CheckMk: Use Docker Compose for CheckMk

CheckMk is a great tool for monitoring. It's quite easy to deploy, and it offers support for monitoring a big range of hardware and software solutions - either through plugins, or out of the box.

To create a CheckMk container, you can use this docker-compose.yml:

services:
  checkmk:
    image: checkmk/check-mk-raw:2.2.0-latest
    tmpfs: /opt/omd/sites/cmk/tmp:uid=1000,gid=1000
    volumes:
      - ./monitoring:/omd/sites
      - /etc/localtime:/etc/localtime:ro
    ports:
      - 5000:5000
      - 8000:8000
    restart: always

This image will only work on x86_64.

Then, the image will be pulled and the container started:

# docker compose pull
# docker compose up -d

[+] Pulling 7/7
 ✔ checkmk Pulled                                                                            243.7s
   ✔ 43f89b94cd7d Pull complete                                                               17.9s
   ✔ c333a7cd7991 Pull complete                                                               18.0s
   ✔ f1a8ddf7a047 Pull complete                                                              100.5s
   ✔ c3b68830a381 Pull complete                                                              110.9s
   ✔ cdb87fce6a90 Pull complete                                                              241.8s
   ✔ c04a97edb62a Pull complete                                                              241.9s
[+] Running 2/2
 ✔ Network checkmk_default      Created                                                        0.6s
 ✔ Container checkmk-checkmk-1  Started                                                        3.2s

The logs show what happens:

# docker compose logs -f

checkmk-1  | ### CREATING SITE 'cmk'
checkmk-1  | Generating configuration for core (type nagios)...
checkmk-1  | Precompiling host checks...OK
checkmk-1  | Adding /opt/omd/sites/cmk/tmp to /etc/fstab.
checkmk-1  | Going to set TMPFS to off.
checkmk-1  | Temporary filesystem already mounted
checkmk-1  | Updating core configuration...
checkmk-1  | Executing post-create script "01_create-sample-config.py"...OK
checkmk-1  | Adding /opt/omd/sites/cmk/tmp to /etc/fstab.
checkmk-1  | Going to set TMPFS to off.
checkmk-1  | Created new site cmk with version 2.2.0p37.cre.
checkmk-1  |
checkmk-1  |   The site can be started with omd start cmk.
checkmk-1  |   The default web UI is available at http://checkmk/cmk/
checkmk-1  |
checkmk-1  |   The admin user for the web applications is cmkadmin with password: XxXxXxXx
checkmk-1  |   For command line administration of the site, log in with 'omd su cmk'.
checkmk-1  |   After logging in, you can change the password for cmkadmin with 'cmk-passwd cmkadmin'.
checkmk-1  |
checkmk-1  | WARNING: You have to execute 'omd update-apache-config cmk' as root to update and apply the configuration of the system apache.
checkmk-1  | WARNING: You have to execute 'omd update-apache-config cmk' as root to update and apply the configuration of the system apache.
checkmk-1  | ### STARTING XINETD
checkmk-1  |  * Starting internet superserver xinetd
checkmk-1  |    ...done.
checkmk-1  | ### STARTING SITE
checkmk-1  | Starting agent-receiver...OK
checkmk-1  | Starting mkeventd...OK
checkmk-1  | Starting rrdcached...OK
checkmk-1  | Starting npcd...OK
checkmk-1  | Starting nagios...OK
checkmk-1  | Starting apache...OK
checkmk-1  | Starting redis...OK
checkmk-1  | Initializing Crontab...OK
checkmk-1  | Temporary filesystem already mounted
checkmk-1  | ### STARTING CRON
checkmk-1  | ### CONTAINER STARTED

Now, CheckMk is available, using the port 5000.

Login is cmkadmin, password can be taken from the log files:

checkmk-1  |   The admin user for the web applications is cmkadmin with password: XxXxXxXx

To install a CheckMk agent, we can use the link from Setup -> Linux -> Packaged Agents. It's available for DEB and RPM based distributions, using Setup -> Windows -> Packaged Agents there's also an MSI package for Windows.

Download links for the agent look like that:

http://<hostname>:5000/cmk/check_mk/agents/check-mk-agent_2.2.0p37-1_all.deb
http://<hostname>:5000/cmk/check_mk/agents/check-mk-agent-2.2.0p37-1.noarch.rpm
http://<hostname>:5000/cmk/check_mk/agents/windows/check_mk_agent.msi

After installation, we can add the host to CheckMk. And monitoring begins...