Ansible角色：实现应用启动重试与成功跳转运行逻辑

需求说明 #

• 启动应用最多重试3次，成功返回"OK"，失败返回"NOK"
• 每次启动失败（输出"NOK"）时，必须删除xpto目录，最多尝试3次，3次失败则终止执行
• 启动成功（输出"OK"）则跳过目录删除，直接运行应用
• 角色仅包含启动应用、删除目录、运行应用三个核心任务

现有代码（缺少重试与跳转逻辑） #

---    
- name: Start app
  command: start app
  register: result
  tags: myrole

- name: Delete directory xpto if app didn't started ok
  command: rm -rf xpto
  when:
    - result.stdout is search("NOK")
  tags: myrole

- name: Run the application
  command: app run xpto
  when:
    - result.stdout is search("OK")
  tags: myrole

解决方案代码 #

以下实现完全满足需求，通过循环重试、状态标记实现每次失败后的目录清理，成功后直接跳转至运行应用任务：

---
- name: Initialize start success flag
  set_fact:
    start_success: false
  tags: myrole

- name: Attempt to start app with retries (max 3 times)
  block:
    - name: Start app
      command: start app
      register: start_result
      tags: myrole

    - name: Mark start as successful if output is "OK"
      set_fact:
        start_success: true
      when: start_result.stdout is search("OK")
      tags: myrole

    - name: Delete xpto directory on start failure
      command: rm -rf xpto
      when: start_result.stdout is search("NOK")
      tags: myrole
  # 重试终止条件：启动成功 或 已尝试3次
  until: start_success or ansible_loop.index == 3
  retries: 3
  delay: 2  # 可选，每次重试间隔2秒，可按需调整
  loop: "{{ range(3) | list }}"
  loop_control:
    extended: true
    loop_var: dummy
  tags: myrole

- name: Run the application if start succeeded
  command: app run xpto
  when: start_success
  tags: myrole

- name: Terminate execution if all attempts failed
  fail:
    msg: "Failed to start application after 3 attempts"
  when: not start_success
  tags: myrole

逻辑说明 #

1. 状态初始化：用start_success变量记录启动状态，初始值为false
2. 循环重试流程：通过block包裹三个核心任务，循环执行最多3次：
   • 启动应用后检查输出，若为"OK"则标记启动成功，终止循环
   • 若输出为"NOK"，立即删除xpto目录，然后进入下一次重试
3. 最终分支处理：
   • 启动成功则直接执行运行应用任务
   • 3次尝试均失败时，触发fail任务终止执行

内容的提问来源于stack exchange，提问作者fr0zt