include plays in ansible playbook

install_wiki.yml

---
# You can't include plays in plays
# This will FAIL a syntax check / will not execute
- hosts: mw_hosts
  name: Install sources, extensions and skins
  tasks:
    - name: Do Nothing At All
      debug: msg="I'm a task"
    - include: install_mediawiki.yml
    - include: install_extensions.yml
    - include: install_skins.yml
# instead, either call ansible-playbook install_wiki.yml install_mediawiki.yml install_extensions.yml ...
# OR, move the includes to the level of an independent play
# This WILL work
- hosts: mw_hosts
  name: Install sources, extensions and skins
  tasks:
    - name: Do Nothing At All
      debug: msg="I'm a task"
- include: install_mediawiki.yml
- include: install_extensions.yml
- include: install_skins.yml