ansible-playbook文件结构：

 1 ---
 2 - name: play1                       #指定的playbook名字 
 3   hosts: webservers                 #指定主机组
 4   remote_user: root                 #指定运行用户
 5   vars:                             #指定变量名
 6     var_name: value
 7   tasks:                            #指定要在playbook要做的那些事情
 8     - name: echo                    #指定输出的哪个阶段显示
 9       shell: "echo {{var_name}}"    #指定需要执行的命令
10  
11 - name: play2
12   hosts: webservers
13   remote_user: root
14   vars:
15     var_name: value
16   tasks:
17     - name: echo
18       shell: "echo {{var_name}}"
19       
20       
21  ---
22 - hosts: webservers
23   remote_user: root
24   vars:
25     var_name: value
26   tasks:
27     - name: echo
28       shell: "echo {{var_name}}"