ansible-error-handling

Ansible Error Handling

Patterns for robust error handling in Ansible playbooks and roles.

Block/Rescue/Always Pattern

Handle errors and perform cleanup:

- name: Deploy application
  block:
    - name: Stop application
      ansible.builtin.systemd:
        name: myapp
        state: stopped

    - name: Deploy new version
      ansible.builtin.copy:
        src: myapp-v2.0
        dest: /usr/bin/myapp

    - name: Start application
      ansible.builtin.systemd:
        name: myapp
        state: started

  rescue:
    - name: Rollback to previous version
      ansible.builtin.copy:
        src: myapp-backup
        dest: /usr/bin/myapp

    - name: Start application (rollback)
      ansible.builtin.systemd:
        name: myapp
        state: started

    - name: Report failure
      ansible.builtin.fail:
        msg: "Deployment failed, rolled back to previous version"

  always:
    - name: Cleanup temp files
      ansible.builtin.file:
        path: /tmp/deploy-*
        state: absent

Execution Flow

• block: Main tasks execute sequentially
• rescue: Runs if ANY task in block fails
• always: Runs regardless of success/failure

Retry with Until

Handle transient failures with retries:

- name: Wait for service to be ready
  ansible.builtin.uri:
    url: http://localhost:8080/health
    status_code: 200
  register: health_check
  until: health_check.status == 200
  retries: 30
  delay: 10
  # Total wait: up to 5 minutes (30 * 10s)

With Command Module

- name: Wait for cluster to stabilize
  ansible.builtin.command: pvecm status
  register: cluster_status
  until: "'Quorate: Yes' in cluster_status.stdout"
  retries: 12
  delay: 5
  changed_when: false

Retry Parameters

Parameter	Description
until	Condition that must be true to stop retrying
retries	Maximum number of attempts
delay	Seconds between attempts

Assert for Validation

Validate inputs with clear error messages: