五：Ansible Roles

五：Ansible Roles

A: Ansible Roles directory structure

1. The official recommended best practices for directory structure defined way

roles/
    common/               # this hierarchy represents a "role"
        tasks/            #
            main.yml      #  <-- tasks file can include smaller files if warranted
        handlers/         #
            main.yml      #  <-- handlers file
        templates/        #  <-- files for use with the template resource
            ntp.conf.j2   #  <------- templates end in .j2
        files/            #
            bar.txt       #  <-- files for use with the copy resource
            foo.sh        #  <-- script files for use with the script resource
        vars/             #
            main.yml      #  <-- variables associated with this role
            
            
#不常用
        defaults/         #
            main.yml      #  <-- default lower priority variables for this role
        meta/             #
            main.yml      #  <-- role dependencies
             library/          # roles can also include custom modules
        module_utils/     # roles can also include custom module_utils
        lookup_plugins/   # or other types of plugins, like lookup in this case

    webtier/              # same kind of structure as "common" was above, done for the webtier role
    monitoring/           # ""
    fooapp/               # ""

2. the Roles to create a directory structure using galaxy

[root@m01 ~]# cd /etc/ansible/roles/

[root@m01 roles]# tree wordpress/
nfs/                #项目名称
├── defaults        #低优先级变量
├── files           #存放文件
├── handlers        #触发器文件
├── meta            #依赖关系文件
├── tasks           #工作任务文件
├── templates       #jinja2模板文件
├── tests           #测试文件
└── vars            #变量文件

Note: You only need these directories, ansible's roles will automatically identify which of main.yml

Two: Ansible Roles Dependencies

rolesIt allows you to automatically introduced into other roles in the use of roles. role-dependent roles in the directory meta / main.yml file relational storage.

For example: push wordpress and unzip, prerequisites, must be installed nginx and php, the service up and running, to run wordpress pages, then we can define nginx and php-dependent roles in the roles of wordpress

[root@m01 roles]# vim /etc/ansible/roles/wordpress/meta/main.yml
dependencies:
  - { role: nginx }
  - { role: php }

If you write a main.yml files in the meta directory, Ansible first execution dependencies automatically file meta directory main.yml file, as shown above, will be executed first nginx and php installation.

如果安装wordpress,main.yml里有nginx和php
流程：
1.当你执行worepress的playbook,会先在meta的main.yml里找nginx
2.找到后，会在roles目录里找nginx，再去nginx目录的meta找依赖，如果无，会在tasks目录里找到安装、配置、启动等
3.装完nginx后再同理执行php
4.最后再执行wordpress的tasks

Three: Ansible Roles Create a directory

ansible-galaxy init service name roles

[root@m01 ~]# cd /etc/ansible/roles/
[root@m01 /etc/ansible/roles]# ansible-galaxy init rsync roles

- rsync was created successfully
  [root@m01 /etc/ansible/roles]# tree 
  .
  └── rsync
    ├── defaults
    │   └── main.yml
    ├── files
    ├── handlers
    │   └── main.yml
    ├── meta
    │   └── main.yml
    ├── README.md
    ├── tasks
    │   └── main.yml
    ├── templates
    ├── tests
    │   ├── inventory
    │   └── test.yml
    └── vars
        └── main.yml

9 directories, 8 files