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Install Zabbix Agent client on CentOS 9 Stream Linux, Disable Selinux and Firewalld on CentOS9 to make zabbix-agentd send data to server

Thursday, April 14th, 2022

https://pc-freak.net/images/zabbix_agent_active_passive-zabbix-agent-centos-9-install-howto

Installing Zabbix is usually a trivial stuff, you either use the embedded distribution built packages if such are available this is for example defetch the right zabbix release repository  that configures the Zabbix official repo in the system, configure the Zabbix server or Proxy if such is used inside /etc/zabbix/zabbix_agentd.conf and start the client, i.e. I expected that it will be a simple and straight forward also on the freshly installed CentOS 9 Linux cause placing a zabbix-agent monitroing is a trivial stuff however installing came to error:

Key import failed (code 2). Failing package is: zabbix-agent-6.0.3-1.el8.x86_64

 

This is what I've done

1. Download and install zabbix-release-6.0-1.el8.noarch.rpm directly from zabbix

I've followed the official documentation from zabbix.com and ran:
 

[root@centos9 /root ]# rpm -Uvh https://repo.zabbix.com/zabbix/6.0/rhel/8/x86_64/zabbix-release-6.0-1.el8.noarch.rpm

…


2. Install  the zabbix-agent RPM package from the repositry

[root@centos9 rpm-gpg]# yum install zabbix-agent -y
Last metadata expiration check: 0:02:46 ago on Tue 12 Apr 2022 08:49:34 AM EDT.
Dependencies resolved.
=============================================
 Package                               Architecture                Version                              Repository                      Size
=============================================
Installing:
 zabbix-agent                          x86_64                      6.0.3-1.el8                          zabbix                         526 k
Installing dependencies:
 compat-openssl11                      x86_64                      1:1.1.1k-3.el9                       appstream                      1.5 M
 openldap-compat                       x86_64                      2.4.59-4.el9                         baseos                          14 k

Transaction Summary
==============================================
Install  3 PackagesTotal size: 2.0 M
Installed size: 6.1 M
Downloading Packages:
[SKIPPED] openldap-compat-2.4.59-4.el9.x86_64.rpm: Already downloaded
[SKIPPED] compat-openssl11-1.1.1k-3.el9.x86_64.rpm: Already downloaded
[SKIPPED] zabbix-agent-6.0.3-1.el8.x86_64.rpm: Already downloaded
Zabbix Official Repository – x86_64                                                                          1.6 MB/s | 1.7 kB     00:00
Importing GPG key 0xA14FE591:
 Userid     : "Zabbix LLC <packager@zabbix.com>"
 Fingerprint: A184 8F53 52D0 22B9 471D 83D0 082A B56B A14F E591
 From       : /etc/pki/rpm-gpg/RPM-GPG-KEY-ZABBIX-A14FE591
Key import failed (code 2). Failing package is: zabbix-agent-6.0.3-1.el8.x86_64
 GPG Keys are configured as: file:///etc/pki/rpm-gpg/RPM-GPG-KEY-ZABBIX-A14FE591
The downloaded packages were saved in cache until the next successful transaction.
You can remove cached packages by e
xecuting 'yum clean packages'.
Error: GPG check FAILED


3. Work around to skip GPG to install zabbix-agent 6 on CentOS 9

With Linux everything becomes more and more of a hack …
The logical thing to was to first,  check and it assure that the missing RPM GPG key is at place

[root@centos9 rpm-gpg]# ls -al  /etc/pki/rpm-gpg/RPM-GPG-KEY-ZABBIX-A14FE591
-rw-r–r– 1 root root 1719 Feb 11 16:29 /etc/pki/rpm-gpg/RPM-GPG-KEY-ZABBIX-A14FE591

Strangely the key was in place.

Hence to have the key loaded I've tried to import the gpg key manually with gpg command:

[root@centos9 rpm-gpg]# gpg –import /etc/pki/rpm-gpg/RPM-GPG-KEY-ZABBIX-A14FE591


And attempted install again zabbix-agent once again:
 

[root@centos9 rpm-gpg]# yum install zabbix-agent -y
Last metadata expiration check: 0:02:46 ago on Tue 12 Apr 2022 08:49:34 AM EDT.
Dependencies resolved.
==============================================
 Package                               Architecture                Version                              Repository                      Size
==============================================
Installing:
 zabbix-agent                          x86_64                      6.0.3-1.el8                          zabbix                         526 k
Installing dependencies:
 compat-openssl11                      x86_64                      1:1.1.1k-3.el9                       appstream                      1.5 M
 openldap-compat                       x86_64                      2.4.59-4.el9                         baseos                          14 k

Transaction Summary
==============================================
Install  3 Packages

Total size: 2.0 M
Installed size: 6.1 M
Downloading Packages:
[SKIPPED] openldap-compat-2.4.59-4.el9.x86_64.rpm: Already downloaded
[SKIPPED] compat-openssl11-1.1.1k-3.el9.x86_64.rpm: Already downloaded
[SKIPPED] zabbix-agent-6.0.3-1.el8.x86_64.rpm: Already downloaded
Zabbix Official Repository – x86_64                                                                          1.6 MB/s | 1.7 kB     00:00
Importing GPG key 0xA14FE591:
 Userid     : "Zabbix LLC <packager@zabbix.com>"
 Fingerprint: A184 8F53 52D0 22B9 471D 83D0 082A B56B A14F E591
 From       : /etc/pki/rpm-gpg/RPM-GPG-KEY-ZABBIX-A14FE591
Key import failed (code 2). Failing package is: zabbix-agent-6.0.3-1.el8.x86_64
 GPG Keys are configured as: file:///etc/pki/rpm-gpg/RPM-GPG-KEY-ZABBIX-A14FE591
The downloaded packages were saved in cache until the next successful transaction.
You can remove cached packages by executing 'yum clean packages'.
Error: GPG check FAILED


Unfortunately that was not a go, so totally pissed off I've disabled the gpgcheck for packages completely as a very raw bad and unrecommended work-around to eventually install the zabbix-agentd like that.

