Ansible Idempotency Patterns

Techniques for ensuring Ansible tasks are truly idempotent - producing the same result whether run once or multiple times.

Core Directives

changed_when

Controls when Ansible reports a task as "changed". Critical for command and shell modules which always report changed by default.

- name: Check if service exists
  ansible.builtin.command: systemctl status myservice
  register: service_check
  changed_when: false  # Read-only operation, never changes anything