playbook是ansible用于配置，部署，和管理被控节点的剧本。通过playbook的“描述”，通过执行“剧本”的
内容，让受控主机达到预期的状态。playbook就像Ansible控制器给被控节点列出的的一系列ad-hoc模块
操作一样，playbook是将该一系列操作组合起来，统一完成操作。
	playbook使用场景
	当一个设施过于复杂，需要大量的操作时候，且需要不断的重复操作，这时最好使用playbook，其使用
意义类似于脚本一样，可以很方便的批处理任务，但playbook与脚本不同的是，playbook有自己的语法
格式。
  1. 单文件剧本示例user_add.yaml 
    # 指定主机组
- hosts: vm
# 用于远程连接的用户名
  remote_user: root
# 不收集主机信息
  gather_facts: no
# 任务列表
  tasks:
	- name: 添加用户
	  user: name=xiaoming state=present
	  tags:
	    - num1
	- name: 添加组
	  group: name=atmgrp state=present
	  tags:
	    - num2
	- name: 复制文件
	  copy: src=/etc/passwd dest=/home
	  tags:
	    - num1
    检查语法
    ansible-playbook --syntax-check user_add.yaml
    预执行
    ansible-playbook -C user_add.yaml
    执行
    ansible-playbook user_add.yaml
    基于标签tags执行
    ansible-playbook -t num1 user_add.yaml
  2. handler触发器示例 
    - hosts: vm
  remote_user: root
  gather_facts: no
  tasks:
	- name: change port
	  command: sed -i 's/Listen 80/Listen 8080/g' /etc/httpd/conf/httpd.conf
	  notify:
		- restart httpd server
  handlers:
	- name: restart httpd server
	  service: name=httpd state=restarted
  3. 基于角色的剧本示例
    在/etc/ansible/roles内创建角色名目录
    mkdir -pv /etc/ansible/roles/mariadb{tasks,handlers,files}
    任务示例/etc/ansible/roles/mariadb/tasks/main.yaml 
    - name: install mariadb
  yum: name=mariadb-server state=present
- name: mv conf file
  shell: "[ -e /etc/my.cnf ] && mv /etc/my.cnf /etc/my.cnf.bak"
- name: cp file
  copy: src=my.cnf dest=/etc/my.cnf
- name: reload mariadb
  shell: "systemctl restart mariadb"
- name: create db
  shell: mysql -u root -e "create database testdb;grant all on testdb.* to 'test'@'192.168.112.%' identified by 'test1234';flush privileges;"
  notify:
	- restart mariadb
    触发示例/etc/ansible/roles/mariadb/handlers/main.yaml 
    - name: restart mariadb
  service: name=mariadb state=restarted
    引用文件示例/etc/ansible/roles/mariadb/files/my.cnf 
    [mysqld]
datadir=/var/lib/mysql
socket=/var/lib/mysql/mysql.sock
# Disabling symbolic-links is recommended to prevent assorted security risks
symbolic-links=0
# Settings user and group are ignored when systemd is used.
# If you need to run mysqld under a different user or group,
# customize your systemd unit file for mariadb according to the
# instructions in http://fedoraproject.org/wiki/Systemd

[mysqld_safe]
log-error=/var/log/mariadb/mariadb.log
pid-file=/var/run/mariadb/mariadb.pid

#
# include all files from the config directory
#
!includedir /etc/my.cnf.d
    主剧本示例install_mariadb.yaml 
    - hosts: vm
  remote_user: root
  gather_facts: no
  roles:
	- mariadb
    检查语法
    ansible-playbook --syntax-check install_mariadb.yaml
    预执行
    ansible-playbook -C install_mariadb.yaml
    执行
    ansible-playbook install_mariadb.yaml

实例