Usually the RPM gpg key failures check on RPM packages could be could be workaround with in dnf, so I've tried that one without success.

[root@centos9 rpm-gpg]# dnf update –nogpgcheck
Total                                                                                                        181 kB/s | 526 kB     00:02
Zabbix Official Repository – x86_64                                                                          1.6 MB/s | 1.7 kB     00:00
Importing GPG key 0xA14FE591:
 Userid     : "Zabbix LLC <packager@zabbix.com>"
 Fingerprint: A184 8F53 52D0 22B9 471D 83D0 082A B56B A14F E591
 From       : /etc/pki/rpm-gpg/RPM-GPG-KEY-ZABBIX-A14FE591
Is this ok [y/N]: y
Key import failed (code 2). Failing package is: zabbix-agent-6.0.3-1.el8.x86_64
 GPG Keys are configured as: file:///etc/pki/rpm-gpg/RPM-GPG-KEY-ZABBIX-A14FE591
The downloaded packages were saved in cache until the next successful transaction.
You can remove cached packages by executing 'dnf clean packages'.
Error: GPG check FAILED

Further tried to use the –nogpgpcheck 
which according to its man page:


–nogpgpcheck 
Skip checking GPG signatures on packages (if RPM policy allows).


In yum the nogpgcheck option according to its man yum does exactly the same thing


[root@centos9 rpm-gpg]# yum install zabbix-agent –nogpgcheck -y
 

Dependencies resolved.
===============================================
 Package                             Architecture                  Version                               Repository                     Size
===============================================
Installing:
 zabbix-agent                        x86_64                        6.0.3-1.el8                           zabbix                        526 k

Transaction Summary
===============================================

Total size: 526 k
Installed size: 2.3 M
Is this ok [y/N]: y
Downloading Packages:
…
Running transaction check
Transaction check succeeded.
Running transaction test
Transaction test succeeded.
Running transaction
  Preparing        :                                                                                                                     1/1
  Running scriptlet: zabbix-agent-6.0.3-1.el8.x86_64                                                                                     1/2
  Reinstalling     : zabbix-agent-6.0.3-1.el8.x86_64                                                                                     1/2
  Running scriptlet: zabbix-agent-6.0.3-1.el8.x86_64                                                                                     1/2
  Running scriptlet: zabbix-agent-6.0.3-1.el8.x86_64                                                                                     2/2
  Cleanup          : zabbix-agent-6.0.3-1.el8.x86_64                                                                                     2/2
  Running scriptlet: zabbix-agent-6.0.3-1.el8.x86_64                                                                                     2/2
  Verifying        : zabbix-agent-6.0.3-1.el8.x86_64                                                                                     1/2
  Verifying        : zabbix-agent-6.0.3-1.el8.x86_64                                                                                     2/2

Installed:
  zabbix-agent-6.0.3-1.el8.x86_64

Complete!
[root@centos9 ~]#

Voila! zabbix-agentd on CentOS 9 Install succeeded!

Yes I know disabling a GPG check is not really secure and seems to be an ugly solution but since I'm cut of time in the moment and it is just for experimental install of zabbix-agent on CentOS
plus we already trusted the zabbix package repository anyways, I guess it doesn't much matter.

4. Configure Zabbix-agent on the machine

Once you choose how the zabbix-agent should sent the data to the zabbix-server (e.g. Active or Passive) mode the The minimum set of configuration you should
have at place should be something like mine:

[root@centos9 ~]# grep -v '\#' /etc/zabbix/zabbix_agentd.conf | sed /^$/d
PidFile=/var/run/zabbix/zabbix_agentd.pid
LogFile=/var/log/zabbix/zabbix_agentd.log
LogFileSize=0
Server=192.168.1.70,127.0.0.1
ServerActive=192.168.1.70,127.0.0.1
Hostname=centos9
Include=/etc/zabbix/zabbix_agentd.d/*.conf

5. Start and Enable zabbix-agent client

To have it up and running

[root@centos9 ~]# systemct start zabbix-agent
[root@centos9 ~]# systemctl enable zabbix-agent

6. Disable SELinux to prevent it interfere with zabbix-agentd 

Other amazement was that even though I've now had configured Active check and a Server and correct configuration the Zabbix-Server could not reach the zabbix-agent for some weird reason.
I thought that it might be selinux and checked it and seems by default in the fresh installed CentOS 9 Linux selinux is already automatically set to enabled.

After stopping it i made sure, SeLinux would block for security reasons client connectivity to the zabbix-server until you either allow zabbix exception in SeLinux or until completely disable it.
 

[root@centos9 ~]# sestatus

SELinux status:                 enabled
SELinuxfs mount:                /sys/fs/selinux
SELinux root directory:         /etc/selinux
Loaded policy name:             targeted
Current mode:                   enforcing
Mode from config file:          enforcing
Policy MLS status:              enabled
Policy deny_unknown status:     allowed
Memory protection checking:     actual (secure)
Max kernel policy version:      31

To temporarily change the mode from its default targeted to permissive mode 

[root@centos9 ~]# setenforce 0

[root@centos9 ~]# sestatus

SELinux status:                 enabled
SELinuxfs mount:                /sys/fs/selinux
SELinux root directory:         /etc/selinux
Loaded policy name:             targeted
Current mode:                   permissive
Mode from config file:          permissive
Policy MLS status:              enabled
Policy deny_unknown status:     allowed
Memory protection checking:     actual (secure)
Max kernel policy version:      31


That would work for current session but won't take affect on next reboot, thus it is much better to disable selinux on next boot:

[root@centos9 ~]# cat /etc/selinux/config
# This file controls the state of SELinux on the system.
# SELINUX= can take one of these three values:
#     enforcing – SELinux security policy is enforced.
#     permissive – SELinux prints warnings instead of enforcing.
#     disabled – No SELinux policy is loaded.
SELINUX=permissive
# SELINUXTYPE= can take one of these three values:
#     targeted – Targeted processes are protected,
#     minimum – Modification of targeted policy. Only selected processes are protected. 
#     mls – Multi Level Security protection.
SELINUXTYPE=targeted

 

To disable selinux change:

SELINUXTYPE=disabled

[root@centos9 ~]# grep -v \# /etc/selinux/config

SELINUX=disabled
SELINUXTYPE=targeted


To make the OS disable selinux and test it is disabled you will have to reboot 

[root@centos9 ~]# reboot


Check its status again, it should be:

[root@centos9 ~]# sestatus
SELinux status:                 disabled


7. Enable zabbix-agent through firewall or disable firewalld service completely

By default CentOS 9 has the firewalld also enabled and either you have to enable zabbix to communicate to the remote server host.

