Ansible Molecule with systemd in docker

readme.md

This gist describes how to run systemd within a container (podman or docker) created by the ansible testing framework molecule.

Folder structure

The files in this gist need to be placed into the following structure:

📂 .
├── 📂 molecule
│   ├── 📂 default
│   │   ├── 🗒 converge.yml
│   │   └── 🗒 molecule.yml
│   └── 🗒 requirements.txt
├── 🗒 ansible-lint.yml
└── 🗒 yamllint.yml

Molecule prefers running containers with podman. To configure the prefered container runtime set the environment variable MOLECULE_CONTAINERS_BACKEND=podman,docker.

Installation within a python virtual environment

python3 -m venv --copies molecule
source molecule/bin/activate
# Updating all python packages within the venv
python3 -m pip list --outdated --format=json | jq -r '.[] | "\(.name)==\(.latest_version)"' | xargs --no-run-if-empty -n1 python3 -m pip install -U
# Installing molecule and dependencies
python3 -m pip install -r molecule/requirements.txt

Building scenario

MOLECULE_CONTAINERS_BACKEND=docker molecule create
# or
MOLECULE_CONTAINERS_BACKEND=podman molecule create

Linting

molecule lint

Testing / running playbooks

molecule converge

Logging into virtual machine

molecule login -h instance-1

Idempotence test

molecule idempotence

Destroying scenario

molecule destroy

Everything in one step, without possible login

molecule test

ansible-lint.yml

---
parseable: true
skip_list:
  - skip_ansible_lint
  - "403"
  - "204"
  - no-handler
  - empty-string-compare
  - var-naming
  - name[casing]

warn_list:
  - risky-shell-pipe
  - ignore-errors
# exclude_paths:

converge.yml

---
- name: Converge
  hosts: all
  tasks:
  
    - name: Installing | nginx
      ansible.builtin.package:
        name: nginx
        state: present

    - name: Configuring | systemd | Enabling and starting nginx
      ansible.builtin.systemd:
        name: nginx
        enabled: true
        state: started
        daemon_reload: true

molecule.yml

---
dependency:
  name: galaxy
driver:
  name: containers
lint: |
  set -e
  yamllint -c ./yamllint.yml ./*.yml ./molecule/
  ansible-lint -c ./ansible-lint.yml ./*.yml ./molecule/*/*.yml -v
platforms:
  - name: instance-1
    image: "docker.io/geerlingguy/docker-${MOLECULE_DISTRO:-centos8}-ansible:latest"
    command: ${MOLECULE_DOCKER_COMMAND:-""}
    ### Docker specific begin
    docker_networks:
      - name: dremio
    networks:
      - name: dremio
    ### Docker specific end
    ### Podman specific begin
    network: dremio
    ### Podman specific end
    ### Systemd preparation begin
    volumes:
      - /sys/fs/cgroup:/sys/fs/cgroup:ro
    tmpfs:
      - /run
      - /tmp
    ### Systemd preparation end
    privileged: false
    pre_build_image: true
    groups:
      - webserver
provisioner:
  name: ansible
  playbooks:
    converge: ${MOLECULE_PLAYBOOK:-converge.yml}
  config_options:
    defaults:
      interpreter_python: auto_silent
      callbacks_enabled: profile_tasks, timer, yaml
    connection:
      pipelining: true
    ssh_connection:
      scp_if_ssh: true
  env:
    PY_COLORS: 1
  inventory:
    host_vars:
      instance-1:
        zookeeper_id: 1
        postgres_port: 5433
verifier:
  name: ansible

requirements.yml

ansible-core==2.13.8
yamllint==1.30.0
molecule-plugins[docker,podman]==23.0.0
molecule==4.0.4
ansible-lint==6.14.2
paramiko==3.0.0  # https://github.com/ansible/creator-ee/issues/140

yamllint.yml

---
# Based on ansible-lint config
extends: default

# ignore: |

rules:
  braces:
    max-spaces-inside: 1
    level: error
  brackets:
    max-spaces-inside: 1
    level: error
  colons:
    max-spaces-after: -1
    level: error
  commas:
    max-spaces-after: -1
    level: error
  comments:
    require-starting-space: false
  #  comments: disable
  comments-indentation: disable
  #  document-start: disable
  empty-lines:
    max: 3
    level: error
  hyphens:
    level: error
  #  indentation: disable
  key-duplicates: enable
  line-length: disable
  #  new-line-at-end-of-file: disable
  new-lines:
    type: unix
  #  trailing-spaces: disable
  truthy: disable