docker-centos9-systemd

A minimal systemd enabled centos9 Docker image for testing Ansible roles with Molecule.

NOTE: This image does NOT contain Ansible tooling, e.g. ansible-core or yamllint. Thus, the use case is as target host for Ansible controllers or within the Molecule create/converge/test cycle.

Docker Pull Command

docker pull trfore/docker-centos9-systemd

How to Build

This image is built on Docker Hub automatically any time the upstream OS image is rebuilt, and any time a commit is made or merged to the main branch. But if you need to build the image on your own locally, do the following:

1. Install docker
2. Clone the repo, git clone https://github.com/trfore/docker-centos9-systemd.git
3. cd into the directory
4. Run docker build --tag trfore/docker-centos9-systemd .

How to Use

Within Molecule Scenario

• Add the following code to your molecule scenario file, e.g. molecule/default/molecule.yml.

  platforms:
    - name: instance
      image: trfore/docker-centos9-systemd:latest
      tmpfs:
        - /run
        - /tmp
      volumes:
        - /sys/fs/cgroup:/sys/fs/cgroup:rw
      cgroupns_mode: host
      privileged: true
      pre_build_image: true

Interactively Using Docker

• Install docker

• Build an image locally (see above) or pull from Docker Hub: docker pull trfore/docker-centos9-systemd:latest

• Run a container from the image:

  docker run -d -it --name centos9-systemd --privileged --cgroupns=host --tmpfs=/run --tmpfs=/tmp --volume=/sys/fs/cgroup:/sys/fs/cgroup:rw trfore/docker-centos9-systemd:latest

• Use it, example:

  docker exec -it centos9-systemd /bin/bash

Using Podman

• Podman defaults to running containers in systemd mode, --systemd=true, and will mount the required tmpfs and cgroup filesystem. See Podman Docs: Commands run --systemd for details.

  podman run -d -it --name centos9-systemd docker.io/trfore/docker-centos9-systemd:latest

Additional Images

Base OS	Github	Docker Hub
CentOS Stream 8	docker-centos8-systemd	trfore/docker-centos8-systemd
CentOS Stream 9	docker-centos9-systemd	trfore/docker-centos9-systemd
Debian 10	docker-debian10-systemd	trfore/docker-debian10-systemd
Debian 11	docker-debian11-systemd	trfore/docker-debian11-systemd
Debian 12	docker-debian12-systemd	trfore/docker-debian12-systemd
Ubuntu 20.04	docker-ubuntu2004-systemd	trfore/docker-ubuntu2004-systemd
Ubuntu 22.04	docker-ubuntu2204-systemd	trfore/docker-ubuntu2204-systemd
Ubuntu 24.04	docker-ubuntu2404-systemd	trfore/docker-ubuntu2404-systemd

Maintainers

Taylor Fore (https://github.com/trfore)

Acknowledgements

Inspired by Jeff Geerling's (@geerlingguy), CentOS 8, Debian 10/11, and Ubuntu 20/22 docker images for ansible, geerlingguy/docker-*-ansible.

References

• https://molecule.readthedocs.io/en/stable/index.html
• https://molecule.readthedocs.io/en/stable/examples.html#systemd-container
• https://developers.redhat.com/blog/2016/09/13/running-systemd-in-a-non-privileged-container
• github runner - ubuntu 20.04 preinstalled software
• github runner - ubuntu 22.04 preinstalled software