How to Cleanly Uninstall Ansible

How to test install and uninstall scenario with Molecule for Ansible?

Recommended Solution

The recommended way to address this is using multiple Molecule Scenarios. You could use your install scenario as the default, and then add a second uninstall scenario that just runs and tests the uninstall steps.

When setting this up, simply create a second scenario directory in your role's molecule folder (copy the default one), and then make some changes:

• (Edit: this step was necessary for molecule < 3.0. scenario.name was removed in later versions) In the molecule.yml file change the scenario.name attribute to uninstall.

• In the same file, use the default scenario's playbook.yml file as the playbook for the prepare step:

    provisioner:
      name: ansible
      playbooks:
        prepare: ../default/playbook.yml
        converge: playbook.yml
  

• Adjust the tests for the uninstall scenario to verify the uninstall steps.

This will ensure that the same steps are used for installing the software as in the install/default scenario, and you can focus on the uninstall steps.

To run the scenarios you can either run all of them or a single one:

# Run all scenarios
molecule test --all

# Run only the uninstall scenario
molecule test --scenario-name uninstall

This should get you pretty close to what you want to do, without replicating any code.

If you want to try some other things, here are a couple of other thoughts:

Alternatives

I would keep a scenario for the install only that would play all the needed tests (lint, idempotency, check, verify....) and create an install_uninstall specific scenario.

Playing install_uninstall will never be idempotent. So this scenario should disable the idempotency tests that will never pass. You might as well want to disable the check test that is played in your other scenario, lint... This can be done in molecule.yml by adjusting the parameters for scenario.test_sequence:

scenario:
  name: install_uninstall
  test_sequence:
    - destroy
    - create
    - prepare
    - converge
    - verify
    - destroy

Of course you can adjust to your real needs (like droping verify also if you have no testinfra tests for this case).

Once this is done you only have to add two plays in your scenario playbook:

---
- name: install
  hosts: all
  roles:
    - role: my_role
      install: true

- name: uninstall
  hosts: all
  roles:
    - role: my_role
      install: false

And you should be ready to test with:

molecule test -s install_uninstall

Edit:
An other option would be to keep only your current install scenario but launch the individual molecule commands rather than a full test. Assuming your current working scenario is in default

# Check and lint my files
molecule lint
# Make sure no box/container is on the way
molecule destroy
# Create my box/container for tests
molecule create
# Play my default playbook
molecule converge
# Idempotency check
molecule idempotence
# Verify we can correctly use check mode
molecule check
# Play testinfra tests
molecule verify
# Now play the uninstall
molecule converge -- -e install=false
## add more tests you can think off ##
# and finally cleanup
molecule destroy.

Unfortunately, unless this feature was very recently added to molecule, it is not possible to call idempotency and check with extra variables

Ansible yum module to install a list of packages AND remove any other packages

Building up on @gary lopez answer to add security and performance.

First you will need to get an actual list of all packages you want to see installed on your final machine, including the default ones that come with the system. I assume that list will be in var yum_rpm

Once you have that, the next step is to get the list of currently installed packages on the machine. To create an actual list we can reuse:

  - name: Get installed packages
    yum:
      list: installed
    register: __yum_packages

  - name: Make installed packages a list of names
    set_fact:
      installed_packages: "{{ __yum_packages.results | map(attribute='name') | list }}"

From there, adding and removing is just a matter of making a difference on lists. The goal here is to avoid looping on the yum module package by package (because it is damn slow and listed as a bad practice on the module documentation page) and to make the install and remove operations in one go.

  - name: align packages on system to expected
    yum:
      name: "{{ item.packages }}"
      state: "{{ item.state }}"
    loop:
      - packages: "{{ yum_rpm | difference(installed_packages) }}"
        state: present
      - packages: "{{ installed_packages | difference(yum_rpm) }}"
        state: absent
    when: item.packages | length > 0

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