when条件语句

when判断在Ansible中的使用频率非常高；比如yum模块可以自动检测软件包是否已被安装，而无需人为干涉，但对于有些任务则是需要进行判断才可以实现的。

• 比如：web节点都需要配置nginx仓库，但其他节点并不需要，此时就会用到when判断。
• 比如:Centos与Ubuntu都需要安装Apache，而Centos系统软件包为httpd，而Ubuntu系统软件包为httpd2，那么此时就需要判断主机系统，然后为不同的主机系统安装不同的软件包。

案例1-根据不同操作系统安装相同的软件

1. 为所有主机安装Apache软件

   • 系统为CentOS：安装httpd
   • 系统为Ubuntu：安装httpd2

   [root@manager control]# cat when_system.yml
   - hosts: webservers
     tasks:
       #通过fact变量判断系统为centos才会安装httpd
       - name: Centos Install httpd
         yum: name=httpd state=present
         when: (ansible_distribution == "CentOS")
   
       #通过fact变量判断系统为ubuntu才会安装httpd2
       - name: Ubuntu Install httpd
         yum: name=httpd2 state=present
         when: (ansible_distribution == "Ubuntu")
   

2. 执行playbook

   [root@manager control]# ansible-playbook when_system.yml
   
   PLAY [webservers] ********************************************************************
   
   TASK [Centos Install httpd] **********************************************************
   ok: [10.0.0.13]
   ok: [10.0.0.12]
   
   TASK [Ubuntu Install httpd] **********************************************************
   skipping: [10.0.0.12]
   skipping: [10.0.0.13]
   
   PLAY RECAP ***************************************************************************
   10.0.0.12                  : ok=1    changed=0    unreachable=0    failed=0    skipped=1    rescued=0    ignored=0
   10.0.0.13                  : ok=1    changed=0    unreachable=0    failed=0    skipped=1    rescued=0    ignored=0
   

案例2-为特定的主机添加Nginx仓库

1. 为所有主机添加Nginx仓库

   • 主机名为web：添加Nginx仓库
   • 主机名不为web：不做任何处理

   [root@manager control]# cat when_yum.yml
   - hosts: all
     tasks:
       - name: Add Nginx Yum Repository
         yum_repository:
           name: nginx
           description: Nginx Repository
           baseurl: http://nginx.org/packages/centos/7/$basearch/
           gpgcheck: no
         when: (ansible_hostname is match("web"))
   
   # 当然when也可以使用and与or方式
   # when: (ansible_hostname is match("web*")) or (ansible_hostname is match("lb*"))
   
   

2. 执行playbook

   [root@manager control]# ansible-playbook when_yum.yml
   

### 案例3-判断服务是否正常运行

- 判断`httpd`服务是否处于运行状态
    - 已运行：则重启服务
    - 未运行：则不做处理

1. 通过`register`将命令执行结果保存至变量，然后通过`when`语句进行判断

    ```sh
    [root@manager control]# cat when_service.yml
    - hosts: webservers
      tasks:
        - name: Check Httpd Server
          command: systemctl is-active httpd
          ignore_errors: yes
          register: check_httpd

        - name: debug outprint #通过debug的var输出该变量的所有内容
          debug: var=check_httpd

        - name: Httpd Restart #如果check_httpd执行命令结果等于0，则执行重启httpd，否则跳过
          service: name=httpd state=restarted
          when: check_httpd.rc == 0

    ```

2. 执行`playbook`

    ```sh
    [root@manager control]# ansible-playbook when_service.yml
    PLAY [webservers] ********************************************************************
    TASK [Check Httpd Server] ************************************************************
        changed: [10.0.0.13]
        changed: [10.0.0.12]

