management (ALPM) library) as a back-end to perform all the actions.

 

# pacman -Qi | awk '/^Name/{name=$3} /^Installed Size/{print $4$5, name}' | sort -hr | head -25
296.64MiB linux-firmware
144.20MiB python
105.43MiB gcc-libs
72.90MiB python2
66.91MiB linux
57.47MiB perl
45.49MiB glibc
35.33MiB icu
34.68MiB git
30.96MiB binutils
29.95MiB grub
18.96MiB systemd
13.94MiB glib2
13.79MiB coreutils
13.41MiB python2-boto
10.65MiB util-linux
9.50MiB gnupg
8.09MiB groff
8.05MiB gettext
7.99MiB texinfo
7.93MiB sqlite
7.15MiB bash
6.50MiB lvm2
6.43MiB openssl
6.33MiB db


There is another mean to list packages by size using a ArchLinux tool called pacgraph
 

 

# pacgraph -c | head -25

Autodetected Arch.
Loading package info
Total size: 1221MB
367MB linux
144MB pacgraph
98MB cloud-init
37MB grub
35MB icu
34MB git
31698kB binutils
19337kB pacman
11029kB man-db
8186kB texinfo
8073kB lvm2
7632kB nano
7131kB openssh
5735kB man-pages
3815kB xfsprogs
3110kB sudo
3022kB wget
2676kB tar
2626kB netctl
1924kB parted
1300kB procps-ng
1248kB diffutils

 

 

 

4. Debian Goodies

 

 

Most debian users perhaps never hear of debian-goodies package, but I thought it is worthy to mention it as sooner or later as a sysadmin or .deb based Desktop user it might help you somewhere.
 

Debian-goodies is sall toolbox-style utilities for Debian systems
 These programs are designed to integrate with standard shell tools,
 extending them to operate on the Debian packaging system.

 .
  dglob  – Generate a list of package names which match a pattern
           [dctrl-tools, apt*, apt-file*, perl*]
  dgrep  – Search all files in specified packages for a regex
           [dctrl-tools, apt-file (both via dglob)]
 .
 These are also included, because they are useful and don't justify
 their own packages:
 .
  check-enhancements
 
           – find packages which enhance installed packages [apt,
                dctrl-tools]
  checkrestart
 
           – Help to find and restart processes which are using old versions
               of upgraded files (such as libraries) [python3, procps, lsof*]
  debget     – Fetch a .deb for a package in APT's database [apt]
  debman     – Easily view man pages from a binary .deb without extracting
               [man, apt* (via debget)]
  debmany    – Select manpages of installed or uninstalled packages [man |
               sensible-utils, whiptail | dialog | zenity, apt*, konqueror*,
               libgnome2-bin*, xdg-utils*]
  dhomepage  – Open homepage of a package in a web browser [dctrl-tools,
               sensible-utils*, www-browser* | x-www-browser*]
  dman       – Fetch manpages from online manpages.debian.org service [curl,
               man, lsb-release*]
  dpigs      – Show which installed packages occupy the most space
               [dctrl-tools]
  find-dbgsym-packages
             – Get list of dbgsym packages from core dump or PID [dctrl-tools,
               elfutils, libfile-which-perl, libipc-system-simple-perl]
  popbugs    – Display a customized release-critical bug list based on
               packages you use (using popularity-contest data) [python3,
               popularity-contest]
  which-pkg-broke
             – find which package might have broken another [python3, apt]
  which-pkg-broke-build
             – find which package might have broken the build of another
               [python3 (via which-pkg-broke), apt]

Even simpler by that is to use dpigs shell script part of the debian-goodies package which will automatically print out the largest packages.

dpigs command output is exactly the same as 'dpkg-query -Wf '${Installed-Size}\t${Package}\n' | sort -nr | head', but is useful cause you don't have to remember that complex syntax.

 

5. Checking where your space is gone in a Spacesniffer like GUI manner with Baobab


In my prior article Must have software on a new installed Windows 2 of the  of the precious tools to set are Spacesniffer and WinDirStat.
Windows users will be highly delighted to know that SpaceSniffer equivallent is already present on Linux – say hello baobab.
Baobab
is simple but useful Graphic disk usage overview program for those who don't want to mess to much with the console / terminal to find out which might be the possible directory candidate for removal. It is very simplistic but it does well what it is aimed for, to install it on a Debian or .deb based OS.

# apt install –yes baobab


baobab-entry-screen-debian-gnu-linux-screenshot

baobab Linux Hard Disk Usage Analyzer for GNOME. – It can easily scan either the whole filesystem or a specific user-requested branch (Iocal or remote)

 

baobab-entry-screen-debian-gnu-linux-directories-taking-most-space-pie-screenshot

Baobab / (root) directory statistics Rings Chart pie

 

baobab-entry-screen-debian-gnu-linux-disk-space-by-size-visualized-screenshot

baobab – Treemap Chart for directory usage sorted by size on disk 

!!! Note that before removing any files found as taking up too much space with baobab – make sure this files are not essential parts of a .deb package first, otherwise you might break up your system !!!

KDE (Plasma) QT library users could use Qdirstat instead of baobab 

qdirstat-on-gnu-linur checking what is the disk space bottleneck qdirstat KDE


6. Use ncdu or duper perl script tool to generate directory disk usage in ASCII chart bar

ncdu and duper are basicly the same except one is using ncurses and is interactive in a very simplistic interface with midnight commander.
 

