Rolecule

Description

rolecule is a simple tool to help you test your ansible roles by creating systemd enabled containers with either docker or podman, then converging them with ansible. We're basically treating containers as mini VMs.

Once converged, it will run a verifier to test it all. Currently, the only supported provisioner is goss, but others may be added at some point in the future.

This should speed up testing your roles if you're currently using local or remote virtual machines.

Usage

First, you need to create a simple rolecule.yml file in either the root of your role or in the tests directory, e.g.:

---
engine:
  name: podman

provisioner:
  name: ansible

verifier:
  name: goss

instances:
  - name: rockylinux-9.1
    image: rockylinux-systemd:9.1
  - name: ubuntu-22.04
    image: ubuntu-systemd:22.04

Then, from the root of your role (e.g. sshd), run rolecule test, e.g.:

» rolecule test
   • creating container rolecule-sshd-rockylinux-9.1 with podman
   • creating container rolecule-sshd-ubuntu-22.04 with podman
   • converging container rolecule-sshd-rockylinux-9.1 with ansible
Using /etc/ansible/ansible.cfg as config file

PLAY [test] ********************************************************************
...

PLAY RECAP *********************************************************************
localhost                  : ok=5    changed=4    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0

   • converging container rolecule-sshd-ubuntu-22.04 with ansible
No config file found; using defaults

PLAY [test] ********************************************************************
...

PLAY RECAP *********************************************************************
localhost                  : ok=5    changed=4    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0

   • verifying container rolecule-sshd-rockylinux-9.1 with goss
............

Total Duration: 0.016s
Count: 12, Failed: 0, Skipped: 0

   • verifying container rolecule-sshd-ubuntu-22.04 with goss
............

Total Duration: 0.015s
Count: 12, Failed: 0, Skipped: 0

   • destroying container rolecule-sshd-rockylinux-9.1
   • destroying container rolecule-sshd-ubuntu-22.04
   • complete

Help

» rolecule --help
rolecule uses docker or podman to test your
configuration management roles/recipes/modules in a systemd enabled container,
then tests them with a verifier (goss/testinfra).

Usage:
  rolecule [command]

Available Commands:
  completion  Generate the autocompletion script for the specified shell
  converge    Run your configuration management tool to converge the container(s)
  create      Create a new container(s) to test the role in
  destroy     Destroy everything
  help        Help about any command
  list        List the running containers for this role/module/recipe
  shell       Open a shell in a container
  test        Create the container(s), converge them, test them, then clean up
  verify      Verify your containers are configured how you expect

Flags:
  -d, --debug   enable debug output
  -h, --help    help for rolecule

Use "rolecule [command] --help" for more information about a command.

Individual sub command examples

Create the containers:

» rolecule create
   • creating container rolecule-sshd-rockylinux-9.1 with podman
   • creating container rolecule-sshd-ubuntu-22.04 with podman

List all containers:

» rolecule list
CONTAINER ID  IMAGE                             COMMAND         CREATED         STATUS             PORTS       NAMES
e9638f571210  localhost/rockylinux-systemd:9.1  /usr/sbin/init  21 minutes ago  Up 21 minutes ago              rolecule-sshd-rockylinux-9.1
0e07e4214fd5  localhost/ubuntu-systemd:22.04                    21 minutes ago  Up 21 minutes ago              rolecule-sshd-ubuntu-22.04

Open a shell:

» rolecule shell -n rolecule-sshd-ubuntu-22.04
root@0e07e4214fd5:/src#

Destroy the containers:

» rolecule destroy
   • destroying container rolecule-sshd-rockylinux-9.1
   • destroying container rolecule-sshd-ubuntu-22.04

Provisioners

Ansible

The default for the ansible provisioner is the equivalent to setting the following in the rolecule.yml config file:

provisioner:
  name: ansible
  command: ansible-playbook
  playbook: playbook.yml
  args:
    - --connection
    - local
    - --inventory
    - localhost,
    - tests/playbook.yml
  extra_args: []
  env:
    ANSIBLE_ROLES_PATH: .
    ANSIBLE_NOCOWS: True

If you want to add extra environment variables you can just add them to the env map, e.g.:

provisioner:
  name: ansible
  env:
    ANSIBLE_NOCOLOR: True

If you want to run a completely different ansible command, you can override the command and all the args with the command and args keys respectively, but if you just want to add other args like --diff or --verbose, add them to the extra_args array, e.g.:

provisioner:
  name: ansible
  extra_args:
    - --diff
    - --verbose

Role dependencies

If you have role dependencies in your meta/main.yml file using local roles in the same location as the current role, they will be mounted at /etc/ansible/roles in the container so ansible can find them.

