Ansible之Playbook详解

1.Playbook详解

playbook是一个非常简单的配置管理和多主机部署系统,可以定制配置,可以按照指定的操作步骤有序执行,支持同步和异步方式.

核心元素

Hosts:主机

Tasks:任务,由模板定义的操作列表

Variables:变量

Templates:模板,即使用模板语法的文件

Handlers:处理器,当某条件满足时,触发执行的操作

Roles:角色

cat test.yaml
- hosts: all
  remote_user: root
  tasks:
  - name: install redis
    yum: name=redis state=latest
  - name: copy config file
    copy: src=/root/playbook/redis.conf dest=/etc/redis.conf owner=redis
    notify: restart redis
    tags: ChangeConfigFile
  - name: start redis
    service: name=redis state=started
  handlers:
  - name: restart redis
    service: name=redis state=restarted
# 检查yaml文件的语法是否正确
ansible-playbook test.yaml --syntax-check
# 检查tasks任务
ansible-playbook test.yaml --list-task
# 检查生效的主机
ansible-playbook test.yaml --list-hosts
# 干跑一遍
ansible-playbook -C test.yaml
# 指定从某个task开始运行
ansible-playbook test.yaml --start-at-task='Copy Nginx.conf'
ansible-playbook test.yaml -t ChangeConfigFile

Handlers:如果触发了指定条件,则notify就会通知handlers执行对应操作.

2.引入变量

# 引用变量,收集主机facts变量
ansible-doc -s setup
ansible 10.0.0.51 -m setup
直接引用Ansible变量
- hosts: all
  remote_user: root
  tasks:
  - name: copy file
    copy: content={{ ansible_env }} dest=/opt/ansibel_env.txt
自定义变量
- hosts: all
  remote_user: root
  tasks:
  - name: install package {{ pkgname }}
    yum: name={{ pkgname }} state=latest

ansible-playbook -e pkgname=memcache -C forth.yaml
引用主机变量,在组的主机后面添加变量
[webservers]
10.0.0.51 ansibel_ssh_port=9122 ansibel_ssh_user=lixiang ansibel_ssh_pass=lixiang
10.0.0.52
第二种方式
[webservers:vars]
http_port=8080

三种调用方式示例
- hosts: webservers
  remote_user: root
  vars:
  - pbvar: playbook Var test
  tasks:
  - name: command line var
    copy: content={{ cmdvar }} dest=/tmp/cmd.var
  - name: playbook var
    copy: content={{ pbvar }} dest=/tmp/pb.var
  - name: host iventory var
    copy: content={{ http_port }} dest=/tmp/host.var
# cmdvar传值,中间有空格,会不识别
ansible-playbook -e cmdvar="command line var" vars.yaml

3.Templates介绍

# redis.conf.j2这个文件是从一个redis文件拷贝而来,修改了bind这一行
head /root/playbook/redis.conf.j2
bind {{ ansibel_eth0.ipv4.address4}}
cat templete.yaml
- hosts: webservers
  remote_user: root
  tasks:
  - name: templete config file
  templete: src=/root/playbook/redis.conf.j2 dest=/tmp/redis.conf

4.条件判断

条件测试-when语句:
tasks:
- name: install conf file to centos7
  templete: src=/path/nginx.conf.c7.j2 dest=/etc/nginx/conf.d/nginx.conf
  when: ansible_distribution_major_version == "7"
- name: install conf file to centos6
  templete: src=/path/nginx.conf.c6.j2 dest=/etc/nginx/conf.d/nginx.conf
  when: ansible_distribution_major_version == "6"

多条件判断
tasks:
- name: install conf file to centos7
  templete: src=/path/nginx.conf.c7.j2 dest=/etc/nginx/conf.d/nginx.conf
  when:
  - ansible_distribution == "CentOS"
  - ansible_distribution_major_version == "7"
组合条件判断
tasks:
- name: install conf file to centos7
  templete: src=/path/nginx.conf.c7.j2 dest=/etc/nginx/conf.d/nginx.conf
  when: (ansible_distribution == "CentOS" and ansible_distribution_major_version == "7" ) or
        (ansible_distribution == "RedHat" and ansible_distribution_major_version == "7" )

迭代:有需要循环执行任务时,可以使用迭代机制
cat iter.yaml
- hosts: webservers
  remote_user: root
  tasks:
  - name: install {{ item }} package
  yum: name={{ item }} state=latest
  with_item:
  - nginx
  - tomcat
  - mariadb-server
  - redis

5.角色(roles)

每个角色,以特定的层级目录结构进行组织.

mysql/

files/:存放由copy或script等模块调用的文件;

templetes/:templete模块查找所需要模板文件的目录;

tasks/:至少应该包含一个名为main.yml的文件,其它的文件需要在此文件中通过include进行包含;

handlers/:至少应该包含一个名为main.yml的文件,其它的文件需要在此文件中通过include进行包含;

vars/:至少应该包含一个名为main.yml的文件,其它的文件需要在此文件中通过include进行包含;

meta/:至少应该包含一个名为main.yml的文件,定义当前角色的特殊设定及其依赖关系,其它的文件需要在此文件中通过include进行包含;

default/:设定默认变量时使用此目录中的main.yaml文件.

# 配置文件中指定了roles路径
roles_path=/etc/ansible/roles
mkdir -pv /etc/ansible/roles/nginx/{files,templetes,tasks,vars,handlers,meta,default}
cat /etc/ansible/roles/nginx/tasks/main.yml
- name: install nginx
  yum: name=nginx state=latest
  when: ansible_os_family == "RedHat"
- name: install conf
  templete: src=vhost1.conf.j2 dest=/etc/nginx/conf.d/vhost1.conf
  tags: conf
  notify: restart nginx
- name: create site home-directory
  file: path={{ ngxhomedir }} state=directory
- name: create index page
  copy: src=index.html dest={{ ngxhomedir }}/
- name: start nginx
  service: name=nginx state=started

# 定义变量时,不用加横线
cat /etc/ansible/roles/nginx/vars/main.yml
ngxhomedir: /ngxdata/vhost1

cat /etc/ansible/roles/nginx/files/index.yml
<h1>Vhost1</h1>

cat /etc/ansible/roles/nginx/handlers/main.yml
- name: restart nginx
  service: name=nginx state=restarted

cat nginx.yml
- hosts: webservers
  remote_user: root
  roles:
  - nginx

cat /etc/ansible/roles/nginx/templetes/vhost1.conf.j2
server{
        listen 8080;
        server_name {{ ansibel_fqdn}};
        location / {
                 root "/ngxdata/vhost1";
        }
}

参考博客:https://blog.51cto.com/13630803/2154192