ansible系列(24)--ansible的loop循环语句

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目录

• 1. loop循环语句
  • 1.1 使用循环批量安装软件
  • 1.2 使用循环批量启动服务
  • 1.3 使用循环批量创建用户
  • 1.4 使用循环批量拷贝文件

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1. loop循环语句

在写 playbook 的时候发现了很多 task 都要重复引用某个相同的模块，比如一次启动10个服务，或者一次拷贝10个文件，如果按照传统的写法最少要写10次，这样会显得 playbook 很臃肿。如果使用循环的方式来编写 playbook ，这样可以减少重复编写 task 带来的臃肿。

引用格式：

• 对迭代项的引用，固定变量名为"item"；
• 要在task中使用with_items或loop关键字给定要迭代的元素列表；

1.1 使用循环批量安装软件

• 方式一：

  [root@xuzhichao playbook]# cat loop_install.yml
  - hosts: NginxWebs
    remote_user: root
  
    tasks:
      - name: Install Packages
        yum:
          name: "{{ item }}"
          state: present
        loop:
          - httpd
          - mariadb-server
  

• 运行playbook：

  root@xuzhichao playbook]# ansible-playbook loop_install.yml 
  
  PLAY [NginxWebs] **********************************************************************************************************************************************
  
  TASK [Install Packages] ***************************************************************************************************************************************
  ok: [192.168.20.23] => (item=httpd)
  ok: [192.168.20.22] => (item=httpd)
  changed: [192.168.20.23] => (item=mariadb-server)
  changed: [192.168.20.22] => (item=mariadb-server)
  
  PLAY RECAP ****************************************************************************************************************************************************
  192.168.20.22              : ok=1    changed=1    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0
  192.168.20.23              : ok=1    changed=1    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0
  

• 方式二：

  [root@xuzhichao playbook]# cat loop_install1.yml
  - hosts: NginxWebs
    remote_user: root
    vars:
      packages:
        - httpd
        - mariadb-server
  
    tasks:
      - name: Install Packages
        yum:
          name: "{{ packages }}"
          state: present
  

• 运行playbook：

  [root@xuzhichao playbook]# ansible-playbook loop_install1.yml
  
  PLAY [NginxWebs] **********************************************************************************************************************************************
  
  TASK [Install Packages] ***************************************************************************************************************************************
  changed: [192.168.20.23]
  changed: [192.168.20.22]
  
  PLAY RECAP ****************************************************************************************************************************************************
  192.168.20.22              : ok=1    changed=1    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0
  192.168.20.23              : ok=1    changed=1    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0
  

1.2 使用循环批量启动服务

playbook文件如下：

[root@xuzhichao playbook]# cat loop_service.yml
- hosts: NginxWebs
  remote_user: root

  tasks:
    - name: Start Service
      service:
        name: "{{ item }}"
        state: started
      loop:
        - httpd
        - mariadb-server

运行playbook：

[root@xuzhichao playbook]# ansible-playbook -C loop_service.yml 

PLAY [NginxWebs] **********************************************************************************************************************************************

TASK [Start Service] ******************************************************************************************************************************************
changed: [192.168.20.23] => (item=httpd)
changed: [192.168.20.22] => (item=httpd)
changed: [192.168.20.23] => (item=mariadb-server)
changed: [192.168.20.22] => (item=mariadb-server)

PLAY RECAP ****************************************************************************************************************************************************
192.168.20.22              : ok=1    changed=1    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0
192.168.20.23              : ok=1    changed=1    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0

1.3 使用循环批量创建用户

批量创建用户，使用 key values 字典的方式。

[root@xuzhichao playbook]# cat loop_createuser.yml
- hosts: NginxWebs
  tasks:
    - name: Create Groups
      group:
        name: "{{ item }}"
        state: present
      loop:
          - group1
          - group2
          - group3

    - name: Create Users
      user:
        name: "{{ item.user }}"
        group: "{{ item.group }}"
        uid: "{{ item.uid }}"
        state: present
        create_home: yes
      loop:
        - { user: user1, group: group1, uid: 2001 }
        - { user: user2, group: group2, uid: 2002 }
        - { user: user3, group: group3, uid: 2003 }

