# ansible playbook 详解

ansible playbook 能将ansible的任务执行分解成各个部分，使远程配置更加强大和灵活。

**核心组件**

* Tasks：任务，由模板定义的操作列表
* Variables：变量
* Templates：模板，即使用模板语法的文件
* Handlers：处理器 ，当某条件满足时，触发执行的操作
* Roles：角色

**yaml中的字段**

* hosts ：指定主机组，（，分隔多个）
* remote\_user ：使用的用户
* gather\_facts ：是否收集主机的信息
* vars ：自定义的变量
* tasks ：任务组
  * name ：任务名
  * module ：执行的模块
  * notify ：任务状态变触发的handlers
  * with\_items ：循环处理
  * when ：条件判断
* handlers ：处理器

```yaml
--- 

- hosts: testhost
  user: root
  gather_facts: false
  tags: 
    - always      # 指定tags，可是使用 ansible-playbook -t always 执行标记了的task
  vars:
    name: "test"
    service: "nginx"
    exist: "True"

  tasks:
    - name: change mode for files
      file: path=/tmp/{{ item }} mode=600
      # {{ var }} 可以是/etc/ansible/hosts中的，gather中的，vars中的
      template: src=. dest=. # 指定模板
      with_items:
        - 1.txt
        - 2.txt
        - 3.txt

    - name: installed nginx
      yum: name="{{ service }}" 
      when: ansible_ens33.ipv4.address == "172.7.15.114"   # ansible <host> -m setup 可以查看到所有的gather信息

      when: exist | match("True")                          # 支持 () , and, or, 自定义条件   
    - name: create file
      file: path=/tmp/123 state=touch
      notify: test handler

   handlers:
     - name: test handler
       shell: echo "123" > /tmp/11.txt
```

```yaml
---
- hosts: 192.168.127.129
  remote_user: root
  tasks:
    - name: test_playbook
      shell: touch /tmp/test.txt
    - name: task2
      shell: touch /tmp/tasks2.txt
```

```yaml
# 循环实例
---
- hosts: testhost
  user: root
  tasks:
    - name: change mode for files
      file: path=/tmp/{{ item }} state=touch mode=600
      with_items:
        - 1.txt
        - 2.txt
        - 3.txt
```

```bash
# ansible-playbook test.yml --syntax-check # 验证yaml文件语法格式

playbook: test.yml
```

```yaml
# 条件实例
---
- hosts: testhost
  user: root
  gather_facts: True
  tasks:
    - name: use when
      shell: touch /tmp/when.txt
      when: ansible_ens33.ipv4.address == "172.7.15.114"
      # ansible aming-02 -m setup 可以查看到所有的facter信息
```

```yaml
# handlers 实例
---
- name: handlers test
  hosts: 192.168.127.129
  user: root
  tasks:
    - name: copy file
      copy: src=/etc/passwd dest=/tmp/aaa.txt
      notify: test handlers

  handlers:
    - name: test handlers
      shell: echo "111111" >> /tmp/aaa.txt
```


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