Ansible自动化企业实战——ansible流程控制

文章目录[隐藏]

一、playbook条件语句
二、playbook循环语句
三、ansible handlers（触发器）

一、playbook条件语句

不管是shell还是各大编程语言中，流程控制，条件判断这些都是必不可少的，在我们使用Ansible的过程中，条件判断的使用频率极其高。
例如：
1.我们使用不同的系统的时候，可以通过判断系统来对软件包进行安装。
2.在nfs和rsync安装过程中，客户端服务器不需要推送配置文件，之前我们都是写多个play，会影响效率。
3.我们在源码安装nginx的时候，执行第二遍就无法执行了，此时我们就可以进行判断是否安装过。

1.判断主机

    - name: Create www Group
      group:
        name: www
        gid: 666
        state: present
      when: ansible_fqdn == "web01"

    - name: Create www User
      user:
        name: www
        uid: 666
        group: www
        create_home: false
        shell: /sbin/nologin
        state: present
      when: ansible_fqdn == "web01"

2.如何判断服务是否安装

    #执行shell，判断服务是否安装，并把结果注册一个变量
    - name: Get PHP Install Status
      shell: "rpm -qa | grep php"
      ignore_errors: yes
      register: get_php_install_status

	#调用变量，查看内容，如果知道使用什么值判断可以不写
    - name: Get get_php_install_status
      debug:
        msg: "{{ get_php_install_status }}"

	#调用变量结果，rc值不等于0时执行安装命令
    - name: Install PHP Server
      shell: "yum localinstall -y /tmp/*.rpm"
      when: get_php_install_status.rc != 0

3.判断系统

- hosts: web01
  tasks:
    - name: Install CentOS apache
      shell: "yum install -y httpd"
      when: ansible_distribution == "CentOS"

    - name: Install Ubuntu apache
      shell: "apt-get apache"
      when: ansible_distribution == "Ubuntu"

4.判断系统版本

- hosts: web01
  tasks:
    - name: Start CentOS6 apache
      shell: "/etc/init.d/httpd start"
      when: (ansible_distribution == "CentOS") and (ansible_distribution_major_version == "6")

    - name: Install Ubuntu apache
      shell: "apt-get apache"
      when: (ansible_distribution == "CentOS") and (ansible_distribution_major_version == "7")
      
#指定多个条件，除了用and，还可以使用列表形式
- hosts: web01
  tasks:
    - name: Start CentOS6 apache
      shell: "/etc/init.d/httpd start"
      when: 
        - ansible_distribution == "CentOS"
        - ansible_distribution_major_version == "6"

    - name: Install Ubuntu apache
      shell: "apt-get apache"
      when: 
        - ansible_distribution == "CentOS"
        - ansible_distribution_major_version == "7"

二、playbook循环语句

1.定义变量循环安装

- hosts: db01
  tasks:
    - name: Install Mariadb Server
      yum:
        name: "{{ package }}"
        state: present
      vars:
        package:
          - mariadb-server
          - MySQL-python

2.定义变量启动服务

#错误配置方法
    - name: Start PHP Server
      systemd:
        name: "{{ server }}"
        state: started
        enabled: yes
      vars:
        server:
          - php-fpm
          - nginx
          
#正确写法
    - name: Start PHP and Nginx Server
      systemd:
        name: "{{ item }}"
        state: started
        enabled: yes
      with_items:
        - nginx
        - php-fpm

3.字典定义变量

    #创建用户组
    - name: Create www Group
      group:
        name: "{{ item.name }}"
        gid: "{{ item.gid }}"
        state: present
      with_items:
        - { name: "www", gid: "666" }
        - { name: "lhd", gid: "777" }
        - { name: "test", gid: "888" }
      when: ansible_fqdn == "web01"

	#创建多个用户
    - name: Create www User
      user:
        name: "{{ item.name }}"
        uid: "{{ item.uid }}"
        group: "{{ item.group }}"
        create_home: "{{ item.create_home }}"
        shell: "{{ item.shell }}"
        state: present
      with_items:
        - { name: "www", uid: "666", group: "www", create_home: "false", shell: "/sbin/nologin" }
        - { name: "lhd", uid: "777", group: "lhd", create_home: "ture", shell: "/sbin/nologin" }
        - { name: "test", uid: "888", group: "test", create_home: "false", shell: "/bin/bash" }
        
    #创建多个目录
    - name: Chown Code Dir
      file:
        path: "{{ item.path }}"
        state: directory
        owner: "{{ item.user }}"
        group: "{{ item.user }}"
        recurse: yes
      with_items:
        - { path: "/code", user: "www" }
        - { path: "/data", user: "lhd" }

三、ansible handlers（触发器）

1.handlers作用

handler用来执行某些条件下的任务，比如当配置文件发生变化的时候，通过notify触发handler去重启服务。
在saltstack中也有类似的触发器，写法相对Ansible简单，只需要watch，配置文件即可。

2.配置触发器

    - name: Config Nginx Server
      copy:
        src: "{{ item.src }}"
        dest: "{{ item.dest }}"
      with_items:
        - { src: "/root/nginx.conf", dest: "/etc/nginx/" }
        - { src: "/root/wordpress.conf", dest: "/etc/nginx/conf.d/" }
      notify: restart_nginx
      
  handlers:
    - name: restart_nginx
      systemd:
        name: nginx
        state: restarted