Ansible-playbook的变量和引用

1、通过Inventory文件定义主机和主机组变量

 Ansible默认的Inventory文件是INI格式。直接开始测试，先看定义的host文件：

[root@zero01 inventory]# cat host_playbook 
192.168.79.129 key=129 
192.168.79.130 key=130
192.168.79.131 key=131
192.168.79.132 key=132
[nginx]
192.168.79.1[29:32]
[nginx:vars]
ansible_python_interpreter=/usr/bin/python2.6

 接下来，编写一个playbook文件验证变量的引用是否正确，内容如下：

[root@zero01 playbook]# cat variable.yaml 
---
- hosts: all
  gather_facts: False
  tasks:
    - name: diplay Host Variable from hostfile
      debug: msg="The {{ inventory_hostname }} Value is {{ key }}"

 运行playbook（不指定绝对路径要在playbook文件下运行），如下所示：

[root@zero01 playbook]# ansible-playbook variable.yaml

PLAY [all] *******************************************************************************************************************

TASK [diplay Host Variable from hostfile] *******************************************************************************************************************
ok: [192.168.79.129] => {
    "msg": "The 192.168.79.129 Value is 129"
}
ok: [192.168.79.130] => {
    "msg": "The 192.168.79.130 Value is 130"
}
ok: [192.168.79.131] => {
    "msg": "The 192.168.79.131 Value is 131"
}
ok: [192.168.79.132] => {
    "msg": "The 192.168.79.132 Value is 132"
}

PLAY RECAP *******************************************************************************************************************
192.168.79.129             : ok=1    changed=0    unreachable=0    failed=0   
192.168.79.130             : ok=1    changed=0    unreachable=0    failed=0   
192.168.79.131             : ok=1    changed=0    unreachable=0    failed=0   
192.168.79.132             : ok=1    changed=0    unreachable=0    failed=0   

 可以看到，每台主机都引用了自己的主机变量key；下面开始测试主机组变量，先注释掉每台主机的变量定义，再给nginx组定义一个主机组变量，变量名为key且值为zero_gg（此处如果要修改变量名，要对应修改playbook），如下所示：

[root@zero01 inventory]# cat host_playbook 
#192.168.79.129 key=129 
#192.168.79.130 key=130
#192.168.79.131 key=131
#192.168.79.132 key=132
[nginx]
192.168.79.1[29:32]
[nginx:vars]
ansible_python_interpreter=/usr/bin/python2.6
key=zero_gg

 运行playbook文件：

[root@zero01 playbook]# ansible-playbook variable.yaml 

PLAY [all] *******************************************************************************************************************

TASK [diplay Host Variable from hostfile] *******************************************************************************************************************
ok: [192.168.79.129] => {
    "msg": "The 192.168.79.129 Value is zero_gg"
}
ok: [192.168.79.130] => {
    "msg": "The 192.168.79.130 Value is zero_gg"
}
ok: [192.168.79.131] => {
    "msg": "The 192.168.79.131 Value is zero_gg"
}
ok: [192.168.79.132] => {
    "msg": "The 192.168.79.132 Value is zero_gg"
}

PLAY RECAP *******************************************************************************************************************
192.168.79.129             : ok=1    changed=0    unreachable=0    failed=0   
192.168.79.130             : ok=1    changed=0    unreachable=0    failed=0   
192.168.79.131             : ok=1    changed=0    unreachable=0    failed=0   
192.168.79.132             : ok=1    changed=0    unreachable=0    failed=0  

 可以看到，主机组变量针对组内所有的主机都生效。注意：如果主机同时定义了主机变量和主机组变量，名字相同时，主机变量生效，主机组变量不生效；名字不同时，都可以调用。

2、通过/etc/ansible/下的文件定义主机和主机组变量

 使用yum安装Ansible默认配置文件是在/etc/ansible/目录下，可在该目录下，创建文件夹host_vars定义主机变量，创建group_vars定义主机组变量（此情况要求yaml文件不再/etc/ansible/的子目录下）；如果采用其他的安装方式，在playbook文件当前目录下创建两个目录即可。如下：

[root@zero01 ansible]# tree
.
├── ansible.cfg
├── hosts
├── inventory
│   ├── host
│   └── host_playbook
├── playbook
│   ├── group_vars
│   │   └── nginx
│   ├── host_vars
│   │   ├── 192.168.79.129
│   │   ├── 192.168.79.130
│   │   ├── 192.168.79.131
│   │   └── 192.168.79.132
│   ├── nginx.yaml
│   ├── tasks
│   │   └── main.yaml
│   ├── variable.retry
│   └── variable.yaml
└── roles

[root@zero01 inventory]# cat host
192.168.79.129
192.168.79.130
192.168.79.131
192.168.79.132 
[nginx]
192.168.79.1[29:32]

 分别在group_vars、host_vars下创建主机组变量文件和主机变量文件，内容如下：

[root@zero01 ansible]# cat group_vars/nginx
---
key: zero_gg

[root@zero01 ansible]# head host_vars/*
==> host_vars/192.168.79.129 <==
---
key: 192.168.79.129

==> host_vars/192.168.79.130 <==
---
key: 192.168.79.130

==> host_vars/192.168.79.131 <==
---
key: 192.168.79.131

==> host_vars/192.168.79.132 <==
---
key: 192.168.79.132

 运行playbook文件，结果如下：

[root@zero01 playbook]# ansible-playbook variable.yaml 

PLAY [all] *******************************************************************************************************************

