Ansible 流程控制

一、playbook条件语句

不管是shell还是各大变成语言中，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.稍微修改lnmp.yml

#修改部分，使用自己配置好的博客站点目录
- name: Install Wordpress Code
  unarchive:
    src: /root/blog.tar.gz
    dest: /

#添加数据库导入部分
- name: Post wordpress.sql
  copy:
    src: /root/db01/root/wordpress.sql
    dest: /tmp/
    
- name: Import wordpress.sql
  mysql_db:
    state: import
    name: wordpress
    target: /tmp/wordpress.sql

2.判断主机

- name: Create www Group    #如果主机名等于web01,执行下方命令
  group:
    name: www
    gid: 666
    state: present
  when: ansible_fqdn == "web01"    #判断语句中变量不需要加大括号和引号,因为不需要打印
  #when: ansible_fqdn is match "web*"    #当主机名匹配web*，用于多台web
  #when: ansible_fqdn != "db01"    #当主机名不等于db01
  
- name: Create www User    #如果主机名等于web01或web02执行下方命令
  user:
    name: www
    gid: 666
    group: www
    create_home: false
    shell: /sbin/nologin
    state: present
  when: (ansible_fqdn == "web01") or (ansible_fqdn == "web02")    # ()加or表示多个

3.如何判断服务是否安装

通过rpm -qa|grep php 命令返回的$?来判断是否已经安装，0表示安装，1表示未安装

- hosts: web01
  tasks:
    #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    #获取状态，加上忽略错误(否则非0报错,不往下执行)
      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:    #输出
        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    #rc就是$?返回

4.判断系统

[root@m01 base]# vim xitong.yml
- 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"

5.判断系统版本

[root@m01 base]# vim start.yml
- 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"

6.可以通过提示决定是否执行

#当企业里有很多版本的系统时，先判断版本是否支持服务再进行操作
tasks:
  - shell: echo "only on Red Hat 6, derivatives, and later"
    when: ansible_facts['os_family'] == "RedHat" and ansible_facts['lsb']['major_release']|int >= 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 and Nginx Server
      systemd:
        name: "{{ server }}"
        state: started
        enabled: yes
      vars:    #同时执行，当成一个字符串
        server:
          - php-fpm
          - nginx
          
#正确做法
    - name: Start PHP and Nginx Server
      systemd:
        name: "{{ item }}"    #固定写法
        state: started
        enabled: yes
      with_items:    #固定写法,设置变量,一个一个执行
        - php-fpm
        - nginx

3.字典定义变量

    #创建用户组
    - name: Create www lhd test Group
      group:
        name: "{{ item.name }}"
        gid: "{{ item.gid }}"
        state: present
      with_items:
        - { name: "www", gid: "666"}
        - { name: "lhd", gid: "777"}
        - { name: "test", gid: "888"}
    
    #创建多个用户
    - name: Create www lhd test 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: "true", shell: "/sbin/nologin"}
        - { name: "test", uid: "888", group: "test", create_home: "false", shell: "/bin/bash"}
        
    #创建多个目录(赋权,没有目录就会创建)
    - 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" }

4.利用字典定义方式优化lnmp.yml

    - 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/" }


    - name: Tar PHP and Wordpress Package
      unarchive:
        src: "{{ item.src }}"
        dest: "{{ item.dest }}"
      with_items:
        - { src: "/root/php.tar.gz", dest: "/tmp/" }
        - { src: "/root/blog.tar.gz", dest: "/" }