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Install Naemon Core on CentOS 8

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Prepare your system

In this how to, we are going to install all files to /opt/naemon.

If you want to delete Naemon Core, just remove this folder and the systemd config.

All commands needs to run as user root or via sudo.

useradd -r naemon

Install dependencies

yum install epel-release
yum check-update

yum group install "Development Tools"
yum install glib2-devel wget sudo
dnf --enablerepo=PowerTools install gperf help2man

Download and install Naemon Core

Check for new versions

In this how to I use Naemon 1.1.0. Check if there is a new version available! 

cd /tmp/
wget https://github.com/naemon/naemon-core/archive/v1.1.0.tar.gz
tar xfv v1.1.0.tar.gz
cd naemon-core-1.1.0/

./autogen.sh --prefix=/opt/naemon --with-naemon-user=naemon --with-naemon-group=naemon --with-pluginsdir=/usr/lib64/nagios/plugins
make all
make install

mkdir -p /opt/naemon/var/
mkdir -p /opt/naemon/var/cache/naemon
mkdir -p /opt/naemon/var/spool/checkresults
chown naemon:naemon /opt/naemon/var -R

mkdir /opt/naemon/etc/naemon/module-conf.d
chown naemon:naemon /opt/naemon/etc -R

Start Naemon Core (through systemd - recommended)

Due to I had some issues using the default Naemon systemd service configuration I modified the original a bit.

Copy the following to the file /lib/systemd/system/naemon.service using your favorite editor.

Pitfall!

If you want to use Naemon with the Statusengine Broker Module, it is required that the Gearman Job Server is running, BEFORE your Naemon gets started!
So you need to make sure that systemd will start the Gearman Job Server first.
To configure this, replace the AFTER= line in the following systemd configuration with this: 

After=network.target gearmand.service
If not already done, install the Gearman Job Server now! 
yum install gearmand
systemctl enable gearmand
systemctl start gearmand

[Unit]
Description=Naemon Monitoring Daemon
Documentation=http://naemon.org/documentation
After=network.target

[Service]
Type=forking
PIDFile=/opt/naemon/var/cache/naemon/naemon.pid
ExecStartPre=/opt/naemon/bin/naemon --verify-config /opt/naemon/etc/naemon/naemon.cfg
ExecStart=/opt/naemon/bin/naemon --daemon /opt/naemon/etc/naemon/naemon.cfg
ExecReload=/bin/kill -HUP $MAINPID
User=naemon
Group=naemon
StandardOutput=journal
StandardError=inherit

[Install]
WantedBy=multi-user.target


systemctl daemon-reload
systemctl start naemon

Now you can check if your Naemon Core is running using systemctl status naemon:

[root@centos8 naemon-core-1.1.0]# systemctl status naemon
● naemon.service - Naemon Monitoring Daemon
   Loaded: loaded (/usr/lib/systemd/system/naemon.service; disabled; vendor preset: disabled)
   Active: active (running) since Tue 2019-12-24 13:03:49 UTC; 4s ago
     Docs: http://naemon.org/documentation
  Process: 10163 ExecStart=/opt/naemon/bin/naemon --daemon /opt/naemon/etc/naemon/naemon.cfg (code=exited, status=0/SUCCESS)
  Process: 10162 ExecStartPre=/opt/naemon/bin/naemon --verify-config /opt/naemon/etc/naemon/naemon.cfg (code=exited, status=0/SUCCESS)
 Main PID: 10164 (naemon)
    Tasks: 14 (limit: 26213)
   Memory: 5.7M
   CGroup: /system.slice/naemon.service
           ├─10164 /opt/naemon/bin/naemon --daemon /opt/naemon/etc/naemon/naemon.cfg
           ├─10165 /opt/naemon/bin/naemon --worker /opt/naemon/var/naemon.qh
           ├─10166 /opt/naemon/bin/naemon --worker /opt/naemon/var/naemon.qh
           ├─10167 /opt/naemon/bin/naemon --worker /opt/naemon/var/naemon.qh
           ├─10168 /opt/naemon/bin/naemon --worker /opt/naemon/var/naemon.qh
           ├─10169 /opt/naemon/bin/naemon --worker /opt/naemon/var/naemon.qh
           ├─10170 /opt/naemon/bin/naemon --worker /opt/naemon/var/naemon.qh
           ├─10171 /opt/naemon/bin/naemon --worker /opt/naemon/var/naemon.qh
           ├─10172 /opt/naemon/bin/naemon --worker /opt/naemon/var/naemon.qh
           ├─10173 /opt/naemon/bin/naemon --worker /opt/naemon/var/naemon.qh
           ├─10174 /opt/naemon/bin/naemon --worker /opt/naemon/var/naemon.qh
           ├─10175 /opt/naemon/bin/naemon --worker /opt/naemon/var/naemon.qh
           ├─10176 /opt/naemon/bin/naemon --worker /opt/naemon/var/naemon.qh
           └─10177 /opt/naemon/bin/naemon --daemon /opt/naemon/etc/naemon/naemon.cfg

Dec 24 13:03:49 centos8 systemd[1]: Starting Naemon Monitoring Daemon...
Dec 24 13:03:49 centos8 systemd[1]: Started Naemon Monitoring Daemon.
[root@centos8 naemon-core-1.1.0]#

To make sure that you Naemon will start automatically on boot, you need to enable the systemd configuration:

systemctl enable naemon.service

Install Nagios Plugins

By default, Naemon will install a sample config with some basic checks. So you need to install the nagios plugins to get them to work.

At the time writing this article the package nagios-plugins-all has unmet dependencies to the package nagios-plugins-disk_smb. For this reason we pick the plugins we need manually.

yum install nagios-plugins-{load,http,users,procs,disk,swap,nrpe,uptime,dns,ssh,dhcp,icmp,ping,snmp,dummy,by_ssh,tcp}

Setup Logrotate

To avoid, that the size of your naemon.log grows up in the sky you should configure the logrotate daemon.

Modify the file /opt/naemon/etc/logrotate.d/naemon until it fulfill your needs.

Than copy it to /etc/logrotate.d/ to enable the configuration


Congrats! You installed Naemon Core!

Load Statusengine Broker Module

Now you are ready to install and load the Statusengine Broker Module.

Start Naemon in foreground (expert or debugging)

For some reasons it can be useful to run Naemon in foreground.

You can do this with this command /opt/naemon/bin/naemon /opt/naemon/etc/naemon/naemon.cfg

[root@centos8 naemon-core-1.1.0]# sudo -u naemon /bin/bash
bash-4.4$ /opt/naemon/bin/naemon /opt/naemon/etc/naemon/naemon.cfg

Naemon Core 1.1.0.source
Copyright (c) 2013-present Naemon Core Development Team and Community Contributors
Copyright (c) 2009-2013 Nagios Core Development Team and Community Contributors
Copyright (c) 1999-2009 Ethan Galstad
License: GPL

Website: http://www.naemon.org
Naemon 1.1.0.source starting... (PID=10240)
Local time is Tue Dec 24 13:06:05 UTC 2019
qh: Socket '/opt/naemon/var/naemon.qh' successfully initialized
nerd: Channel hostchecks registered successfully
nerd: Channel servicechecks registered successfully
nerd: Fully initialized and ready to rock!
Successfully launched command file worker with pid 10253
^CCaught 'Interrupt', shutting down...
Retention data successfully saved.
Successfully shutdown... (PID=10240)
Event broker module 'NERD' deinitialized successfully.
Successfully reaped command worker (PID = 10253)
bash-4.4$