To enable access for from and to zabbix-agentd in both Active / Passive mode:

#firewall settings:
[root@centos9 rpm-gpg]# firewall-cmd –permanent –add-port=10050/tcp
[root@centos9 rpm-gpg]# firewall-cmd –permanent –add-port=10051/tcp
[root@centos9 rpm-gpg]# firewall-cmd –reload
[root@centos9 rpm-gpg]# systemctl restart firewalld
[root@centos9 rpm-gpg]# systemctl restart zabbix-agent


If the machine is in a local DMZ-ed network with tightly configured firewall router in front of it, you could completely disable firewalld.

[root@centos9 rpm-gpg]# systemctl stop firewalld
[root@centos9 rpm-gpg]# systemctl disable firewalld
Removed /etc/systemd/system/multi-user.target.wants/firewalld.service.
Removed /etc/systemd/system/dbus-org.fedoraproject.FirewallD1.service.

 

Next login to Zabbix-server web interface with administrator and from Configuration -> Hosts -> Create the centos9 hostname and add it a template of choice. The data from the added machine should shortly appear after another zabbix restart:

[root@centos9 rpm-gpg]#  systemctl restart zabbix-agentd


8. Tracking other oddities with the zabbix-agent through log

If anyways still zabbix have issues connectin to remote node, increase the debug log level section
 

[root@centos9 rpm-gpg]# vim /etc/zabbix/zabbix_agentd.conf
DebugLevel 5

### Option: DebugLevel
#       Specifies debug level:
#       0 – basic information about starting and stopping of Zabbix processes
#       1 – critical information
#       2 – error information
#       3 – warnings
#       4 – for debugging (produces lots of information)
#       5 – extended debugging (produces even more information)
#
# Mandatory: no
# Range: 0-5
# Default:
# DebugLevel=3

[root@centos9 rpm-gpg]# systemctl restart zabbix-agent

Keep in mind that debugging will be too verbose, so once you make the machine being seen in zabbix, don't forget to comment out the line and restart agent to turn it off.

9. Testing zabbix-agent, How to send an alert to specific item key

Usually when writting userparameter scripts, data collected from scripts is being sent to zabbix serveria via Item keys.
Thus one way to check the zabbix-agent -> zabbix server data send works fine is to send some simultaneous data via a key
Once zabbix-agent is configured on the machine 

In this case we will use something like ApplicationSupport-Item as an item.
 

[root@centos9 rpm-gpg]# /usr/bin/zabbix_sender -c "/etc/zabbix/zabbix_agentd.conf" -k "ApplicationSupport-Item" -o "here is the message"

Assuming you have created the newly prepared zabbix-agent host into Zabbix Server, you should be shortly able to see the data come in Latest data.

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Posted in CentOS, Linux, Monitoring, Zabbix | No Comments »

Monitoring chronyd time service is synchronized, get additional time server values with Zabbix userparameter script

Monday, March 21st, 2022

monitoring-chronyc-time-server-synchronization-zabbix-logo

If you''re running a server infrastructure and your main monitoring system is Zabbix. Then a vital check you might want to setup is to monitor the server time synchronization to a central server. In newer Linux OS-es ntpd time server is started to be used lesser and many modern Linux distributions used in the corporate realm are starting to recommend using chrony as a time synchronization client / server.

In this article, I'll show you how you can quickly setup monitoring of chronyd process and monitoring whether the time is successfully synchronizing with remote Chronyd time server. This will be done with a tiny one liner shell script setup as userparameter It is relatively easy then to setup an Action Alert


1. Create userparameter script to send parsed chronyd time synchronization to Zabbix Server

chronyc tracking provides plenty of useful data which can give many details about info such as offset, skew, root delay, stratum, update interval.

[root@server: ~]# chronyc tracking
Reference ID    : 0A32EF0B (fkf-intp01.intcs.meshcore.net)
Stratum         : 3
Ref time (UTC)  : Fri Mar 18 12:42:31 2022
System time     : 0.000032544 seconds fast of NTP time
Last offset     : +0.000031102 seconds
RMS offset      : 0.000039914 seconds
Frequency       : 3.037 ppm slow
Residual freq   : +0.000 ppm
Skew            : 0.023 ppm
Root delay      : 0.017352410 seconds
Root dispersion : 0.004285847 seconds
Update interval : 1041.6 seconds
Leap status     : Normal

[root@server zabbix_agentd.d]# cat userparameter_chrony.conf 
UserParameter=chrony.json,chronyc -c tracking | sed -e s/'^'/'{"chrony":[“‘/g -e s/’$’/'”]}'/g -e s/','/'","'/g
[root@server zabbix_agentd.d]#

The -c option passed to chronyc is printing the chronyc tracking command ouput data in comma-separated values ( CSV ) format.

2. Create Necessery Item key to get chronyd processes and catch the userparameter data

 

  • First lets create a an Item key to calculate the chronyd daemon proc.num
    proc.num – simply returns the number of processes in the process list just like a simple
    pgrep servicename command does.


monitroing-chronyc_zabbix_item_report_to-zabbix

Second lets create the Item for the userparameter script, the chrony.json key should be the same as the key given in the userparameter script.

obtain-chronyc-statistic-variables-from-remote-chronyd-to-zabbix-windows

Create Chrony Zabbix Triggers 
 

Expression 

{server-host:proc.num[chronyd].last()}<1


will be triggered if the process of chronyd on the server is less than 1

 

chronyc_monitoring_process-is-not-running-screenshot

Next configure

{server-host:chrony[Leap status].iregexp[Not synchronised) ]=1


to trigger Alert Chronyd is Not synchronized if the Expression check occurs.

chronyd-is-not-synchronized-trigger-iregexp

Reload the zabbix-agent on the server
 

To make zabbix-agent locally installed on the machine read the userparameter into memory  (in my case this is zabbix-agent-4.0.28-1.el8.x86_64) installed on Redhat 8.3 (Ootpa), you have to restart it.

