Error Handling and Debugging

Real-world automation must handle failures gracefully. Ansible provides several mechanisms for error handling, custom failure conditions, and debugging tools to help you troubleshoot issues.

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Default Error Behaviour

By default, when a task fails on a host:

1. Ansible stops executing further tasks on that host
2. Other hosts continue (unless any_errors_fatal: true is set)
3. Handlers that were notified are not run for the failed host

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ignore_errors

Continue execution even when a task fails:

tasks:
  - name: Check if legacy app exists
    command: which legacy-app
    register: legacy_check
    ignore_errors: true

  - name: Report legacy app status
    debug:
      msg: "Legacy app {{ 'found' if legacy_check.rc == 0 else 'not found' }}"

Warning: Use ignore_errors sparingly --- it suppresses all errors, which can mask real problems. Prefer failed_when for fine-grained control.

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ignore_unreachable

Continue when a host is unreachable (network issues, SSH failures):

tasks:
  - name: Attempt to gather info
    command: hostname
    ignore_unreachable: true

  - name: This still runs even if host was unreachable
    debug:
      msg: "Continuing..."

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failed_when

Define custom failure conditions: