Ansible-----条件判断与错误处理

Posted 2021-02-15 jinyuanliu

 

 

 

 

 

 

 

 

fail模块

想要playbook按照我们的意愿中断任务，可以借助fail模块。

在任务没有设置ignore_errors:true情况下，如果有任务执行失败，playbook会自动停止执行，当fail模块执行后，playbook会认为任务执行失败了，会主动中止任务。

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

我们也可以通过fail模块自带的msg，自定义报错信息，

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

fail+when

 fail模块通常与when模块结合，如果中断剧本的条件成立，则执行fail模块，中断剧本。

---
- 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也可以完成类似的功能，当条件成立时将对应任务的状态设置为失败，中止剧本。

---
- 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关键词的作用是在条件成立时将任务状态改为失败。

changed_when关键词的作用是在条件成立时，将任务状态改为changed。

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

 当changed_when状态被设置为false时，不管原任务状态为啥，最终都会被设置为ok状态

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