ansible-playbook流程控制-when条件判断

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1. ansible-playbook添加判断
when相当于shell脚本里的if 判断，when语句就是用来实现这个功能的，它是一个jinja2的语法，但是不需要双大括号，用法很简单
1.1) 示例1：

1 [root@test-1 when]# vim when_test1.yaml
2 [root@test-1 when]# cat when_test1.yaml
3 ---
4 - hosts: web1
5 gather_facts: yes
6
7 tasks:
8 - name: "IP if"
9 debug: msg={{ansible_default_ipv4.address}}
10 when: ansible_default_ipv4.address == '192.168.200.133'
11
12 # 注意 Ansible facts和vars 比如 ansible_os_family 应能被引用
13 # 直接写，不带双大括号。

1.2) 示例2：使用括号对条件进行分组

1 [root@test-1 when]# vim when_test2.yaml
2 [root@test-1 when]# cat when_test2.yaml
3 ---
4 - hosts: localhost
5 gather_facts: yes
6
7 tasks:
8 - name: "shut down CentOS 6 and Debian 7 systems"
9 command: ls -a
10 when: (ansible_facts['distribution'] == "CentOS" and ansible_facts['distribution_major_version'] == "6") or
11 (ansible_facts['distribution'] == "Debian" and ansible_facts['distribution_major_version'] == "7")

1.3) 示例3：所有需要为true的多条件判读（逻辑“and”）也可以指定为列表

1 [root@test-1 when]# vim when_test3.yaml
2 [root@test-1 when]# cat when_test3.yaml
3 ---
4 - hosts: localhost
5 gather_facts: yes
6
7 tasks:
8 - name: "shut down CentOS 7 systems"
9 command: ls -a
10 when:
11 - ansible_facts['distribution'] == "CentOS"
12 - ansible_facts['distribution_major_version'] == "7"

2. 案例：
2.1) ansible-playbook进行when判断是centos还是Ubuntu系统后在安装http

1 [root@test-1 when]# vim when_mc.yaml
2 [root@test-1 when]# cat when_mc.yaml
3 ---
4 - hosts: localhost
5 gather_facts: yes
6
7 tasks:
8 - name: "update apache version - yum"
9 yum: name=httpd state=present
10 when:
11 - ansible_pkg_mgr == 'yum'
12 notify: restart httpd
13
14 - name: "Update apache version - apt"
15 apt: name=apache2 state=present update_cache=yes
16 when:
17 - ansible_pkg_mgr == 'apt'
18 notify: restart apache2
19
20
21 handlers:
22 - name: restart apache2
23 service: name=apache2 state=restarted
24 - name: restart httpd
25 service: name=httpd state=restarted

2.2) 配置文件检查

1 [root@test-1 when]# ansible-playbook --syntax-check when_mc.yaml
2
3 playbook: when_mc.yaml

2.3) 执行远程安装脚本

1 [root@test-1 when]# ansible-playbook when_mc.yaml
2
3 PLAY [localhost] *******************************************************************************************************************************
4
5 TASK [Gathering Facts] *************************************************************************************************************************
6 ok: [192.168.200.131]
7
8 TASK [update apache version - yum] *************************************************************************************************************
9 changed: [192.168.200.131]
10
11 TASK [Update apache version - apt] *************************************************************************************************************
12 skipping: [192.168.200.131]
13
14 RUNNING HANDLER [restart httpd] ****************************************************************************************************************
15 changed: [192.168.200.131]
16
17 PLAY RECAP *************************************************************************************************************************************
18 192.168.200.131 : ok=3 changed=2 unreachable=0 failed=0 skipped=1 rescued=0 ignored=0