    TASK [debug outprint] ****************************************************************
        ok: [10.0.0.12] => {
            "check_httpd": {
                "changed": true,
                "cmd": [
                    "systemctl",
                    "is-active",
                    "httpd"
                ],
                "delta": "0:00:00.005817",
            "end": "2022-03-28 07:18:35.245988",
                "failed": false,
                "rc": 0,
                "start": "2022-03-28 07:18:35.240171",
            "stderr": "",
                "stderr_lines": [],
                "stdout": "active",
                "stdout_lines": [
                    "active"
                ]
            }
        }
        ok: [10.0.0.13] => {
            "check_httpd": {
                "changed": true,
                "cmd": [
                    "systemctl",
                    "is-active",
                    "httpd"
                ],
                "delta": "0:00:00.005770",
                "end": "2022-03-28 07:18:29.502212",
                "failed": false,
                "rc": 0,
                "start": "2022-03-28 07:18:29.496442",
                "stderr": "",
                "stderr_lines": [],
                "stdout": "active",
                "stdout_lines": [
                    "active"
                ]
            }
        }
    TASK [Httpd Restart] *****************************************************************
    changed: [10.0.0.12]
    changed: [10.0.0.13]

    PLAY RECAP ***************************************************************************
    10.0.0.12                  : ok=3    changed=2    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0
    10.0.0.13                  : ok=3    changed=2    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0

    ```



## 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；

### 案例1-使用循环批量启动服务

1. 在没有使用循环的场景下，启动多个服务需要写多条`task`任务。

    ```sh
    [root@manager control]# cat loop_service.yml
    - hosts: webservers
      tasks:
        - name: Installed Httpd Mariadb Package
          yum: name=httpd,mariadb state=latest

        - name: Start Httpd Server
          service: name=httpd state=started enabled=yes

        - name: Start Mariadb Server
          service: name=mariadb state=started enabled=yes
    ```

2. 我们将如上的`playbook`修改为循环的方式，减少重复编写多条`task`任务。

    ```sh
    [root@manager control]# cat loop_service.yml
    - hosts: webservers
      tasks:
        - name: Installed Httpd Mariadb Package
          yum: name=httpd,mariadb-server state=latest

        - name: Start Httpd Mariadb Server
          service: name={{ item }} state=started enabled=yes
          loop:
          - httpd
          - mariadb
    ```

3. 执行`playbook`

    ```sh
    [root@manager control]# ansible-playbook loop_service.yml
    PLAY [webservers] ********************************************************************

    TASK [Installed Httpd Mariadb Package] ***********************************************
        changed: [10.0.0.12]
        changed: [10.0.0.13]

    TASK [Start Httpd Mariadb Server] ****************************************************
        ok: [10.0.0.13] => (item=httpd)
        ok: [10.0.0.12] => (item=httpd)
        changed: [10.0.0.13] => (item=mariadb)
    changed: [10.0.0.12] => (item=mariadb)

    PLAY RECAP ***************************************************************************
    10.0.0.12                  : ok=2    changed=2    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0
    10.0.0.13                  : ok=2    changed=2    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0
    ```



### 案例2-使用循环批量安装软件

1. 批量安装软件

    ```sh
    [root@manager control]# cat loop_service_v2.yml
    - hosts: webservers
      tasks:
        - name: Installed Httpd Mariadb Package
          yum: name={{ pack }} state=latest
          vars:
            pack:
            - httpd
            - mariadb-server
    ```

2. 执行`playbook`

    ```sh
    [root@manager control]# ansible-playbook loop_service_v2.yml
    PLAY [webservers] ********************************************************************

    TASK [Installed Httpd Mariadb Package] ***********************************************
        ok: [10.0.0.12]
        ok: [10.0.0.13]

    PLAY RECAP ***************************************************************************
        10.0.0.12                  : ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0
        10.0.0.13                  : ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0
    ```



### 案例3-使用循环批量创建用户

1. 批量创建用户，使用`key values`字典的方式

    ```sh
    [root@manager control]# cat loop_user.yml
    - hosts: webservers
      tasks:
        - name: Add Users
          user: name={{ item.name }} groups={{ item.groups }} state=present
          with_items:
            - { name: "testuser1", groups: "bin" }
            - { name: "testuser2", groups: "root" }
    ```

