Ansible的流程控制

playbook的流程控制

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。

#### 根据不同的系统安装apach
tasks:
  - name: "shut down Debian flavored systems"
    command: /sbin/shutdown -t now
    when: ansible_facts['os_family'] == "Debian"

- hosts: all
  tasks:
    - name: Install CentOS Httpd
      yum:
        name: httpd
        state: present
    #官方
      when: ansible_facts['os_family'] == "CentOS"
    #非官方
      when: ansible_distribution == "CentOS"
 
    - name: Install Ubuntu Httpd
      apt:
        name: apache2
        state: present
      when: ansible_facts['os_family'] == "Debian"

使用括号进行分组

- hosts: aaa01  # 替换为具体的主机名
  tasks:
    - name: " CentOS 6 和 Debian 24 系统创建 111 目录"
      command: mkdir 111
      when: (ansible_facts['distribution'] == "CentOS" and ansible_facts['distribution_major_version'] == "6") or (ansible_facts['distribution'] == "Ubuntu" and ansible_facts['distribution_major_version'] == "24")

也可以指定多条件为列表

- hosts: aaa01  # 替换为具体的主机名	
  tasks:
    - name: "创建 目录"
      command: mkdir 2222
      when:
        - ansible_facts['distribution'] == "Ubuntu"
        - ansible_facts['distribution_major_version'] == "24"

条件运算

- hosts: all	
  tasks:
    - shell: 'echo "这是德便linux系统 ，系统版本大于6" >22.txt'
      when: ansible_facts['os_family'] == "Debian" and ansible_facts['lsb']['major_release']|int >= 6

定义循环语句

在之前的学习过程中，我们经常会有传送文件，创建目录之类的操作，创建2个目录就要写两个file模块来创建，如果要创建100个目录，我们需要写100个file模块？，只要有循环即可，减少重复性代码。

- hosts: all
  tasks:
    - name: start service
      systemd:
        name: "{{ item }}"
        state: started
      with_items:
        - httpd
        - php-fpm
        - mariadb

#### 定义变量循环
- name: ensure a list of packages installed
  apt:
    name: "{{ packages }}"
  vars:
    packages:
    - httpd
    - httpd-tools
    
- hosts: web_group
  tasks:
    - name: ensure a list of packages installed
      apt: name= "{{ item }}" state=present
      with_items:
        - nginx
        - mariadb-server

定义字典循环

#### 创建用户
cat loop.yml
- hosts: web_group
  tasks:
    - name: Add Users
      user:
        name: "{{ item.name }}"
        groups: "{{ item.groups }}"
        state: present
      with_items:
        - { name: 'zls', groups: 'linux' }
        - { name: 'egon', groups: 'python' }
        
        
#### copy文件
- hosts: web_group
  tasks:
    - name: copy conf and code
      copy:
        src: "{{ item.src }}"
        dest: "{{ item.dest }}"
        mode: "{{ item.mode }}"
      with_items:
        - { src: "./httpd.conf", dest: "/etc/httpd/conf/", mode: "0644" }
        - { src: "./upload_file.php", dest: "/var/www/html/", mode: "0600" }