CheckMK Plugins

Collection of CheckMK monitoring plugins for Linux servers. Tested only on Debian.

Plugins

Plugin	Type	Description
fail2ban.sh	local check	Monitor fail2ban — CRITICAL if stopped, reports total banned IPs and per-jail list
imap.sh	local check	Check IMAP service availability via telnet
debian.sh	local check	Check Debian version age and last dist-upgrade date
samba.sh	local check	Count connected Samba clients and open files
backup.sh	local check	Check backup freshness via logrotate status files on NAS (hourly cache)
qemu.sh	local check	Monitor QEMU/KVM virtual machines (state, memory, CPU)
virsh-backup.sh	local check	Check VM backup status and list backup data files (hourly cache)
nut.sh	agent plugin	Dump UPS status via NUT (section <<<nut>>>)
mk_mysql	agent plugin	MySQL/MariaDB monitoring — ping, global status/variables (sections <<<mysql_ping>>>, <<<mysql>>>). Based on original Checkmk plugin with capacity and replica sections removed

Installation

Local checks

sudo mkdir -p /usr/lib/check_mk_agent/local /usr/lib/check_mk_agent/local/3600
sudo wget https://raw.githubusercontent.com/rollopack/checkmk-plugin/main/fail2ban.sh -O /usr/lib/check_mk_agent/local/fail2ban.sh && sudo chmod 755 /usr/lib/check_mk_agent/local/fail2ban.sh
sudo wget https://raw.githubusercontent.com/rollopack/checkmk-plugin/main/imap.sh -O /usr/lib/check_mk_agent/local/imap.sh && sudo chmod 755 /usr/lib/check_mk_agent/local/imap.sh
sudo wget https://raw.githubusercontent.com/rollopack/checkmk-plugin/main/debian.sh -O /usr/lib/check_mk_agent/local/debian.sh && sudo chmod 755 /usr/lib/check_mk_agent/local/debian.sh
sudo wget https://raw.githubusercontent.com/rollopack/checkmk-plugin/main/samba.sh -O /usr/lib/check_mk_agent/local/samba.sh && sudo chmod 755 /usr/lib/check_mk_agent/local/samba.sh
sudo wget https://raw.githubusercontent.com/rollopack/checkmk-plugin/main/backup.sh -O /usr/lib/check_mk_agent/local/3600/backup.sh && sudo chmod 755 /usr/lib/check_mk_agent/local/3600/backup.sh
sudo wget https://raw.githubusercontent.com/rollopack/checkmk-plugin/main/qemu.sh -O /usr/lib/check_mk_agent/local/qemu.sh && sudo chmod 755 /usr/lib/check_mk_agent/local/qemu.sh
sudo wget https://raw.githubusercontent.com/rollopack/checkmk-plugin/main/virsh-backup.sh -O /usr/lib/check_mk_agent/local/3600/virsh-backup.sh && sudo chmod 755 /usr/lib/check_mk_agent/local/3600/virsh-backup.sh

The 3600 subdirectory caches both backup checks for one hour. If either script is already installed directly in local/, move it to local/3600/ rather than keeping both copies, to avoid running the same check twice.

Agent plugins

sudo wget https://raw.githubusercontent.com/rollopack/checkmk-plugin/main/nut.sh -O /usr/lib/check_mk_agent/plugins/nut.sh && sudo chmod 755 /usr/lib/check_mk_agent/plugins/nut.sh
sudo wget https://raw.githubusercontent.com/rollopack/checkmk-plugin/main/mk_mysql -O /usr/lib/check_mk_agent/plugins/mk_mysql && sudo chmod 755 /usr/lib/check_mk_agent/plugins/mk_mysql

Additional setup

fail2ban — sudoers

The fail2ban.sh check requires passwordless sudo for the checkmk user. Create /etc/sudoers.d/checkmk with:

checkmk ALL=(root) NOPASSWD: /usr/bin/fail2ban-client

Service discovery

After installing the plugins, run service discovery on the CheckMK server:

cmk -I --all
cmk -R

License

GNU General Public License v3.0

Copyright (C) 2026 Rolland Gabriel (https://github.com/rollopack)