2. 执行`playbook`

    ```sh
    [root@manager control]# ansible-playbook loop_user.yml
    PLAY [webservers] ********************************************************************

    TASK [Add Users] *********************************************************************
            changed: [10.0.0.13] => (item={u'name': u'testuser1', u'groups': u'bin'})
            changed: [10.0.0.12] => (item={u'name': u'testuser1', u'groups': u'bin'})
            changed: [10.0.0.12] => (item={u'name': u'testuser2', u'groups': u'root'})
        changed: [10.0.0.13] => (item={u'name': u'testuser2', u'groups': u'root'})

    PLAY RECAP ***************************************************************************
        10.0.0.12                  : ok=1    changed=1    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0
        10.0.0.13                  : ok=1    changed=1    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0

    ```



### 案例4-使用循环批量拷贝文件

```sh
[root@manager control]# cat loop_file.yml
- hosts: all
  tasks:
    - name: Configure Rsync Server
      copy: src={{ item.src }} dest=/etc/{{ item.dest }} mode={{item.mode }}

      with_items:
        - {src: "rsyncd.conf", dest: "rsyncd.conf", mode: "0644"}
        - {src: "rsync.passwd", dest: "rsync.passwd", mode: "0600"}

Handlers与Notify

Handlers是一个触发器，同时是一个特殊的tasks，它无法直接运行，它需要被tasks通知后才会运行。比如：httpd服务配置文件发生变更，我们则可通过Notify通知给指定的handlers触发器，然后执行相应重启服务的操作，如果配置文件不发生变更操作，则不会触发Handlers任务的执行；

案例-变更服务配置触发重启

1. 使用Ansible的playbook部署httpd服务

   [root@manager control]# cat webserver.yml
   - hosts: webservers
     remote_user: root
     #1.定义变量，在配置文件中调用
     vars:
       http_port: 8881
   
     tasks:
       #2.安装httpd服务
       - name: Install Httpd Server
         yum: name=httpd state=present
   
       #3.使用template模板，引用上面vars定义的变量至配置文件中
       - name: Configure Httpd Server
         template: src=./httpd.conf.j2 dest=/etc/httpd/conf/httpd.conf
         notify: #调用名称为Restart Httpd Server的handlers(可以写多个)
           - Restart Httpd Server
   
       #4.启动Httpd服务
       - name: Start Httpd Server
         service: name=httpd state=started enabled=yes
   
     #5.如果配置文件发生变化会调用该handlers下面的对应名称的task
     handlers:
       - name: Restart Httpd Server
         service: name=httpd state=restarted
   

2. 只有当我们修改配置文件才会触发handlers

   [root@manager control]# ansible-playbook webserver.yml
   PLAY [webservers] ********************************************************************
   
   TASK [Install Httpd Server] **********************************************************
           ok: [10.0.0.12]
           ok: [10.0.0.13]
   
   TASK [Configure Httpd Server] ********************************************************
           changed: [10.0.0.12]
           changed: [10.0.0.13]
   
   TASK [Start Httpd Server] ************************************************************
           ok: [10.0.0.12]
           ok: [10.0.0.13]
   
   RUNNING HANDLER [Restart Httpd Server] ***********************************************
           changed: [10.0.0.13]
           changed: [10.0.0.12]
   
   PLAY RECAP ***************************************************************************
           10.0.0.12                  : ok=4    changed=2    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0
           10.0.0.13                  : ok=4    changed=2    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0
   

Handlers注意事项与说明

• handlers注意事项
  • 无论多少个task通知了相同的handlers，handlers仅会在所有tasks结束后运行一次。
  • 只有task发生改变了才会通知handlers，没有改变则不会触发handlers。
  • 不能使用handlers替代tasks、因为handlers是一个特殊的tasks。

tags 任务标签

默认情况下，Ansible在执行一个playbook时，会执行playbook中所有的任务。而标签功能是用来指定要运行playbook中的某个特定的任务；

• 为playbook添加标签的方式有如下几种：
  • 对一个task打一个标签
  • 对一个task打多个标签
  • 对多个task打一个标签
• task打完标签使用的几种方式
  • -t执行指定tag标签对应的任务
  • --skip-tags执行除--skip-tags标签之外的所有任务

案例1-指定执行某个tags

1. 使用-t执行指定的tags标签对应的任务

