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Installation of dependencies of an ansible role

Posted in automation on February 4, 2021 by Adrian Wyssmann ‐ 3 min read

ansible automation iac infrastructure-as-code

My ansible role papanito.ttrss is the first one using external dependencies i.e. roles made by others, as you can see in the meta/main.yml

....
dependencies:
  - role: geerlingguy.php
    vars:
      php_use_managed_ini: "{{ ttrss_php_use_managed_ini }}"
      ....
  - role: geerlingguy.postgresql
    vars:
      postgresql_restarted_state: "{{ ttrss_postgresql_restarted_state }}"
      ....

I was under the assumption that with this declaration in the meta/main.yml, dependencies would be installed automatically when using the role - apparently not. I have the following playbook for testing:

---
- hosts: localhost
  remote_user: root

  roles:
  - { role: ../ansible-role-ttrss }

However this fails, cause the respective dependencies are missing:

ansible-playbook tests/test.yml -i tests/inventory --syntax-chec
ERROR! the role 'geerlingguy.postgresql' was not found in ansible.legacy:/home/papanito/Workspaces/mydomain.com/ansible-role-ttrss/tests/roles:/home/papanito/.ansible/roles:/usr/share/ansible/roles:/etc/ansible/roles:/home/papanito/Workspaces/mydomain.com:/home/papanito/Workspaces/mydomain.com/ansible-role-ttrss/tests

The error appears to be in '/home/papanito/Workspaces/mydomain.com/ansible-role-ttrss/meta/main.yml': line 105, column 5, but may
be elsewhere in the file depending on the exact syntax problem.

The offending line appears to be:

      # php_source_configure_command: "{{ php_source_configure_command }}"
  - role: geerlingguy.postgresql
    ^ here

Looking at the documentation of ansible it says

Roles can also be dependent on other roles, and when you install a role that has dependencies, those dependencies will automatically be installed to the roles_path.

There are two ways to define the dependencies of a role:

  • using meta/requirements.yml
  • using meta/main.yml

Still this does not make it magically appear, the above only take place if you run ansible-galaxy install -r requirements.yml. So for your ansible project you define papanito.ttrss in the requirements.yml …

- src: https://github.com/papanito/ansible-role-ttrss.git
  name: papanito.ttrss
  scm: git
  version: master

… and then run ansible-galaxy install -r requirements.yml. Now we can see that the role papanito.ttrss and it’s dependencies are installed successfully.

ansible-galaxy install -r requirements.yml
Starting galaxy role install process
- extracting papanito.ttrss to /home/papanito/Workspaces/mydomain.com/infra/roles/papanito.ttrss
- papanito.ttrss (master) was installed successfully
- adding dependency: geerlingguy.php
- adding dependency: geerlingguy.postgresql
- downloading role 'php', owned by geerlingguy
- downloading role from https://github.com/geerlingguy/ansible-role-php/archive/4.5.1.tar.gz
- extracting geerlingguy.php to /home/papanito/Workspaces/mydomain.com/infra/roles/geerlingguy.php
- geerlingguy.php (4.5.1) was installed successfully
- downloading role 'postgresql', owned by geerlingguy
- downloading role from https://github.com/geerlingguy/ansible-role-postgresql/archive/3.0.0.tar.gz
- extracting geerlingguy.postgresql to /home/papanito/Workspaces/mydomain.com/infra/roles/geerlingguy.postgresql
- geerlingguy.postgresql (3.0.0) was installed successfully

So the issue with testing your own role - with dependencies - is that you also need a requirements.yml and run ansible-galaxy install -r requirements.yml to get the dependencies installed. Here my requirements.yml - so in addition to the declaration in meta/main.yml we also have to define the roles there:

roles:
- name: geerlingguy.postgresql
collections:
- name: geerlingguy.php_roles

Now ansible-playbook work as expected

$ ansible-galaxy install -r requirements.yml
Starting galaxy role install process
- downloading role 'postgresql', owned by geerlingguy
- downloading role from https://github.com/geerlingguy/ansible-role-postgresql/archive/3.0.0.tar.gz
- extracting geerlingguy.postgresql to /home/papanito/.ansible/roles/geerlingguy.postgresql
- geerlingguy.postgresql (3.0.0) was installed successfully
Starting galaxy collection install process
Process install dependency map
Starting collection install process
Installing 'geerlingguy.php_roles:1.0.0' to '/home/papanito/.ansible/collections/ansible_collections/geerlingguy/php_roles'
Downloading https://galaxy.ansible.com/download/geerlingguy-php_roles-1.0.0.tar.gz to /home/papanito/.ansible/tmp/ansible-local-1196058mmlqcy1v/tmp8fyay96j
geerlingguy.php_roles (1.0.0) was installed successfully

$ ansible-playbook tests/test.yml -i tests/inventory --syntax-check
  warnings.warn("urllib3 ({}) or chardet ({}) doesn't match a supported "

playbook: tests/test.yml
ansible automation iac infrastructure-as-code

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