fail模塊

想要playbook按照我們的意願中斷任務，可以借助fail模塊。

在任務沒有設置ignore_errors:true情況下，如果有任務執行失敗，playbook會自動停止執行，當fail模塊執行後，playbook會認為任務執行失敗了，會主動中止任務。

---
- hosts: all
  remote_user: root
  tasks:
  - debug:
      msg: "1"
  - debug:
      msg: "2"
  - fail:
  - debug:
      msg: "3"
  - debug:
      msg: "4"
 

我們也可以通過fail模塊自帶的msg，自定義報錯信息，

---
- hosts: test70
  remote_user: root
  tasks:
  - debug:
      msg: "1"
  - fail:
      msg: "Interrupt running playbook"
  - debug:
      msg: "2"

fail+when

fail模塊通常與when模塊結合，如果中斷劇本的條件成立，則執行fail模塊，中斷劇本。

---
- hosts: all
  remote_user: root
  tasks:
  - shell: "echo ‘This is a string for testing--error‘"
    register: return_value
  - fail:
      msg: "Conditions established,Interrupt running playbook"
    when: "‘error‘ in return_value.stdout"
  - debug:
      msg: "I never execute,Because the playbook has stopped"

failed_when也可以完成類似的功能，當條件成立時將對應任務的狀態設置為失敗，中止劇本。

---
- hosts: all
  remote_user: root
  tasks:
  - debug:
      msg: "I execute normally"
  - shell: "echo ‘This is a string for testing error‘"
    register: return_value
    failed_when: ‘ "error" in return_value.stdout‘
  - debug:
      msg: "I never execute,Because the playbook has stopped"

changed_when

failed_when關鍵詞的作用是在條件成立時將任務狀態改為失敗。

changed_when關鍵詞的作用是在條件成立時，將任務狀態改為changed。

---
- hosts: all
  remote_user: root
  tasks:
  - debug:
      msg: "test message"
    changed_when: 2 > 1

當changed_when狀態被設置為false時，不管原任務狀態為啥，最終都會被設置為ok狀態

---
- hosts: all
  remote_user: root
  tasks:
  - shell: "ls /opt"
    changed_when: True

Ansible-----條件判斷與錯誤處理