   [root@manager control]# cat nfs.yml
   - hosts: nfs
     remote_user: root
     tasks:
       - name: Install Nfs Server
         yum: name=nfs-utils state=present
         tags:
           - install_nfs
           - install_nfs-server
   
       - name: Service Nfs Server
         service: name=nfs-server state=started enabled=yes
         tags: start_nfs-server
   
   

2. 执行playbook

   [root@manager control]# ansible-playbook nfs.yml
   PLAY [nfs] ***************************************************************************
   
   TASK [Install Nfs Server] ************************************************************
           ok: [10.0.0.12]
   
   TASK [Service Nfs Server] ************************************************************
           changed: [10.0.0.12]
   
   PLAY RECAP ***************************************************************************
           10.0.0.12                  : ok=2    changed=1    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0
   
   

3. 使用-t指定tags标签对应的任务， 多个tags使用逗号隔开即可

   [root@manager control]# ansible-playbook -t install_nfs-server nfs.yml
   PLAY [nfs] ***************************************************************************
   
   TASK [Install Nfs Server] ************************************************************
           ok: [10.0.0.12]
   
   PLAY RECAP ***************************************************************************
           10.0.0.12                  : ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0
   
   

案例2-指定排除某个tags

• 使用--skip-tags排除不执行的tags

  [root@manager control]# ansible-playbook --skip-tags install_nfs-server nfs.yml
  PLAY [nfs] ***************************************************************************
  
  TASK [Service Nfs Server] ************************************************************
      ok: [10.0.0.12]
  
  PLAY RECAP ***************************************************************************
  10.0.0.12                  : ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0
  
  

include任务复用

有时，我们发现大量的Playbook内容需要重复编写，各Tasks之间功能需相互调用才能完成各自功能，Playbook庞大到维护困难，这时我们需要使用include。比如：A项目需要用到重启httpd，B项目也需要用到重启httpd，那么我们可以使用Include来减少重复编写。

案例1-多个项目调用相同task

1. 编写restart_httpd.yml文件

   #注意这是一个tasks所以没有play的任何信息
   [root@manager control]# cat restart_httpd.yml
   - name: Restart Httpd Server
     service: name=httpd state=restarted
   

2. A Project的playbook如下

   [root@manager control]# cat a_project.yml
   - hosts: webservers
     tasks:
       - name: A Project command
         command: echo "A"
   
       - name: Restart httpd
         include: restart_httpd.yml
   
   

3. B Project的playbook如下

   [root@manager control]# cat b_project.yml
   - hosts: webservers
     tasks:
       - name: B Project command
         command: echo "B"
   
       - name: Restart httpd
         include: restart_httpd.yml
   

4. A Project和B Project执行后的测试结果如下

   [root@manager control]# ansible-playbook a_project.yml
   PLAY [webservers] ********************************************************************
   
   TASK [A Project command] *************************************************************
           changed: [10.0.0.12]
           changed: [10.0.0.13]
   
   TASK [Restart Httpd Server] **********************************************************
           changed: [10.0.0.12]
           changed: [10.0.0.13]
   
   PLAY RECAP ***************************************************************************
           10.0.0.12                  : ok=2    changed=2    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0
           10.0.0.13                  : ok=2    changed=2    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0
   
   [root@manager control]# ansible-playbook b_project.yml
   
   PLAY [webservers] ********************************************************************
   
