ansible when

Ansible中的when语句用于在任务执行之前判断条件是否成立，只有条件成立时才会执行任务。when语句可以使用逻辑运算符and、or和not来组合多个条件，也可以使用括号来改变条件的优先级。以下是几个when语句的示例：

1. 逻辑与

when: ansible_distribution == "CentOS" and ansible_distribution_major_version == "7"

2. 逻辑或

when: ansible_distribution == "RedHat" or ansible_distribution == "Fedora"

3. 组合使用

when: ( ansible_distribution == "RedHat" and ansible_distribution_major_version == "7" ) or ( ansible_distribution == "Fedora" and ansible_distribution_major_version == "28" )

4. not运算符

when: not ansible_distribution == "Ubuntu"