[root@server: ~]# systemctl restart zabbix-agent
[root@server: ~]# systemctl status zabbix-agent

● zabbix-agent.service – Zabbix Agent
   Loaded: loaded (/usr/lib/systemd/system/zabbix-agent.service; enabled; vendor preset: disabled)
   Active: active (running) since Thu 2021-12-16 16:41:02 CET; 3 months 0 days ago
 Main PID: 862165 (zabbix_agentd)
    Tasks: 6 (limit: 23662)
   Memory: 20.6M
   CGroup: /system.slice/zabbix-agent.service
           ├─862165 /usr/sbin/zabbix_agentd -c /etc/zabbix/zabbix_agentd.conf
           ├─862166 /usr/sbin/zabbix_agentd: collector [idle 1 sec]
           ├─862167 /usr/sbin/zabbix_agentd: listener #1 [waiting for connection]
           ├─862168 /usr/sbin/zabbix_agentd: listener #2 [waiting for connection]
           ├─862169 /usr/sbin/zabbix_agentd: listener #3 [waiting for connection]
           └─862170 /usr/sbin/zabbix_agentd: active checks #1 [idle 1 sec]

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


In a short while you should be seeing in the chrony.json key History data fed by the userparameter Script.

In Zabbix Latest data, you will see plenty of interesting time synchronization data get reported such as Skew, Stratum, Root Delay, Update Interval, Frequency etc.

chronyd-zabbix-reported-time-synchronization-offset-leap-residual-freq-root-delay-screenshot

To have an email Alerting further, go and setup a new Zabbix Action based on the Trigger with your likings and you're done. 
The tracked machine will be in zabbix to make sure your OS clock is not afar from the time server. Repeat the same steps if you need to track chronyd is up running and synchronized on few machines, or if you have to make it for dozens setup a Zabbix template.

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Posted in Linux, Zabbix | No Comments »

Monitor service log is continously growing with Zabbix on Windows with batch userparameter script and trigger Alert if log is unchanged

Thursday, March 17th, 2022

monitor-if-log-file-is-growing-with-zabbix-zabbix-userparameter-script-howto

Recently we had an inteteresting Monitoring work task to achieve. We have an Application that is constantly simulating encrypted connections traffic to a remote side machine and sending specific data on TCP/IP ports.
Communiucation between App Server A -> App Server B should be continous and if all is working as expected App Server A messages output are logged in the Application log file on the machine which by the way Runs
Windows Server 2020.

Sometimes due to Network issues this constant reconnections from the Application S. A to the remote checked machine TCP/IP ports gets interrupted due to LAN issues or a burned Network Switch equipment, misconfiguration on the network due to some Network admin making stoopid stuff etc..

Thus it was important to Monitor somehow whether the log is growing or not and feed the output of whether Application log file is growing or it stuck to a Central Zabbix Server. 
To be able to better understand the task, lets divide the desired outcome in few parts on required:

1. Find The latest file inside a folder C:\Path-to-Service\Monitoring\Log\
2. Open the and check it is current logged records and log the time
3. Re-open file in a short while and check whether in few seconds new records are written
4. Report the status out to Zabbix
5. Make Zabbix Item / Trigger / Action in case if monitored file is not growing

In below article I'll briefly explain how Monitoring a Log on a Machine for growing was implemented using a pure good old WIN .BAT (.batch) script and Zabbix Userparameter key

 

1. Enable userparameter script for Local Zabbix-Agent on the Windows 10 Server Host


Edit Zabbix config file usually on Windows Zabbix installs file is named:

[ zabbix_agentd.win ]


Uncomment the following lines to enable userparameter support for zabbix-agentd:

 

# Include=c:\zabbix\zabbix_agentd.userparams.conf

Include=c:\zabbix\zabbix_agentd.conf.d\

# Include=c:\zabbix\zabbix_agentd.conf.d\*.conf


2. Create folders for userparameter script and for the userparameter.conf

Before creating userparameter you can to create the folder and grant permissions

Folder name under C:\Zabbix -> zabbix_agentd.conf.d

If you don't want to use Windows Explorer) but do it via cmd line:

C:\Users\LOGUser> mkdir \Zabbix\zabbix_agentd.conf\
C:\User\LOGUser> mkdir \Zabbix\zabbix_scripts\


3. Create Userparameter with some name file ( Userparameter-Monitor-Grow.conf )

In the directory C:\Zabbix\zabbix_agentd.conf.d you should create a config file like:
Userparameter-Monitor-Grow.conf and in it you should have a standard userparameter key and script so file content is:

UserParameter=service.check,C:\Zabbix\zabbix_scripts\GROW_LOG_MONITOR-USERPARAMETER.BAT


4. Create the Batch script that will read the latest file in the service log folder and will periodically check and report to zabbix that file is changing

notepad C:\Zabbix\zabbix_scripts\GROW_LOG_MONITOR-USERPARAMETER.BAT

REM "SCRIPT MONITOR IF FILE IS GROWING OR NOT"
@echo off

set work_dir=C:\Path-to-Service\Monitoring\Log\

set client=client Name

set YYYYMMDD=%DATE:~10,4%%DATE:~4,2%%DATE:~7,2%

set name=csv%YYYYMMDD%.csv

set mytime=%TIME:~0,8%

for %%I in (..) do set CurrDirName=%%~nxI

 

setlocal EnableDelayedExpansion

set "line1=findstr /R /N "^^" %work_dir%\output.csv | find /C ":""


for /f %%a in ('!line1!') do set number1=%%a

set "line2=findstr /R /N "^^" %work_dir%\%name% | find /C ":""


for /f %%a in ('!line2!') do set number2=%%a

 