   TASK [B Project command] *************************************************************
       changed: [10.0.0.12]
       changed: [10.0.0.13]
   
   TASK [Restart Httpd Server] **********************************************************
       changed: [10.0.0.13]
       changed: [10.0.0.12]
   
   PLAY RECAP ***************************************************************************
       10.0.0.12                  : ok=2    changed=2    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0
       10.0.0.13                  : ok=2    changed=2    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0
   
   

案例2-Inlcude结合tags应用

• 通过指定标签tags，来说明是安装tomcat8还是tomcat9
  • 准备入口main.yml文件，然后包含install_tomcat8.yml以及install_tomcat9.yml
  • 在执行main.yml时，需要通过--tags指明要安装的版本

1. 编写main.yml入口文件

   [root@manager control]# cat main.yml
   - hosts: localhost
     tasks:
       - name: Installed Tomcat8 Version
         include: install_tomcat8.yml
         tags: tomcat8
   
       - name: Installed Tomcat9 Version
         include: install_tomcat9.yml
         tags: tomcat9
   
   

2. 编写install_tomcat8.yml

   [root@manager control]# cat install_tomcat8.yml
   - hosts: webservers
     vars:
       - tomcat_version: 8.5.63
       - tomcat_install_dir: /usr/local
     tasks:
       - name: Install jdk1.8
         yum:
           name: java-1.8.0-openjdk
           state: present
   
       - name: Download tomcat
         get_url:
           url: http://mirrors.hust.edu.cn/apache/tomcat/tomcat-8/v{{ tomcat_version }}/bin/apache-tomcat-{{ tomcat_version}}.tar.gz
           dest: /tmp
   
       - name: Unarchive tomcat-{{ tomcat_version }}.tar.gz
         unarchive:
           src: /tmp/apache-tomcat-{{ tomcat_version }}.tar.gz
           dest: "{{ tomcat_install_dir }}"
           copy: no
   
       - name: Start tomcat
         shell: cd {{ tomcat_install_dir }} &&
               mv apache-tomcat-{{ tomcat_version }} tomcat8 &&
               cd tomcat8/bin && nohup ./startup.sh &
   
   

3. 编写install_tomcat9.yml

   [root@manager control]# cat install_tomcat9.yml
   - hosts: webservers
     vars:
       - tomcat_version: 9.0.43
       - tomcat_install_dir: /usr/local
     tasks:
       - name: Install jdk1.8
         yum:
           name: java-1.8.0-openjdk
           state: present
   
       - name: Download tomcat
         get_url:
           url: http://mirrors.hust.edu.cn/apache/tomcat/tomcat-9/v{{ tomcat_version }}/bin/apache-tomcat-{{ tomcat_version}}.tar.gz
           dest: /tmp
   
       - name: Unarchive tomcat-{{ tomcat_version }}.tar.gz
         unarchive:
           src: /tmp/apache-tomcat-{{ tomcat_version }}.tar.gz
           dest: "{{ tomcat_install_dir }}"
           copy: no
   
       - name: Start tomcat
         shell: cd {{ tomcat_install_dir }} &&
               mv apache-tomcat-{{ tomcat_version }} tomcat8 &&
               cd tomcat8/bin && nohup ./startup.sh &
   
   

4. 执行main.yml文件，然后通过--tags执行对应的版本

   [root@manager control]# ansible-playbook main.yml --tags tomcat8
   [root@manager control]# ansible-playbook main.yml --tags tomcat9
   

Playbook异常处理

案例1-Playbook错误忽略

在playbook执行的过程中，难免会遇到一些错误。由于playbook遇到错误后，不会执行之后的任务，不便于调试，此时，可以使用ignore_errors来暂时忽略错误，使得playbook继续执行。

1. 编写playbook，当有task执行失败则会立即终止后续task运行

   [root@manager control]# cat ignore.yml
   - hosts: all
     remote_user: root
     tasks:
       - name: Ignore False
         command: /bin/false
   
       - name: touch new file
         file: path=/tmp/bi_ignore state=touch
   
   

2. 执行playbook，会报错，后续的任务也没有执行。

   [root@manager control]# ansible-playbook ignore.yml
   PLAY [all] ***************************************************************************
   
   TASK [Ignore False] ******************************************************************