Instances

These are instances of each test scenario, allowing you to test different ansible tags with specific test files.

A simple example for a single Ubuntu test would be:

instances:
  - name: ubuntu-22.04
    image: ubuntu-systemd:22.04

Something more elaborate:

instances:
  - name: ubuntu-22.04
    image: ubuntu-systemd:22.04
    playbook: ubuntu/playbook.yml
    volumes:
      - /var/run/docker.sock:/var/run/docker.sock
  - name: ubuntu-22.04-build
    image: ubuntu-systemd:22.04
    arch: amd64
    playbook: ubuntu/playbook.yml
    testfile: goss-build.yaml
    tags:
      - build
  - name: rockylinux-9.1
    image: rockylinux-systemd:9.1
  - name: rockylinux-9.1-build
    image: rockylinux-systemd:9.1
    testfile: goss-build.yaml
    tags:
      - build
    skip_tags:
      - provision

Where the above will test two different scenarios for each of the Ubuntu and Rocky Linux containers.

If you do not specify the testfile in the instance config, it will use the one specified in the verifier config.

If you do not specify the playbook in the instance config, it will use the one specified in the provisioner config.

Testing multiple architectures is support, but untested as I don't currently have an easy way to test it, but should be as simple as something like:

instances:
  - name: ubuntu-22.04-amd64
    image: ubuntu-systemd:22.04
    arch: amd64
  - name: ubuntu-22.04-arm64
    image: ubuntu-systemd:22.04
    arch: arm64

If you don't specify the arch, it will use the current host's architecture

Please note that id you do want to test using a different architecture to the host your are running it on, you will need to have the relevant container image for that architecture.

Verifiers

Goss

The default goss configuration when you only specify the name, is equivalent to this:

verifier:
  name: goss
  testfile: goss.yaml
  extra_args: []

This will execute:

goss --gossfile tests/goss.yaml validate

If you want to customise how goss validate is executed, you can change the gossfile and add extra arguments to the validate subcommand, e.g. with this in your rolecule.yml:

verifier:
  name: goss
  testfile: goss-build.yaml
  extra_args:
    - --format
    - tap

It will execute:

goss --gossfile tests/goss-build.yaml validate --format tap

FAQ

How do I get this working on macOS?

You'll need to make sure you create a rootful podman machine with your home directory mounted for volume mounts to work, e.g.:

» podman machine init --now --rootful -v $HOME:$HOME

Docker Desktop should just work

How do I get this working on Windows?

You'll need to make sure you create a rootful podman machine, e.g.:

» podman machine init --now --rootful

Docker Desktop should just work

How do I create a suitable container image for this?

You can use the Dockerfile files in the testing directory to build suitable images:

» podman build -t rockylinux-systemd:9.1 -f testing/ansible/rockylinux-9.1-systemd.Dockerfile .
» podman build -t ubuntu-systemd:22.04 -f testing/ansible/ubuntu-22.04-systemd.Dockerfile .
» podman build -t amazonlinux2-systemd:2 -f testing/ansible/amazonlinux2-systemd.Dockerfile .

or

» docker build -t rockylinux-systemd:9.1 -f testing/ansible/rockylinux-9.1-systemd.Dockerfile .
» docker build -t ubuntu-systemd:22.04 -f testing/ansible/ubuntu-22.04-systemd.Dockerfile .
» docker build -t amazonlinux2-systemd:2 -f testing/ansible/amazonlinux2-systemd.Dockerfile .

How do I install collections?

For now, I've been building in my collections in to the container images in the default location so they are discovered automatically by ansible.

TODO

• Test with podman on Mac
• Test docker on Linux
• Make provisioner output unbuffered
• Support installing role dependencies
• Support installing ansible collections
• Support testinfra verifier
• Support scenarios, making it possible to test a role with different tags
• Support using custom provisioner command/args/env vars from rolecule.yml
• Support using custom verifier command/args/env vars from rolecule.yml/%s
• Implement rolecule init to generate a rolecule.yml file (use current directory structure to determine configuration management provisioner)
• Implement rolecule list subcommand to list all running containers
• Write some tests :/
• Document what is required for a container image
• Test with docker on Linux
• Test with docker desktop on Mac
• Test with podman desktop on Windows
• Test with docker desktop on Windows
• Add goreleaser config to release to Github Releases
• Add Github actions workflow to build, test and release