Ansible - multiple roles

Question

I am trying to run multiple roles using with_items command, however I am getting error:

"ERROR! 'item' is undefined"

role.yml:

---
- hosts: '{{ host }}'
  become: yes

  roles:
    - role: "{{item}}"
      with_items: "{{ roles }}"

Here is my command:

ansible-playbook -i ./inventory/Dev ./playbooks/role.yml --extra-vars='{"host": "db", "roles": ["mysql", "apache"]}'

Answer 1

You cannot do it this way. with_ loops are not valid for roles.

^{If anything, you need to provide a list of roles to the roles: directive, so the syntax would be just like for the list of host groups hosts: '{{ host }}'. The problem is: Ansible does not resolve the variable for roles, so roles: '{{ roles }}' does not work.}

---

What you can do, however, is to use include_role module in which you can access the variables.

^{No, include_role module doesn't take {{ item }} from the with_items as a value for name either.}

So the only workaround I can think of (assuming you don't want to process the JSON beforehand) is to the include the roles statically:

tasks:
  - include_role:
      name: "mysql"
    when: "'mysql' in roles"
  - include_role:
      name: "apache"
    when: "'apache' in roles"

The roles need to exist on the control machine anyway, so all their names are predefined.