Monitoring with Checkmk and Docker

Overview

• Errors
  • "Pool overlaps with other one on this adress space"
• Container
  • Build Container
• Monitoring
  • Add hosts
  • Add a monitoring rule
  • Monitor Postgres database
• Other
  • Bash access
  • Database access
  • Container network diagram

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ERROR: Pool overlaps with other one on this address space

• run: docker network prune
• Rebuild Container

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Build Container

docker-compose -f "docker-compose.yml" up -d --build

or open folder in VSC, (if you have docker extension) right click on docker-compose.yml and click Compose Restart

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Add Host System to monitoring

• "Setup"
• "Hosts"

• "Add hosts to the monitoring"

• Hostname -> localhost

• "Save & go to service configuration"

• Add every service

• Click on Changes in top right

• "Activate on selected sites"

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Add a monitoring rule for postgres

• "Setup"
• "Services"
• "Service Monitoring rules"
• CTRL + F "PostgreSQL Database Statistics"
• Select this option
• "Create Rule in Folder: Main directory"
• Set "postgres" as description
• Under Value enable every option and set prefered values

• Add every Host that hosts the postgres database to "Explicit Hosts"
• Re-run a Full Service Scan on the host the database is on

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Monitor Postgres Database with this container

• Make sure you downloaded psql on default location (version 14.1 as of current time)
• Only install the Command Line Tools!

• Make sure your host system has the Windows agent installed under default location (should be C:\ProgramData\checkmk\), you can find and download the installer under localhost:8080 when the container is running, in Setup > Agents > Windows > .msi
• download this python script at C:\ProgramData\checkmk\agent\plugins\mk_postgres.py
• make sure you have python installed and run this script in a console opened at the directory this script is saved with my_postgres.py

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Bash access

• run docker ps to see active docker containers
• copy container ID
• run docker exec -it <id> bash (replace "<id>" with container ID) or instead of id use checkmk_<hostname>_1

Database access

• go on site localhost:8081
• server: 192.10.100.3
• username: postgres
• password: <empty>
• databse: <empty>

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Network Diagram

Name	Hostname	IPv4	Ports	Function
Checkmk	checkmk	192.10.100.2	8080 & 5000	Monitoring
Postgres	postgres	192.10.100.3	5432	Database
Adminer	adminer	192.10.100.4	8081 & 8080	User Interface
Host System	localhost	127.0.0.1	6556	Client System