仅在需要升级时停止服务的 Ansible 方法

Question

在 ansible playbook 中，如果需要升级，我想停止 MariaDB(在我的情况下，从 RPM 包重新启动并不总是有效)。我对ansible很陌生。

我想出了这个:

- name: "Check if MariaDB needs to be upgraded"
  shell: "yum check-update MariaDB-server|grep MariaDB|wc -l"
  register: needs_update

- name: "Stop mysql service"
  service:
  name: mysql
  state: stopped
when: needs_update.stdout == "1"

有没有比执行 shell 命令更好的方法呢？运行它时，我收到警告:

TASK [mariadb_galera : Check if MariaDB needs to be upgraded]    ******************
changed: [139.162.220.42] => {"changed": true, "cmd": "yum check-update MariaDB-server|grep MariaDB|wc -l", "delta": "0:00:00.540862", "end": "2017-03-01 13:03:34.415272", "rc": 0, "start": "2017-03-01 13:03:33.874410", "stderr": "", "stdout": "0", "stdout_lines": ["0"], "warnings": ["Consider using yum module rather than running yum"]}
 [WARNING]: Consider using yum module rather than running yum

谢谢!

Answer 1

您可以通过以下方式隐藏警告:

- name: "Check if MariaDB needs to be upgraded"
  shell: "yum check-update MariaDB-server|grep MariaDB|wc -l"
  args:
    warn: false
  register: needs_update

或者你可以欺骗 Ansible 执行 yum任务在 check_mode :

- name: "Check if MariaDB needs to be upgraded (CHECK MODE!)"
  yum:
    name: MariaDB-server
    state: latest
  check_mode: yes
  register: needs_update_check

- name: "Stop mysql service"
  service:
    name: mysql
    state: stopped
  when: needs_update_check | changed

请在使用前测试此代码。