5、ansible roles

简介

基于已知的文件结构，自动加载某些vars_files,tasks以及handlers。以便playbook更好的调用。roles相比playbook的结构更加清晰有层次
例如：我们无论安装什么软件都会安装时间同步服务，那么playbook要编写时间同步服务的task，此时我们可以将时间同步服务task任务编写好，等到使用的时候进行调用就可以了
最好在编写roles的时候，最好能将一个task拆分为一个文件，方便后续复用（彻底打散）

练习一：配置memcached

目录结构

实现流程
创建roles的目录结构，手动或使用ansible-galaxy init test
编写roles的功能，也就是tasks
最后playbook引用roles编写好的tasks

操作
ansible-galaxy init test

手动创建配置memcached
mkdir -p memcached/{tasks,handlers,templates}
目录结构（引用文件自动会创建在 memcached 下的memcacheds下的memcached.yml这个案例创建在外面也行）

cd memcached
vim tasks/main.yml

- name: installed memcached server
  yum: name=memcached state=present

- name: configure memcached server
  template: src=memcached.j2 dest=/etc/sysconfig/memcached
  notify:  service memcached restart

- name: started memcached server
  service: name=memcached state=started enabled=yes

vim templates/memcached.j2

PORT="11211"
USER="memcached"
MAXCONN="1024"
CACHESIZE="64"
OPTIONS=""

vim handlers/main.yml

- name: service memcached restart
  service: name=memcached state=restarted

vim ../site.yml

- hosts: webserver
  roles: 
    - memcached

打散方式：
打散后的结构（不建议继续打散）

进入tasks目录
vim install.yml

- name: installed memcached server
  yum: name=memcached state=present

vim configure.yml

- name: configure memcached server
  template: src=memcached.j2 dest=/etc/sysconfig/memcached
  notify: service memcached restart

vim start.yml

- name: started memcached server
  service: name=memcached state=started enabled=yes

引入所有
vim main.yml

- include_tasks: install.yml
- include_tasks: configure.yml
- include_tasks: start.yml

执行结果

最后修改配置文件
vim templates/memcached.j2
然后再次执行检测是否触发restart

练习二：配置nginx+php

cd /root/project/
mkdir {nginx,php}/{tasks,handlers,templates,groupvars} -pv
vim nginx/tasks/main.yml

- name: installed nginx server
  yum: name=nginx state=present

- name: configure nginx server
  template: src=nginx.conf.j2 dest=/etc/nginx/nginx.conf
  notify: service nginx restart

- name: started nginx server
  service: name=nginx state=started enabled=yes

vim nginx/handlers/main.yml

- name: service nginx restart
  service: name=nginx state=restarted

vim nginx/templates/nginx.conf.j2
拷一份nginx配置文件即可
cat /etc/nginx/nginx.conf >nginx/templates/nginx.conf.j2

单独指定启动nginx
vim site.yml

- hosts: webserver
  roles: 
  - role: memcached
    tags: memcached
  - role: nginx
    tags: nginx

ansible-playbook site.yml -t nginx