Molecule
Molecule is a free, MIT-licensed Ansible testing framework for developing collections, playbooks, and roles.
What Molecule is
Molecule is a free, MIT-licensed Ansible testing framework for developing collections, playbooks, and roles. Its configurable workflows can provision targets, install dependencies, prepare systems, converge configurations, check idempotence, verify results, clean up, and destroy resources. Targets reachable from Ansible include containers, virtual machines, cloud infrastructure, APIs, databases, and network devices. Molecule can use static inventory files, dynamic scripts, and inventory plugins. The molecule test command runs configured sequences that may include syntax, create, converge, idempotence, and verify actions. Documentation gives continuous-integration examples for GitHub Actions, Travis CI, GitLab CI, Azure Pipelines, Jenkins Pipeline, and Tox. Installation is through pip, with ansible-dev-tools recommended; Molecule is also in its container image. It requires a recent ansible-core and supports only the latest two major Ansible versions. The delegated driver is default, while other drivers are installed separately. It runs locally and supports AWS, Azure, and GCP targets.
Good
- Configurable end-to-end test workflows
- Supports containers, clouds, APIs, and devices
- Uses existing Ansible inventory sources
- CI examples cover several platforms
- MIT licensed and free
Watch out
- Supports only latest two Ansible majors
- ansible-lint requires separate installation
- pip is the only supported installation method
- Drivers may need extra packages
Who it suits
Molecule suits Ansible role, playbook, and collection developers who need repeatable provisioning and verification workflows. It is also relevant to teams integrating those tests into continuous integration.
Verdict
Molecule provides a structured way to test Ansible automation across local and remote targets. Its version window and separate ansible-lint requirement should be considered during setup.
The facts
Each one read from Molecule's own pages, with the date it was checked.
What it does
- Ansible versions
- Molecule supports only the latest two major versions of Ansible (N/N-1).checked 5 Oct 2026
- Ansible version support
- Molecule supports only the latest two major versions of Ansible.checked 5 Oct 2026
- CI
- The documentation gives a GitHub Actions example that installs dependencies and runs `molecule test`.checked 5 Oct 2026
- CI integrations
- The documentation provides continuous integration examples for GitHub Actions, Travis CI, GitLab CI, Azure Pipelines, Jenkins Pipeline, and Tox.checked 5 Oct 2026
- Command line
- Molecule can be invoked with the molecule command or as a Python module using python3 -m molecule.checked 5 Oct 2026
- Container option
- Molecule is included in the Ansible Development Tools container image.checked 5 Oct 2026
- Drivers
- Molecule uses the delegated driver by default, and other drivers can be installed separately, most through the molecule-plugins package.checked 5 Oct 2026
- Installation
- The documentation names pip as the only supported installation method and recommends installing Molecule through the ansible-dev-tools package.checked 5 Oct 2026
- Integrations
- Molecule uses Ansible features such as inventory, playbooks, and collections, and community drivers are available through molecule-plugins.checked 5 Oct 2026
- Inventory
- Molecule can use existing Ansible inventory sources, including static files, dynamic scripts, and inventory plugins.checked 5 Oct 2026
- License
- The project GitHub page identifies Molecule as MIT licensed.checked 5 Oct 2026
- Notable limitation
- Molecule does not include ansible-lint; the installation documentation instructs users to install it separately.checked 5 Oct 2026
- Pricing
- The project documentation provides pip installation instructions and does not list a paid plan or price.checked 5 Oct 2026
- Purpose
- Molecule is an Ansible testing framework for developing and testing collections, playbooks, and roles.checked 5 Oct 2026
- Requirements
- Molecule requires a recent supported version of ansible-core, and selected drivers may require additional operating system packages or Python packages.checked 5 Oct 2026
- Security
- The documentation recommends installing Molecule in a virtual environment and notes a possible issue on SELinux-supporting systems when installed into one.checked 5 Oct 2026
- Support
- The project directs users to the Ansible community forum for questions and help, and says possible security bugs can be reported to [email protected].checked 5 Oct 2026
- Test targets
- Test scenarios can target systems and services reachable from Ansible, including containers, virtual machines, cloud infrastructure, APIs, databases, and network devices.checked 5 Oct 2026
- Test workflows
- Its configurable actions include provisioning, dependency installation, preparation, convergence, idempotence checks, verification, cleanup, and destruction.checked 5 Oct 2026
- Who it is for
- The getting-started guides direct Ansible role, playbook project, and collection developers to different testing paths.checked 5 Oct 2026
- Workflow
- The `molecule test` command runs a configurable sequence of testing actions, including syntax, create, converge, idempotence, and verify.checked 5 Oct 2026
The company
- Founded
- 2015checked 28 Sep 2026
Where it runs
- Platform requirements
- Installation requires Python packaging and Python management on the system running Molecule, and the documentation gives package installation examples for CentOS and Ubuntu.checked 5 Oct 2026
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