Grouping tasks with blocks

Ansible playbook that demonstrates the use of blocks, along with rescue and always sections.

---
- name: Attempt and Graceful Rollback Demo
  hosts: all
  tasks:
    - name: Print a message
      ansible.builtin.debug:
        msg: 'I execute normally'
      # This task prints a message indicating normal execution.

    - name: Force a failure
      ansible.builtin.command: /bin/false
      # This task intentionally fails by executing a non-existent command.

    - name: Never print this
      ansible.builtin.debug:
        msg: 'I never execute, due to the above task failing, :-('
      # This task will not execute because the previous task failed.

  rescue:
    - name: Print when errors
      ansible.builtin.debug:
        msg: 'I caught an error'
      # In case of an error, this task prints a message.

    - name: Force a failure in middle of recovery! >:-)
      ansible.builtin.command: /bin/false
      # This task intentionally fails during the recovery phase.

    - name: Never print this
      ansible.builtin.debug:
        msg: 'I also never execute :-('
      # This task will not execute due to the previous task failing.

  always:
    - name: Always do this
      ansible.builtin.debug:
        msg: "This always executes"
      # Regardless of success or failure, this task always runs.

Explanation:

1. Print a message:

   • This task prints a message indicating normal execution.

   • It will execute unless there's a catastrophic failure before this task.

2. Force a failure:

   • This task intentionally fails by executing a non-existent command (/bin/false).

   • Since it fails, the subsequent task in the same block won't execute.

3. Never print this:

   • This task will not execute because the previous task failed.

   • It's part of the same block as the failed task.

4. Rescue section:

   • If any task in the block fails, the rescue section is triggered.

   • Print when errors task will execute and print a message.

5. Force a failure in middle of recovery! >:-):

   • This task intentionally fails during the recovery phase.

   • It's part of the rescue section.

6. Never print this (rescue section):

   • This task will not execute due to the previous task failing.

   • It's also part of the rescue section.

7. Always section:

   • Regardless of success or failure, this section always runs.

   • The Always do this task prints a message.

This example is directly copy pasted from the Ansible documentation.