IF  %number1% == %number2% (

echo %YYYYMMDD% %mytime% MAJOR the log is not incrementing for %client%

echo %YYYYMMDD% %mytime% MAJOR the log is not incrementing for %client% >> monitor-grow_err.log

) ELSE (

echo %YYYYMMDD% %mytime% NORMAL the log is incrementing for %client%

SETLOCAL DisableDelayedExpansion

del %work_dir%\output.csv

FOR /F "usebackq delims=" %%a in (`"findstr /n ^^ %work_dir%\%name%"`) do (

    set "var=%%a"

    SETLOCAL EnableDelayedExpansion

    set "var=!var:*:=!"

    echo(!var! >> %work_dir%\output.csv

    ENDLOCAL

)

)
 

 

To download GROW_LOG_MONITOR-USERPARAMETER.BAT click here.
The script needs to have configured the path to directory containing multiple logs produced by the Monitored Application.
As prior said it will, list the latest created file based on DATE timestamp in the folder will output a simple messages:

If the log file is being fed with data the script will output to output.csv messages continuously, either:

%%mytime%% NORMAL the log is incrementing for %%client%%

Or if the Monitored application log is not writting anything for a period it will start writting messages

%%mytime%%mytime MAJOR the log is not incrementing for %client%

The messages will also be sent in Zabbix.

Before saving the script make sure you modify the Full Path location to the Monitored file for growing, i.e.:

set work_dir=C:\Path-to-Service\Monitoring\Log\


5. Create The Zabbix Item

Set whatever service.check name you would like and a check interval to fetch the info from the userparameter (if you're dealing with very large log files produced by Monitored log of application, then 10 minutes might be too frequent, in most cases 10 minutes should be fine)
monitor-if-log-grows-windows-zabbix-item-service-check-screenshot
 

6. Create Zabbix Trigger


You will need a Trigger something similar to below:

Now considering that zabbix server receives correctly data from the client and the monitored log is growing you should in Zabbix:

%%mytime%% NORMAL the log is incrementing for %%client%%


7. Lastly create an Action to send Email Alert if log is not growing

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Zabbix rkhunter monitoring check if rootkits trojans and viruses or suspicious OS activities are detected

Wednesday, December 8th, 2021

monitor-rkhunter-with-zabbix-zabbix-rkhunter-check-logo

If you're using rkhunter to monitor for malicious activities, a binary changes, rootkits, viruses, malware, suspicious stuff and other famous security breach possible or actual issues, perhaps you have configured your machines to report to some Email.
But what if you want to have a scheduled rkhunter running on the machine and you don't want to count too much on email alerting (especially because email alerting) makes possible for emails to be tracked by sysadmin pretty late?

We have been in those situation and in this case me and my dear colleague Georgi Stoyanov developed a small rkhunter Zabbix userparameter check to track and Alert if any traces of "Warning"''s are mateched in the traditional rkhunter log file /var/log/rkhunter/rkhunter.log

To set it up and use it is pretty use you will need to have a recent version of zabbix-agent installed on the machine and connected to a Zabbix server, in my case this is:

[root@centos ~]# rpm -qa |grep -i zabbix-agent
zabbix-agent-4.0.7-1.el7.x86_64

 placed inside /etc/zabbix/zabbix_agentd.d/userparameter_rkhunter_warning_check.conf

[root@centos /etc/zabbix/zabbix_agentd.d ]# cat userparameter_rkhunter_warning_check.conf
# userparameter script to check if any Warning is inside /var/log/rkhunter/rkhunter.log and if found to trigger Zabbix alert
UserParameter=rkhunter.warning, (TODAY=$(date |awk '{ print $1" "$2" "$3 }'); if [ $(cat /var/log/rkhunter/rkhunter.log | awk “/$TODAY/,EOF” | /bin/grep -i ‘\[ Warning \]’ | /usr/bin/wc -l) != ‘0’ ]; then echo 1; else echo 0; fi)
UserParameter=rkhunter.suspected,(/bin/grep -i 'Suspect files: ' /var/log/rkhunter/rkhunter.log|tail -n 1| awk '{ print $4 }')
UserParameter=rkhunter.rootkits,(/bin/grep -i 'Possible rootkits: ' /var/log/rkhunter/rkhunter.log|tail -n 1| awk '{ print $4 }')


2. Prepare Rkhunter Template, Triggers and Items


In Zabbix Server that you access from web control interface, you will have to prepare a new template called lets say Rkhunter with the necessery Triggers and Items


2.1 Create Rkhunter Items
 

On Zabbix Server side, uou will have to configure 3 Items for the 3 configured userparameter above script keys, like so:

rkhunter-items-zabbix-screenshot.png

  • rkhunter.suspected Item configuration


rkhunter-suspected-files

  • rkhunter.warning Zabbix Item config

rkhunter-warning-found-check-zabbix

  • rkhunter.rootkits Zabbix Item config

     

     

    rkhunter-zabbix-possible-rootkits-item1

    2.2 Create Triggers
     

You need to have an overall of 3 triggers like in below shot:

zabbix-rkhunter-all-triggers-screenshot
 

  • rkhunter.rootkits Trigger config

rkhunter-rootkits-trigger-zabbix1

  • rkhunter.suspected Trigger cfg

rkhunter-suspected-trigger-zabbix1

  • rkhunter warning Trigger cfg

rkhunter-warning-trigger1

3. Reload zabbix-agent and test the keys


It is necessery to reload zabbix agent for the new userparameter to start to be sent to remote zabbix server (through a proxy if you have one configured).

[root@centos ~]# systemctl restart zabbix-agent
…


To make the zabbix-agent send the keys to the server you can use zabbix_sender to have the test tool you will have to have installed (zabbix-sender) on the server.

To trigger a manualTest if you happen to have some problems with the key which shouldn''t be the case you can sent a value to the respectve key with below command:

[root@centos ~ ]# zabbix_sender -vv -c "/etc/zabbix/zabbix_agentd.conf" -k "khunter.warning" -o "1"


Check on Zabbix Server the sent value is received, for any oddities as usual check what is inside  /var/log/zabbix/zabbix_agentd.log for any errors or warnings.

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How to set up dsmc client Tivoli ( TSM ) release version and process check monitoring with Zabbix

Thursday, December 17th, 2020

zabbix-monitor-dsmc-client-monitor-ibm-tsm-with-zabbix-howto

As a part of Monitoring IBM Spectrum (the new name of IBM TSM) if you don't have the money to buy something like HP Open View monitoring or other kind of paid monitoring system but you use Zabbix open source solution to monitor your Linux server infrastructure and you use Zabbix as a main Services and Servers monitoring platform you will want to monitor at least whether the running Tivoli dsmc backup clients run fine on each of the server (e.g. the dsmc client) runs normally as a backup solution with its common /usr/bin/dsmc process service that connects towards remote IBM TSM server where the actual Data storage is kept.

It might be a kind of weird monitoring to setup to have the tsm version frequently reported to a Zabbix server on a first glimpse, but in reality this is quite useful especially if you want to have a better overview of your multiple servers environment IBM (Spectrum Protect) Storage manager backup solution actual release.
 
So the goal is to have reported dsmc interactive storage manager version as reported from
 

[root@server ~]# dsmc

IBM Spectrum Protect
Command Line Backup-Archive Client Interface
  Client Version 8, Release 1, Level 11.0
  Client date/time: 12/17/2020 15:59:32
(c) Copyright by IBM Corporation and other(s) 1990, 2020. All Rights Reserved.

Node Name: Sub-Hostname.FQDN.COM
Session established with server TSM_SERVER: AIX
  Server Version 8, Release 1, Level 10.000
  Server date/time: 12/17/2020 15:59:34  Last access: 12/17/2020 13:28:01

 

into zabbix and set reports in case if your sysadmins have changed version of a IBM TSM to a newer version. Thus for non sysadmins and less technical persons as Service Delivery Managers (SDMs) it is much easier to track changes of multiple servers Tivoli version to a newer one.

Enough talk let me next show you how to setup the required with a small UserParameter one liner bash shell script.
 

1. Create TSM Userparameter script


With Userparameter key and content as below:

[root@server ~]# vim /etc/zabbix/zabbix_agentd.d/userparameter_TSM.conf

 

UserParameter=dsmc.version,cat /var/tsm/sched.log | grep Clie | tail -n 1 | awk '{print $7 " " $8 " " $9 " " $10 " " $11 " " $12 " " $13}'


The script output of TivSM version will be reported as so:

[root@server ~]# cat /var/tsm/sched.log | grep Clie | tail -n 1 | awk '{print $7 " " $8 " " $9 " " $10 " " $11 " " $12 " " $13}'
Client Version 8, Release 1, Level 11.0


 

If you want to get only a major version report from dsmc:

UserParameter=dsmc.version,cat /var/tsm/sched.log | grep Clie | tail -n 1 | awk '{print $7 " " $8 " " $9}'


The output as a major version you will get is

[root@server ~]# cat /var/tsm/sched.log | grep Clie | tail -n 1 | awk '{print $7 " " $8 " " $9}'
Client Version 8,

 

2. Restart the zabbix agent to load userparam script

To load above configured Userparameter script we need to restart zabbix-agent client

[root@server ~]# systemctl restart zabbix-agent

[root@server ~]#  systemctl status zabbix-agent
● zabbix-agent.service – Zabbix Agent
   Loaded: loaded (/usr/lib/systemd/system/zabbix-agent.service; enabled; vendor preset: disabled)
   Active: active (running) since Wed 2020-07-22 16:17:17 CEST; 4 months 26 days ago
 Main PID: 7817 (zabbix_agentd)
   CGroup: /system.slice/zabbix-agent.service
           ├─7817 /usr/sbin/zabbix_agentd -c /etc/zabbix/zabbix_agentd.conf
           ├─7818 /usr/sbin/zabbix_agentd: collector [idle 1 sec]
           ├─7819 /usr/sbin/zabbix_agentd: listener #1 [waiting for connection]
           ├─7820 /usr/sbin/zabbix_agentd: listener #2 [waiting for connection]
           ├─7821 /usr/sbin/zabbix_agentd: listener #3 [waiting for connection]
           └─7822 /usr/sbin/zabbix_agentd: active checks #1 [idle 1 sec]

 

3. Create template for TSM Service check and TSM Version


You will need to create 1 Trigger and 2 Items for the Service check and for TSM version reporting

tsm-service-version-screenshot-zabbix
As you see necessery names / keys to create are:

Name / Key: TSM – Service State proc.num{dsmcad}

Name / key: TSM version dmsc.version

 

3.1 Create the trigger


Now lets create the trigger that will report the Service State

tsm-service-state-zabbix-screenshot

 

Linux TSM:proc.num[dsmcad].last()}=0

 

3.2 Create the Items


zabbix-dsmc-proc-num-item-setting-screenshot-linux

 

Name: dsmcad
Key: proc.num{dsmcad}

 

tsm-version-item-zabbix-screenshot
 

Update interval: 1d
History Storage period: 90d
Applications: TSM


3.3 Create Zabbix Action

As usual if you want to receive some Email Alerting or lets say send SMS in case of Trigger is matched create the necessery Action with
instructions on how to solve the problem if there is a Standard Operation Procedure ( SOP ) as often called in the corporate world for that.

That's all folks ! 🙂

 

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How to calculate connections from IP address with shell script and log to Zabbix graphic

Thursday, March 11th, 2021

We had to test the number of connections incoming IP sorted by its TCP / IP connection state.

For example:

TIME_WAIT, ESTABLISHED, LISTEN etc.


The reason behind is sometimes the IP address '192.168.0.1' does create more than 200 connections, a Cisco firewall gets triggered and the connection for that IP is filtered out. To be able to know in advance that this problem is upcoming. a Small userparameter script is set on the Linux servers, that does print out all connections from IP by its STATES sorted out.

 

The script is calc_total_ip_match_zabbix.sh is below:

#!/bin/bash
#  check ESTIMATED / FIN_WAIT etc. netstat output for IPs and calculate total
# UserParameter=count.connections,(/usr/local/bin/calc_total_ip_match_zabbix.sh)
CHECK_IP='192.168.0.1';
f=0; 

 

for i in $(netstat -nat | grep "$CHECK_IP" | awk '{print $6}' | sort | uniq -c | sort -n); do

echo -n "$i ";
f=$((f+i));
done;
echo
echo "Total: $f"

 

root@pcfreak:/bashscripts# ./calc_total_ip_match_zabbix.sh 
1 TIME_WAIT 2 ESTABLISHED 3 LISTEN 

Total: 6

 

root@pcfreak:/bashscripts# ./calc_total_ip_match_zabbix.sh 
2 ESTABLISHED 3 LISTEN 
Total: 5


images/zabbix-webgui-connection-check1

To make process with Zabbix it is necessery to have an Item created and a Depedent Item.

 

webguiconnection-check1

webguiconnection-check1
 

webgui-connection-check2-item

images/webguiconnection-check1

Finally create a trigger to trigger alarm if you have more than or eqaul to 100 Total overall connections.


images/zabbix-webgui-connection-check-trigger

The Zabbix userparameter script should be as this:

[root@host: ~]# cat /etc/zabbix/zabbix_agentd.d/userparameter_webgui_conn.conf
UserParameter=count.connections,(/usr/local/bin/webgui_conn_track.sh)

 

Some collleagues suggested more efficient shell script solution for suming the overall number of connections, below is less time consuming version of script, that can be used for the calculation.
 

#!/bin/bash -x
# show FIN_WAIT2 / ESTIMATED etc. and calcuate total
count=$(netstat -n | grep "192.168.0.1" | awk ' { print $6 } ' | sort -n | uniq -c | sort -nr)
total=$((${count// /+}))
echo "$count"
echo "Total:" "$total"

      2 ESTABLISHED
      1 TIME_WAIT
Total: 3

 


Below is the graph built with Zabbix showing all the fluctuations from connections from monitored IP. ebgui-check_ip_graph

 

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How to calculate connections from IP address with shell script and log to Zabbix graphic

Thursday, March 11th, 2021

We had to test the number of connections incoming IP sorted by its TCP / IP connection state.

For example:

TIME_WAIT, ESTABLISHED, LISTEN etc.


The reason behind is sometimes the IP address '192.168.0.1' does create more than 200 connections, a Cisco firewall gets triggered and the connection for that IP is filtered out. To be able to know in advance that this problem is upcoming. a Small userparameter script is set on the Linux servers, that does print out all connections from IP by its STATES sorted out.

 

The script is calc_total_ip_match_zabbix.sh is below:

#!/bin/bash
#  check ESTIMATED / FIN_WAIT etc. netstat output for IPs and calculate total
# UserParameter=count.connections,(/usr/local/bin/calc_total_ip_match_zabbix.sh)
CHECK_IP='192.168.0.1';
f=0; 

 

for i in $(netstat -nat | grep "$CHECK_IP" | awk '{print $6}' | sort | uniq -c | sort -n); do

echo -n "$i ";
f=$((f+i));
done;
echo
echo "Total: $f"

 

root@pcfreak:/bashscripts# ./calc_total_ip_match_zabbix.sh 
1 TIME_WAIT 2 ESTABLISHED 3 LISTEN 

Total: 6

 

root@pcfreak:/bashscripts# ./calc_total_ip_match_zabbix.sh 
2 ESTABLISHED 3 LISTEN 
Total: 5


To make process with Zabbix it is necessery to have an Item created and a Depedent Item.

images/zabbix-webgui-connection-check1

 

 

 

 

webguiconnection-check1

webguiconnection-check1
 

webgui-connection-check2-item

images/webguiconnection-check1

Finally create a trigger to trigger alarm if you have more than or eqaul to 100 Total overall connections.


images/zabbix-webgui-connection-check-trigger

The Zabbix userparameter script should be as this:
cat /etc/zabbix/zabbix_agentd.d/userparameter_webgui_conn.conf
UserParameter=count.connections,(/usr/local/bin/webgui_conn_track.sh)
 

Some collleagues suggested more efficient shell script solution for suming the overall number of connections, below is less time consuming version of script, that can be used for the calculation.
 

#!/bin/bash -x
# show FIN_WAIT2 / ESTIMATED etc. and calcuate total
count=$(netstat -n | grep "192.168.0.1" | awk ' { print $6 } ' | sort -n | uniq -c | sort -nr)
total=$((${count// /+}))
echo "$count"
echo "Total:" "$total"

 

      2 ESTABLISHED
      1 TIME_WAIT
Total: 3

 


Below is the graph built with Zabbix showing all the fluctuations from connections from monitored IP.
ebgui-check_ip_graph

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Add Zabbix time synchronization ntp userparameter check script to Monitor Linux servers

Tuesday, December 8th, 2020

Zabbix-logo-how-to-make-ntpd-time-server-monitoring-article

 

How to add Zabbix time synchronization ntp userparameter check script to Monitor Linux servers?

We needed to set on some servers at my work an elementary check with Zabbix monitoring to check whether servers time is correctly synchronized with ntpd time service as well report if the ntp daemon is correctly running on the machine. For that a userparameter script was developed called userparameter_ntp.conf the script is simplistic and few a lines of bash shell scripting 
stuff is based on gresping information required from ntpq and ntpstat common ntp client commands to get information about the status of time synchronization on the servers.
 