           fatal: [10.0.0.12]: FAILED! => {"changed": true, "cmd": ["/bin/false"], "delta": "0:00:00.003536", "end": "2022-03-28 08:53:15.630142", "msg": "non-zero return code", "rc": 1, "start": "2022-03-28 08:53:15.626606", "stderr": "", "stderr_lines": [], "stdout": "", "stdout_lines": []}
           fatal: [10.0.0.13]: FAILED! => {"changed": true, "cmd": ["/bin/false"], "delta": "0:00:00.003847", "end": "2022-03-28 08:53:09.886954", "msg": "non-zero return code", "rc": 1, "start": "2022-03-28 08:53:09.883107", "stderr": "", "stderr_lines": [], "stdout": "", "stdout_lines": []}
   
   PLAY RECAP ***************************************************************************
           10.0.0.12                  : ok=0    changed=0    unreachable=0    failed=1    skipped=0    rescued=0    ignored=0
           10.0.0.13                  : ok=0    changed=0    unreachable=0    failed=1    skipped=0    rescued=0    ignored=0
   
   

3. 此时我们给对应的task任务添加忽略错误

   [root@manager control]# cat ignore.yml
   - hosts: all
     remote_user: root
     tasks:
       - name: Ignore False
         command: /bin/false
         ignore_errors: yes
   
       - name: touch new file
         file: path=/tmp/bi_ignore state=touch
   

4. 再次执行playbook如果碰到指定的tasks错误，会自动忽略，继续执行剩下的tasks

   [root@manager control]# ansible-playbook ignore.yml
   PLAY [all] ***************************************************************************
   TASK [Ignore False] ******************************************************************
       fatal: [10.0.0.12]: FAILED! => {"changed": true, "cmd": ["/bin/false"], "delta": "0:00:00.003070", "end": "2022-03-28 08:53:51.214443", "msg": "non-zero return code", "rc": 1, "start": "2022-03-28 08:53:51.211373", "stderr": "", "stderr_lines": [], "stdout": "", "stdout_lines": []}
       ...ignoring
       fatal: [10.0.0.13]: FAILED! => {"changed": true, "cmd": ["/bin/false"], "delta": "0:00:00.003109", "end": "2022-03-28 08:53:45.470045", "msg": "non-zero return code", "rc": 1, "start": "2022-03-28 08:53:45.466936", "stderr": "", "stderr_lines": [], "stdout": "", "stdout_lines": []}
           ...ignoring
   
   TASK [touch new file] ****************************************************************
       changed: [10.0.0.12]
       changed: [10.0.0.13]
   
   PLAY RECAP ***************************************************************************
       10.0.0.12                  : ok=2    changed=2    unreachable=0    failed=0    skipped=0    rescued=0    ignored=1
       10.0.0.13                  : ok=2    changed=2    unreachable=0    failed=0    skipped=0    rescued=0    ignored=1
   
   

案例2-task执行失败强制调用handlers

通常情况下，当task失败后，play将会终止，任何在前面已经被tasks notify的handlers都不会被执行。如果你在play中设置了force_handlers: yes参数，被通知的handlers就会被强制执行。(有些特殊场景可能会使用到)

1. 编写playbook

   [root@manager control]# cat igno_handlers.yml
   - hosts: webservers
     force_handlers: yes #强制调用handlers
     tasks:
       - name: Touch File
         file: path=/tmp/bgx_handlers state=touch
         notify: Restart Httpd Server
   
       - name: Installed Packages
         yum: name=sb state=latest
   
     handlers:
     - name: Restart Httpd Server
       service: name=httpd state=restarted
   

2. 执行playbook

   [root@manager control]# ansible-playbook igno_handlers.yml
   PLAY [webservers] ********************************************************************
   
   TASK [Touch File] ********************************************************************
           changed: [10.0.0.12]
           changed: [10.0.0.13]
   
   TASK [Installed Packages] ************************************************************
           fatal: [10.0.0.13]: FAILED! => {"changed": false, "msg": "No package matching 'sb' found available, installed or updated", "rc": 126, "results": ["No package matching 'sb' found available, installed or updated"]}
