ansible的条件判断、迭代执行、tags

32去2

在ansible中支持条件判断，这使我们操作更加灵活
使用when进行条件测试
示例1：
将 testservers 组中的其中一台主机上的 httpd 服务卸载掉，另外主机不卸载

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[iyunv@node1 ansible]# ansible testservers -m shell -a 'rpm -q httpd' 192.168.100.131 | success | rc=0 >> httpd-2.2.15-29.el6.centos.x86_64 192.168.100.132 | success | rc=0 >> httpd-2.2.15-47.el6.centos.3.x86_64 [iyunv@node1 ansible]# cat http.yml - hosts: testservers   remote_user: root   tasks:   - name: uninstall httpd service     yum: name=httpd state=absent     when: ansible_nodename == "v2.lansgg.com"       [iyunv@node1 ansible]# ansible-playbook http.yml PLAY [testservers] ************************************************************ GATHERING FACTS *************************************************************** ok: [192.168.100.131] ok: [192.168.100.132] TASK: [uninstall httpd service] *********************************************** skipping: [192.168.100.132] changed: [192.168.100.131] PLAY RECAP ******************************************************************** 192.168.100.131            : ok=2    changed=1    unreachable=0    failed=0    192.168.100.132            : ok=1    changed=0    unreachable=0    failed=0    [iyunv@node1 ansible]# ansible testservers -m shell -a 'rpm -q httpd' 192.168.100.132 | success | rc=0 >> httpd-2.2.15-47.el6.centos.3.x86_64 192.168.100.131 | FAILED | rc=1 >> package httpd is not installed [iyunv@node1 ansible]#

示例2：
也可以使用 or 进行 或 判断，这里将组内的两台主机的 httpd 服务都卸载，

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[iyunv@node1 ansible]# ansible testservers -m shell -a 'rpm -q httpd' 192.168.100.132 | success | rc=0 >> httpd-2.2.15-47.el6.centos.3.x86_64 192.168.100.131 | success | rc=0 >> httpd-2.2.15-29.el6.centos.x86_64 [iyunv@node1 ansible]# cat http.yml - hosts: testservers   remote_user: root   tasks:   - name: uninstall httpd service     yum: name=httpd state=absent     when: (ansible_nodename == "v2.lansgg.com") or ( ansible_all_ipv4_addresses[0] == '192.168.100.132')       [iyunv@node1 ansible]# ansible-playbook http.yml PLAY [testservers] ************************************************************ GATHERING FACTS *************************************************************** ok: [192.168.100.131] ok: [192.168.100.132] TASK: [uninstall httpd service] *********************************************** changed: [192.168.100.131] changed: [192.168.100.132] PLAY RECAP ******************************************************************** 192.168.100.131            : ok=2    changed=1    unreachable=0    failed=0    192.168.100.132            : ok=2    changed=1    unreachable=0    failed=0    [iyunv@node1 ansible]# ansible testservers -m shell -a 'rpm -q httpd' 192.168.100.131 | FAILED | rc=1 >> package httpd is not installed 192.168.100.132 | FAILED | rc=1 >> package httpd is not installed [iyunv@node1 ansible]#

保存结果几乎所有的模块都是会outputs一些东西,甚至debug模块也会.大多数我们会使用的结果变量是changed.这个changed变量决定了是否要直接handlers和输出的颜色是什么.然而,结果变量还有其他的用途,譬如我需要保存我的结果变量,然后在我们的playbook的其他地方使用.
示例：
分别在一台主机上创建一个目录，另外主机不存在此目录，根据此目录的存在情况，做出不同操作

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[iyunv@node1 ansible]# ansible testservers -m shell -a 'ls -l /nono' 192.168.100.131 | success | rc=0 >> total 0 192.168.100.132 | FAILED | rc=2 >> ls: cannot access /nono: No such file or directory [iyunv@node1 ansible]# cat re.yml - hosts: testservers   remote_user: root   tasks:    - name: ls /nono      shell: /bin/ls /nono      register: result      ignore_errors: True    - name: test result      copy: content="ok" dest=/tmp/test      when: result.rc == 0    - name: test no result      copy: content="no ok" dest=/tmp/test      when: result.rc != 0        [iyunv@node1 ansible]# ansible-playbook re.yml PLAY [testservers] ************************************************************ GATHERING FACTS *************************************************************** ok: [192.168.100.131] ok: [192.168.100.132] TASK: [ls /nono] ************************************************************** changed: [192.168.100.131] failed: [192.168.100.132] => {"changed": true, "cmd": "/bin/ls /nono", "delta": "0:00:00.004437", "end": "2016-03-02 12:56:55.409736", "rc": 2, "start": "2016-03-02 12:56:55.405299", "warnings": []} stderr: /bin/ls: cannot access /nono: No such file or directory ...ignoring TASK: [test result] *********************************************************** skipping: [192.168.100.132] ok: [192.168.100.131] TASK: [test no result] ******************************************************** skipping: [192.168.100.131] ok: [192.168.100.132] PLAY RECAP ******************************************************************** 192.168.100.131            : ok=3    changed=1    unreachable=0    failed=0    192.168.100.132            : ok=3    changed=1    unreachable=0    failed=0    [iyunv@node1 ansible]# ansible testservers -m shell -a 'ls -l /tmp/test' 192.168.100.131 | success | rc=0 >> -rw-r--r-- 1 root root 2 Mar  2 12:55 /tmp/test 192.168.100.132 | success | rc=0 >> -rw-r--r-- 1 root root 5 Mar  2 12:55 /tmp/test [iyunv@node1 ansible]# ansible testservers -m shell -a 'cat /tmp/test' 192.168.100.131 | success | rc=0 >> ok 192.168.100.132 | success | rc=0 >> no ok [iyunv@node1 ansible]#

ansible 中的循环操作：
当有需要重复性执行的任务时，可以使用迭代机制，格式为：将需要迭代的内容定义为Item变量引用，并通过with_items 语句来指明迭代的元素列表即可
示例1、
在 testservers 组中一台主机上安装lamp