[root@linuxserver ]# ntpstat
synchronised to NTP server (10.80.200.30) at stratum 3
   time correct to within 47 ms
   polling server every 1024 s

 

[root@linuxserver ]# ntpq -c peers
     remote           refid      st t when poll reach   delay   offset  jitter
==============================================================================
+timeserver1 10.26.239.41     2 u  319 1024  377   15.864    1.270   0.262
+timeserver2 10.82.239.41     2 u  591 1024  377   16.287   -0.334   1.748
*timeserver3 10.82.239.43     2 u   47 1024  377   15.613   -0.553   0.251
 timeserver4 .INIT.          16 u    – 1024    0    0.000    0.000   0.000


Below is Zabbix UserParameter script that does report us 3 important values we monitor to make sure time server synchronization works as expected the zabbix keys we set are ntp.offset, ntp.sync, ntp.exact in attempt to describe what we're fetching from ntp client:

[root@linuxserver ]# cat /etc/zabbix/zabbix-agent.d/userparameter_ntp.conf

UserParameter=ntp.offset,(/usr/sbin/ntpq -pn | /usr/bin/awk 'BEGIN { offset=1000 } $1 ~ /\*/ { offset=$9 } END { print offset }')
#UserParameter=ntp.offset,(/usr/sbin/ntpq -pn | /usr/bin/awk 'FNR==4{print $9}')
UserParameter=ntp.sync,(/usr/bin/ntpstat | cut -f 1 -d " " | tr -d ' \t\n\r\f')
UserParameter=ntp.exact,(/usr/bin/ntpstat | /usr/bin/awk 'FNR==2{print $5,$6}')

In Zabbix the monitored ntpd parameters set-upped looks like this:

 

ntp_time_synchronization_check-zabbix-screenshot.

 

!Note that in above userparameter example, the commented userparameter script is a just another way to do an ntpd offset returned value which was developed before the more sophisticated with more regular expression checks from the /usr/sbin/ntpd via ntpq, perhaps if you want to extend it you can also use another script to report more verbose information to Zabbix if that is required like ouput from ntpq -c peers command:
 

UserParameter=ntp.verbose,(/usr/sbin/ntpq -c peers)

Of course to make the Zabbix fetch necessery data from monitored hosts, we need to set-up further new Zabbix Template with the respective Trigger and Items.

Below are few screenshots including the triggers used.

ntpd_server-time_synchronization_check-zabbix-screenshot-triggers

  • ntpd.trigger

{NTP:net.udp.service[ntp].last(0)}<1

  • NTP Synchronization trigger

{NTP:ntp.sync.iregexp(unsynchronised)}=1

 

 

As you can see from history we have setup our items to Store history of reported data to Zabbix from parameter script for 90 days and update our monitor check, every 30 seconds from the monitored hosts to which Tempate is applied.

Well that's all folks, time synchronization issues we'll be promptly triggering a new Alarm in Zabbix !

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Report haproxy node switch script useful for Zabbix or other monitoring

Tuesday, June 9th, 2020

zabbix-monitoring-logo
For those who administer corosync clustered haproxy and needs to build monitoring in case if the main configured Haproxy node in the cluster is changed, I've developed a small script to be integrated with zabbix-agent installed to report to a central zabbix server via a zabbix proxy.
The script  is very simple it assumed DC1 variable is the default used haproxy node and DC2 and DC3 are 2 backup nodes. The script is made to use crm_mon which is not installed by default on each server by default so if you'll be using it you'll have to install it first, but anyways the script can easily be adapted to use pcs cmd instead.

Below is the bash shell script:

UserParameter=active.dc,f=0; for i in $(sudo /usr/sbin/crm_mon -n -1|grep -i 'Node ' |awk '{ print $2 }'); do ((f++)); DC[$f]="$i"; done; \
DC=$(sudo /usr/sbin/crm_mon -n -1 | grep 'Current DC' | awk '{ print $1 " " $2 " " $3}' | awk '{ print $3 }'); \
if [ “$DC” == “${DC[1]}” ]; then echo “1 Default DC Switched to ${DC[1]}”; elif [ “$DC” == “${DC[2]}” ]; then \
echo "2 Default DC Switched to ${DC[2]}”; elif [ “$DC” == “${DC[3]}” ]; then echo “3 Default DC: ${DC[3]}"; fi


To configure it with zabbix monitoring it can be configured via UserParameterScript.

The way I configured  it in Zabbix is as so:


1. Create the userpameter_active_node.conf

Below script is 3 nodes Haproxy cluster

# cat > /etc/zabbix/zabbix_agentd.d/userparameter_active_node.conf

UserParameter=active.dc,f=0; for i in $(sudo /usr/sbin/crm_mon -n -1|grep -i 'Node ' |awk '{ print $2 }'); do ((f++)); DC[$f]="$i"; done; \
DC=$(sudo /usr/sbin/crm_mon -n -1 | grep 'Current DC' | awk '{ print $1 " " $2 " " $3}' | awk '{ print $3 }'); \
if [ “$DC” == “${DC[1]}” ]; then echo “1 Default DC Switched to ${DC[1]}”; elif [ “$DC” == “${DC[2]}” ]; then \
echo "2 Default DC Switched to ${DC[2]}”; elif [ “$DC” == “${DC[3]}” ]; then echo “3 Default DC: ${DC[3]}"; fi

Once pasted to save the file press CTRL + D


The version of the script with 2 nodes slightly improved is like so:
 

UserParameter=active.dc,f=0; for i in $(sudo /usr/sbin/crm_mon -n -1|grep -i 'Node ' |awk '{ print $2 }' | sed -e 's#:##g'); do DC_ARRAY[$f]=”$i”; ((f++)); done; GET_CURR_DC=$(sudo /usr/sbin/crm_mon -n -1 | grep ‘Current DC’ | awk ‘{ print $1 ” ” $2 ” ” $3}’ | awk ‘{ print $3 }’); if [ “$GET_CURR_DC” == “${DC_ARRAY[0]}” ]; then echo “1 Default DC ${DC_ARRAY[0]}”; fi; if [ “$GET_CURR_DC” == “${DC_ARRAY[1]}” ]; then echo “2 Default Current DC Switched to ${DC_ARRAY[1]} Please check “; fi; if [ -z “$GET_CURR_DC” ] || [ -z “$DC_ARRAY[1]” ]; then printf "Error something might be wrong with HAProxy Cluster on  $HOSTNAME "; fi;


The haproxy_active_DC_zabbix.sh script with a bit of more comments as explanations is available here 
2. Configure access for /usr/sbin/crm_mon for zabbix user in sudoers

 

# vim /etc/sudoers

zabbix          ALL=NOPASSWD: /usr/sbin/crm_mon


3. Configure in Zabbix for active.dc key Trigger and Item

active-node-switch1

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