           fatal: [10.0.0.12]: FAILED! => {"changed": false, "msg": "No package matching 'sb' found available, installed or updated", "rc": 126, "results": ["No package matching 'sb' found available, installed or updated"]}
   
   RUNNING HANDLER [Restart Httpd Server] ***********************************************
           changed: [10.0.0.12]
           changed: [10.0.0.13]
   
   PLAY RECAP ***************************************************************************
       10.0.0.12                  : ok=2    changed=2    unreachable=0    failed=1    skipped=0    rescued=0    ignored=0
       10.0.0.13                  : ok=2    changed=2    unreachable=0    failed=1    skipped=0    rescued=0    ignored=0
   
   

案例3-控制Tasks报告状态为OK

1. 编辑playbook

   [root@manager control]# cat change.yml
   - hosts: webservers
     tasks:
       #获取系统httpd服务启动状态,将其结果写入Httpd_Port变量中
       - name: Get Httpd Server Port
         shell: netstat -lntp|grep httpd
         register: Httpd_Port
   
       #输出Httpd_Port变量中的内容
       - name: Out Httpd Server Status
         debug: msg={{ Httpd_Port.stdout_lines }}
         ignore_errors: yes
   
   

2. 执行playbook会发现第一个task运行shell模块报告的改变，即使它没有真正的在远端系统做出改变，如果你一直运行，它会一直处在改变状态。

   [root@manager control]# ansible-playbook change.yml
   PLAY [webservers] ********************************************************************
   
   TASK [Get Httpd Server Port] *********************************************************
           changed: [10.0.0.13]
           changed: [10.0.0.12]
   
   TASK [Out Httpd Server Status] *******************************************************
           ok: [10.0.0.12] => {
               "msg": [
                   "tcp6       0      0 :::8882                 :::*                    LISTEN      27796/httpd         "
           ]
           }
           ok: [10.0.0.13] => {
               "msg": [
                   "tcp6       0      0 :::8882                 :::*                    LISTEN      53135/httpd         "
               ]
           }
   
   PLAY RECAP ***************************************************************************
       10.0.0.12                  : ok=2    changed=1    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0
       10.0.0.13                  : ok=2    changed=1    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0
   
   

3. shell任务不应该每次都报告changed状态，因为它没有在被管理主机执行后发生变化。添changed_when: false来抑制这个改变

   [root@manager control]# cat change.yml
   - hosts: webservers
     tasks:
       #获取系统httpd服务启动状态,将其结果写入Httpd_Port变量中
       - name: Get Httpd Server Port
         shell: netstat -lntp|grep httpd
         register: Httpd_Port
         changed_when: false #该task不发生changed提示
   
       #输出Httpd_Port变量中的内容
       - name: Out Httpd Server Status
         debug: msg={{ Httpd_Port.stdout_lines }}
         ignore_errors: yes
   
   

4. 再次执行playbook

   [root@manager control]# ansible-playbook change.yml
   PLAY [webservers] ********************************************************************
   
   TASK [Get Httpd Server Port] *********************************************************
       ok: [10.0.0.13]
       ok: [10.0.0.12]
   
   TASK [Out Httpd Server Status] *******************************************************
       ok: [10.0.0.12] => {
           "msg": [
               "tcp6       0      0 :::8882                 :::*                    LISTEN      27796/httpd         "
       ]
       }
       ok: [10.0.0.13] => {
           "msg": [
               "tcp6       0      0 :::8882                 :::*                    LISTEN      53135/httpd         "
           ]
       }
   
   PLAY RECAP ***************************************************************************
   10.0.0.12                  : ok=2    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0
   10.0.0.13                  : ok=2    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0