Task execution control in Ansible

目录

一.循环

1.简单循环

2.循环散列或字典列表

二.条件

when: - 条件1 - 条件

 多条条件组合

三.触发器

四.处理失败任务

1.ignore_errors

2.force_handlers

 3.changed_when

4.failed_when

5.block

测试练习

磁盘划分

2.建立userlist.yml中的用户,And make user password encrypted,

---

一.循环

循环迭代任务

1.简单循环

- name: test play

  hosts: westos

  tasks:

    - debug:

        msg: "{ {item}}"

      loop:

        - westos

        - linux

        - lee

2.循环散列或字典列表

- name: test play

   hosts: westos

   tasks:

     - debug:

         msg: "{ {item.name}} { {item.age}}"

       loop:

         - { name: westos, age: 18 }

         - { name: linux, age: 19 }

         - { name: lee, age: 20 }

 

二.条件

when: - 条件1 - 条件

2     条件判断

=	value == "字符串",value == 数字
<	value < 数字
>	value > 数字
<=	value <= 数字
>=	value >= 数字
!=	value != 数字
is defined	value is defined变量存在
is not defined	value is not defined    变量不存在
in	value is in value 变量为
not in	value is not in value 变量不为
bool变量 为true	value的值为true
bool变量 false	value的值为false

 多条条件组合

when：

条件1 and 条件2

- 条件1

- 条件2

when:

条件1 or 条件2

when: >

条件1

or

条件2

三.触发器

notify: 触发器当遇到更改是触发handlers

handlers：触发器触发后执行的动作

实例:安装Apache,更改端口为8080,如果更改,并重启Apache,触发触发器;如果端口号是8080未被修改,则不需要重启,Triggers are not fired

- name: apache server

  hosts: westos

  vars:

    port: 8080

  tasks:

    - name: install httpd

      dnf:

        name: httpd

        state: present

    - name: set config

      lineinfile:

        path: /etc/httpd/conf/httpd.conf

        regexp: ^Listen

        line: "Listen { {port}}"

      notify: restart apache

    - name: enable filewalld

      firewalld:

        port: "{ {port}}/tcp"

        permanent: yes

        immediate: yes

        state: enabled

- name: state apache

      service:

        name: httpd

        state: started

        enabled: yes

  handlers:

    - name: restart apache

      service:

        name: httpd

        state: restarted

四.处理失败任务

1.ignore_errors

作用：

当play遇到任务失败时会终止,ignore_errors: yes将会忽略任务失败使下面的任务继续运行

实例：执行install software play失败后会执行show some message play模块

- name: test play

  hosts: westos

  tasks:

    - name: inatall software

      dnf:

        name: http（错误）

        state: present

      ignore_errors: yes

    - name: show some message

      debug:

        msg: hello westos

 

2.force_handlers

作用：当任务失败后play被终止,Trigger processes are also invoked

- name: test play

  hosts: westos

  force_handlers: yes

  tasks:

    - name: test

      shell: ls /mnt/

    - name: install software

      dnf:

        name: http（错误）

        state: present

    - name: show some massages

      debug:

        msg: hello westos

  handlers:

    - name: notify messages

      debug:

        msg: hello notify

 

 3.changed_when

作用： 控制任务在何时报告它已进行更改,with or without changes,are considered changes

- name: test play

  hosts: westos

  tasks:

    - name: install software

      dnf:

        name: http（错误）

        state: present

      changed_when: yes

      notify: notify message

    - name: show some message

      debug:

        msg: hello westos

   handlers:

     - name: notify message

       debug:

         msg: hello notify

4.failed_when

当符合条件时强制任务失败 （Failed or not,Forced to fail）

- name: test play

  hosts: westos

  tasks:

    - name: install software

      dnf:

        name: http（错误）

        state: present

      failed_when: yes

      notify: notify message

    - name: show some message

      debug:

        msg: hello westos

   handlers:

     - name: notify message

       debug:

         msg: hello notify

 

5.block

block:           定义要运行的任务

rescue:          定义当block句子中出现失败任务后运行的任务

always：       定义最终独立运行的任务

- name: test play

  hosts: westos

  force_handlers: yes

  tasks:

    - name: test block

      block:

        - name: install software

          dnf:

            name: http（错误）

            state: present

      rescue:

        - name: show error

          debug:

            msg: http is not exist

      always:

        - name: show message

          debug:

            msg: over

测试练习

磁盘划分

1.建立playbook ~/westos.yml

要求如下: 建立大小为1500M名为/dev/vdb1的设备 如果/dev/vdb不存在请输入: /dev/vdb is not exist 如果/dev/vdb大小不足2G请输出： /dev/vdb is less then 2G 并建立800M大小的/dev/vdb1 此设备挂载到/westos上

- name: test

  hosts: westos

  tasks:

    - name: /dev/sdb is not exist

      debug:

        msg: /dev/sdb is not exist

      when:

        ansible_facts['devices']['sdb'] is not defined

    - name: create_storage

      block:

        - name: create 1500M

          parted:

            device: /dev/sdb

            number: 1

            state: present

            part_end: 1500MiB

          when:

            ansible_facts['devices']['sdb'] is  defined

      rescue:

        - name: create 800M

          parted:

            device: /dev/sdb

            number: 1

            state: present

            part_end: 800MiB

          when:

            ansible_facts['devices']['sdb'] is defined

        - name: device messages

          debug:

            msg: /dev/sdb is less 2G

          when:

            ansible_facts['devices']['sdb'] is defined

      always:

        - name: create filesystem

          filesystem:

            fstype: xfs

            dev: /dev/sdb1

        - name:

          file:

            path: /westos

            state: directory

        - name: mount devices

          mount:

            path: /westos

            src: /dev/sdb1

            fstype: xfs

            state: mounted

      when:

        ansible_facts['devices']['sdb'] is defined

 

2.建立userlist.yml中的用户,And make user password encrypted,

vim userlist.yml

 

vim useradd.yml