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[iyunv@node1 ansible]# cat item.yml - hosts: testservers   remote_user: root   tasks:    - name: yum install lamp      yum: name={{item}} state=present      with_items:          - httpd          - mysql-server          - php      when: (ansible_nodename == "v2.lansgg.com") [iyunv@node1 ansible]#

上面的语句等同于：

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- hosts: testservers   remote_user: root   tasks:   - name: install httpd     yum: name=httpd state=present     when: (ansible_nodename == "v2.lansgg.com")   - name: install mysql-server     yum: name=mysql-server state=present     when: (ansible_nodename == "v2.lansgg.com")   - name: install php     yum: name=php state=present     when: (ansible_nodename == "v2.lansgg.com")

上面的语句 hash 方式编写也可以，等同于如下：

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- hosts: testservers   remote_user: root   tasks:    - name: install httpd      yum: name={{item.name}} state={{item.state}}      when: (ansible_nodename == "v2.lansgg.com")      with_items:       - {name: 'httpd', state: 'present'}       - {name: 'mysql-server', state: 'present'}       - {name: 'php', state: 'present'}

开始执行：

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[iyunv@node1 ansible]# ansible-playbook item.yml PLAY [testservers] ************************************************************ GATHERING FACTS *************************************************************** ok: [192.168.100.131] ok: [192.168.100.132] TASK: [yum install lamp] ****************************************************** skipping: [192.168.100.132] changed: [192.168.100.131] => (item=httpd,mysql-server,php) PLAY RECAP ******************************************************************** 192.168.100.131            : ok=2    changed=1    unreachable=0    failed=0    192.168.100.132            : ok=1    changed=0    unreachable=0    failed=0

ansible 的 tags 功能

ansible的playbool中有一个关键字，叫做tags。tags是什么？就是打标签。tags可以和一个play（就是很多个task）或者一个task进行捆绑。然后，ansible-playbook提供了“--skip-tags”和“--tags” 来指明是跳过特定的tags还是执行特定的tags。
示例 1、

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[iyunv@node1 ansible]# cat tag.yml - hosts: testservers   remote_user: root   tasks:    - name: echo A1      command: echo A1      tags:       - A1    - name: echo A2      command: echo A2      tags:       - A2    - name: echo A3      command: echo A3      tags:       - A3

当执行  ansible-playbook tag.yml --tags="A1,A3  ,则只会执行A1和A3的echo命令。
如下：

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[iyunv@node1 ansible]# ansible-playbook tag.yml --tags="A1,A3" PLAY [testservers] ************************************************************ GATHERING FACTS *************************************************************** ok: [192.168.100.131] ok: [192.168.100.132] TASK: [echo A1] *************************************************************** changed: [192.168.100.131] changed: [192.168.100.132] TASK: [echo A3] *************************************************************** changed: [192.168.100.131] changed: [192.168.100.132] PLAY RECAP ******************************************************************** 192.168.100.131            : ok=3    changed=2    unreachable=0    failed=0    192.168.100.132            : ok=3    changed=2    unreachable=0    failed=0

当执行  ansible-playbook tag.yml --skip-tags="A2" ,同样只会执行 A1和A3的echo命令。
如下：

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[iyunv@node1 ansible]# ansible-playbook tag.yml --skip-tags="A2" PLAY [testservers] ************************************************************ GATHERING FACTS *************************************************************** ok: [192.168.100.131] ok: [192.168.100.132] TASK: [echo A1] *************************************************************** changed: [192.168.100.132] changed: [192.168.100.131] TASK: [echo A3] *************************************************************** changed: [192.168.100.131] changed: [192.168.100.132] PLAY RECAP ******************************************************************** 192.168.100.131            : ok=3    changed=2    unreachable=0    failed=0    192.168.100.132            : ok=3    changed=2    unreachable=0    failed=0

示例 2 、
我们安装 httpd 服务的流程为 安装服务、copy文件、启动服务、如果配置有变化就重启服务，

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[iyunv@node1 ansible]# cat http.yml - hosts: testservers   remote_user: root   tasks:   - name: install httpd package     yum: name=httpd state=present   - name: start httpd service     service: name=httpd enabled=true state=started   - name: copy config file     copy: src=httpd.conf dest=/etc/httpd/conf/httpd.conf     notify:        restart httpd service     tags:      - modify   handlers:    - name: restart httpd service      service: name=httpd state=restarted [iyunv@node1 ansible]#

当我们的配置文件有修改的时候，可以指定tags，这样就会只执行copy config file 任务，前面就不会再执行
结果如下：

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[iyunv@node1 ansible]# ansible-playbook http.yml --tags=modify PLAY [testservers] ************************************************************ GATHERING FACTS *************************************************************** ok: [192.168.100.131] ok: [192.168.100.132] TASK: [copy config file] ****************************************************** changed: [192.168.100.131] changed: [192.168.100.132] NOTIFIED: [restart httpd service] ********************************************* changed: [192.168.100.131] changed: [192.168.100.132] PLAY RECAP ******************************************************************** 192.168.100.131            : ok=3    changed=2    unreachable=0    failed=0    192.168.100.132            : ok=3    changed=2    unreachable=0    failed=0