运行playbook：

[root@xuzhichao playbook]# ansible-playbook -C loop_createuser.yml 

PLAY [NginxWebs] **********************************************************************************************************************************************

TASK [Create Groups] ******************************************************************************************************************************************
ok: [192.168.20.23] => (item=group1)
ok: [192.168.20.22] => (item=group1)
ok: [192.168.20.23] => (item=group2)
ok: [192.168.20.22] => (item=group2)
changed: [192.168.20.23] => (item=group3)
changed: [192.168.20.22] => (item=group3)

TASK [Create Users] *******************************************************************************************************************************************
changed: [192.168.20.22] => (item={u'group': u'group1', u'user': u'user1', u'uid': 2001})
changed: [192.168.20.23] => (item={u'group': u'group1', u'user': u'user1', u'uid': 2001})
changed: [192.168.20.22] => (item={u'group': u'group2', u'user': u'user2', u'uid': 2002})
changed: [192.168.20.23] => (item={u'group': u'group2', u'user': u'user2', u'uid': 2002})
changed: [192.168.20.23] => (item={u'group': u'group3', u'user': u'user3', u'uid': 2003})
changed: [192.168.20.22] => (item={u'group': u'group3', u'user': u'user3', u'uid': 2003})

PLAY RECAP ****************************************************************************************************************************************************
192.168.20.22              : ok=2    changed=2    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0
192.168.20.23              : ok=2    changed=2    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0

1.4 使用循环批量拷贝文件

在需要拷贝多个文件，这些文件又有不同的属主属组权限等属性时，而且拷贝到的目标目录不同时，可以使用循环来拷贝文件。

示例，playbook文件如下：

[root@xuzhichao playbook]# cat loop_copyfile.yml
- hosts: NginxWebs
  tasks:
    - name: Copy Configuer File
      template:
        src: "{{ item.src }}"
        dest: "{{ item.dest }}"
        owner: "{{ item.owner }}"
        group: "{{ item.group }}"
        omode: "{{ item.mode }}"
      loop:
        - { src: "conf/nginx.conf.j2", dest: "/etc/nginx/nginx.conf", owner: "root", group: "root", mode: "0644" }
        - { src: "conf/example.com.conf.j2", dest: "/etc/nginx/conf.d/example.con.conf", owner: "root", group: "root", mode: "0644" }
        - { src: "file/index.html", dest: "/data/nginx/example/index.html", owner: "nginx", group: "nginx", mode: 0644 }

创建相关模板文件：

[root@xuzhichao playbook]# touch conf/nginx.conf.j2
[root@xuzhichao playbook]# touch conf/example.com.conf.j2
[root@xuzhichao playbook]# touch file/index.html

运行playbook：

[root@xuzhichao playbook]# ansible-playbook -C loop_copyfile.yml 

PLAY [NginxWebs] ****************************************************************************************************************************

TASK [Copy Configuer File] *****************************************************************************************************************************
changed: [192.168.20.23] => (item={u'dest': u'/etc/nginx/nginx.conf', u'src': u'conf/nginx.conf.j2', u'group': u'root', u'mode': u'0644', u'owner': u'root'})
changed: [192.168.20.22] => (item={u'dest': u'/etc/nginx/nginx.conf', u'src': u'conf/nginx.conf.j2', u'group': u'root', u'mode': u'0644', u'owner': u'root'})
changed: [192.168.20.22] => (item={u'dest': u'/etc/nginx/conf.d/example.con.conf', u'src': u'conf/example.com.conf.j2', u'group': u'root', u'mode': u'0644', u'owner': u'root'})
changed: [192.168.20.23] => (item={u'dest': u'/etc/nginx/conf.d/example.con.conf', u'src': u'conf/example.com.conf.j2', u'group': u'root', u'mode': u'0644', u'owner': u'root'})
changed: [192.168.20.23] => (item={u'dest': u'/data/nginx/example/index.html', u'src': u'file/index.html', u'group': u'nginx', u'mode': 420, u'owner': u'nginx'})
changed: [192.168.20.22] => (item={u'dest': u'/data/nginx/example/index.html', u'src': u'file/index.html', u'group': u'nginx', u'mode': 420, u'owner': u'nginx'})