# apt install –yes ncdu
# ncdu /root


ncdu-gnu-linux-debian-screenshot

 

# apt-get install –yes durep
# durep -td 1 /usr

[ /usr    14.4G (0 files, 11 dirs) ]
   6.6G [#############                 ]  45.54% lib/
   5.5G [###########                   ]  38.23% share/
   1.1G [##                            ]   7.94% bin/
 552.0M [#                             ]   3.74% local/
 269.2M [                              ]   1.83% games/
 210.4M [                              ]   1.43% src/
  88.9M [                              ]   0.60% libexec/
  51.3M [                              ]   0.35% sbin/
  41.2M [                              ]   0.28% include/
   8.3M [                              ]   0.06% lib32/
 193.8K [                              ]   0.00% lib64/

 

 

Conclusion


In this article, I've shortly explained the few approach you can take to handle low disk space preventing you to update a regular security updates on Linux.
The easiest one is to clone your drive to a bigger (larger) sized SATA HDD or SDD Drive or using a free space left on a hard drive to exnted the current filling up the root partition. 

Further, I looked through the common reasons for endind with a disk being low spaced and a quick work around to free disk space through listing and purging larges sized package, this is made differently in different Linux distributions, because different Linux has different package managers. As I'm primary using Debian, I explained thoroughfully on how this is achieved with apt-get / dpkg-query / dpkg / aptitude and the little known debian-goodies .deb package manager helper pack. For GUI Desktop users there is baobab / qdirstat. ASCII lovers could enjoy durep and ncdu.

That's all folks hope you enjoyed and learned something new. If you know of other cool tools or things this article is missing please share.

Check when Windows Active Directory user expires and set user password expire to Never


January 9th, 2020

micorosoft-windows-10-logo-net-user-command-check-expiry-dates

If you're working for a company that is following high security / PCI Security Standards and you're using m$ Windows OS that belongs to the domain it is useful to know when your user is set to expiry
to know how many days are left until you'll be forced to change your Windows AD password.
In this short article I'll explain how to check Windows AD last password set date / date expiry date and how you can list expiry dates for other users, finally will explain how to set your expiry date to Never
to get rid of annoying change password every 90 days.

 

1. Query domain Username for Password set / Password Expires set dates

To know this info you need to know the Password expiration date for Active Directory user account, to know it just open Command Line Prompt cmd.exe

And run command:
 

 

NET USER Your-User-Name /domain


net-user-domain-command-check-AD-user-expiry

Note that, many companies does only connect you to AD for security reason only on a VPN connect with something like Cisco AnyConnect Secure Mobility Client whatever VPN connect tool is used to encrypt the traffic between you and the corporate DMZ-ed network

Below is basic NET USER command usage args:

Net User Command Options
 

Item          Explanation

net user    Execute the net user command alone to show a very simple list of every user account, active or not, on the computer you're currently using.

username    This is the name of the user account, up to 20 characters long, that you want to make changes to, add, or remove. Using username with no other option will show detailed information about the user in the Command Prompt window.

password    Use the password option to modify an existing password or assign one when creating a new username. The minimum characters required can be viewed using the net accounts command. A maximum of 127 characters is allowed1.
*    You also have the option of using * in place of a password to force the entering of a password in the Command Prompt window after executing the net user command.

/add    Use the /add option to add a new username on the system.
options    See Additional Net User Command Options below for a complete list of available options to be used at this point when executing net user.

/domain    This switch forces net user to execute on the current domain controller instead of the local computer.

/delete    The /delete switch removes the specified username from the system.

/help    Use this switch to display detailed information about the net user command. Using this option is the same as using the net help command with net user: net help user.
/?    The standard help command switch also works with the net user command but only displays the basic command syntax. Executing net user without options is equal to using the /? switch.

 

 

2. Listing all Active Directory users last set date / never expires and expiration dates


If you have the respective Active Directory rights and you have the Remote Server Administration Tools for Windows (RSAT Tools), you are able to do also other interesting stuff,

 

such as

– using PowerShell to list all user last set dates, to do so use Open Power Shell and issue:
 

get-aduser -filter * -properties passwordlastset, passwordneverexpires |ft Name, passwordlastset, Passwordneverexpires


get-aduser-properties-passwordlastset-passwordneverexpires1

This should show you info as password last set date and whether password expiration is set for account.

– Using PS to get only the password expirations for all AD existing users is with:

 

Get-ADUser -filter {Enabled -eq $True -and PasswordNeverExpires -eq $False} –Properties "DisplayName", "msDS-UserPasswordExpiryTimeComputed" |
Select-Object -Property "Displayname",@{Name="ExpiryDate";Expression={[datetime]::FromFileTime($_."msDS-UserPasswordExpiryTimeComputed")}}


If you need the output data to get stored in CSV file delimitered format you can add to above PS commands
 

| export-csv YOUR-OUTPUT-FILE.CSV

 

3. Setting a user password to never Expiry

 

If the user was created with NET USER command by default it will have been created to have a password expiration. 
However if you need to create new users for yourself (assuming you have the rights), with passwords that never expire on lets say Windows Server 2016 – (if you don't care about security so much), use:
 

NET USER "Username" /Add /Active:Yes

WMIC USERACCOUNT WHERE "Name='Username' SET PasswordExpires=False

 

NET-USER-ADD_Active-yes-Microsoft-Windows-screenshot

NET-USER-set-password-policy-to-Never-expiry-MS-Windows

To view the general password policies, type following:
 

NET ACCOUNTS


NET-ACCOUNTS-view-default-Microsoft-Windows-password-policy