# playbook.yml
---
# header stuff
  vars:
    update: true
  tasks:
    - include: mysqldump.yml

# mysqldump.yml
---
- name: Update when {{ update }}
  block:
    - name: Dump all databases to hostname
      mysql_db:
        state: dump
        name: "{{ dbname }}"
        target: "/tmp/{{ dbname }}-{{ inventory_hostname }}.sql"
        login_user: "{{ mysql_user_name }}"
        login_password: "{{ mysql_user_password }}"
        login_newhost: "{{ dbhost }}"
  when: update