TASK [diplay Host Variable from hostfile] *******************************************************************************************************************
ok: [192.168.79.129] => {
    "msg": "The 192.168.79.129 Value is 192.168.79.129"
}
ok: [192.168.79.130] => {
    "msg": "The 192.168.79.130 Value is 192.168.79.130"
}
ok: [192.168.79.131] => {
    "msg": "The 192.168.79.131 Value is 192.168.79.131"
}
ok: [192.168.79.132] => {
    "msg": "The 192.168.79.132 Value is 192.168.79.132"
}

PLAY RECAP *******************************************************************************************************************
192.168.79.129             : ok=1    changed=0    unreachable=0    failed=0   
192.168.79.130             : ok=1    changed=0    unreachable=0    failed=0   
192.168.79.131             : ok=1    changed=0    unreachable=0    failed=0   
192.168.79.132             : ok=1    changed=0    unreachable=0    failed=0   

 由上可验证，当主机变量和主机组变量同时存在且名字相同时，只有主机变量生效，主机组变量不生效；

 下面验证group_vars/下的nginx组的主机组变量，如下：

[root@zero01 playbook]# rm -rf host_vars/*
[root@zero01 playbook]# ansible-playbook variable.yaml 

PLAY [all] *******************************************************************************************************************

TASK [diplay Host Variable from hostfile] *******************************************************************************************************************
ok: [192.168.79.129] => {
    "msg": "The 192.168.79.129 Value is zero_gg"
}
ok: [192.168.79.130] => {
    "msg": "The 192.168.79.130 Value is zero_gg"
}
ok: [192.168.79.131] => {
    "msg": "The 192.168.79.131 Value is zero_gg"
}
ok: [192.168.79.132] => {
    "msg": "The 192.168.79.132 Value is zero_gg"
}

PLAY RECAP *******************************************************************************************************************
192.168.79.129             : ok=1    changed=0    unreachable=0    failed=0   
192.168.79.130             : ok=1    changed=0    unreachable=0    failed=0   
192.168.79.131             : ok=1    changed=0    unreachable=0    failed=0   
192.168.79.132             : ok=1    changed=0    unreachable=0    failed=0  

3、通过ansible-playbook命令行传入

 通过ansible-playbook命令行传参的方式定义变量，默认传进去的都是全局变量，如下：

[root@zero01 playbook]# ansible-playbook variable.yaml -e "key=ZERO"

PLAY [all] *******************************************************************************************************************

TASK [diplay Host Variable from hostfile] *******************************************************************************************************************
ok: [192.168.79.129] => {
    "msg": "The 192.168.79.129 Value is ZERO"
}
ok: [192.168.79.130] => {
    "msg": "The 192.168.79.130 Value is ZERO"
}
ok: [192.168.79.131] => {
    "msg": "The 192.168.79.131 Value is ZERO"
}
ok: [192.168.79.132] => {
    "msg": "The 192.168.79.132 Value is ZERO"
}

PLAY RECAP *******************************************************************************************************************
192.168.79.129             : ok=1    changed=0    unreachable=0    failed=0   
192.168.79.130             : ok=1    changed=0    unreachable=0    failed=0   
192.168.79.131             : ok=1    changed=0    unreachable=0    failed=0   
192.168.79.132             : ok=1    changed=0    unreachable=0    failed=0  

 这种方式同时支持传入多个变量，还支持指定文件的方式传入变量，变量的文件内容支持两种格式：YAML和JSON

 YAML:

[root@zero01 tmp]# cat var.yaml 
---
key: YAML

[root@zero01 playbook]# ansible-playbook variable.yaml -e "@/tmp/var.yaml"

PLAY [all] *******************************************************************************************************************

TASK [diplay Host Variable from hostfile] *******************************************************************************************************************
ok: [192.168.79.129] => {
    "msg": "The 192.168.79.129 Value is YAML"
}
ok: [192.168.79.130] => {
    "msg": "The 192.168.79.130 Value is YAML"
}
ok: [192.168.79.131] => {
    "msg": "The 192.168.79.131 Value is YAML"
}
ok: [192.168.79.132] => {
    "msg": "The 192.168.79.132 Value is YAML"
}

PLAY RECAP *******************************************************************************************************************
192.168.79.129             : ok=1    changed=0    unreachable=0    failed=0   
192.168.79.130             : ok=1    changed=0    unreachable=0    failed=0   
192.168.79.131             : ok=1    changed=0    unreachable=0    failed=0   
192.168.79.132             : ok=1    changed=0    unreachable=0    failed=0  

 JSON:

[root@zero01 tmp]# cat var.json 
{"key": "JSON"}

[root@zero01 playbook]# ansible-playbook variable.yaml -e "@/tmp/var.json"

PLAY [all] *******************************************************************************************************************

TASK [diplay Host Variable from hostfile] *******************************************************************************************************************
ok: [192.168.79.129] => {
    "msg": "The 192.168.79.129 Value is JSON"
}
ok: [192.168.79.130] => {
    "msg": "The 192.168.79.130 Value is JSON"
}
ok: [192.168.79.131] => {
    "msg": "The 192.168.79.131 Value is JSON"
}
ok: [192.168.79.132] => {
    "msg": "The 192.168.79.132 Value is JSON"
}

PLAY RECAP *******************************************************************************************************************
192.168.79.129             : ok=1    changed=0    unreachable=0    failed=0   
192.168.79.130             : ok=1    changed=0    unreachable=0    failed=0   
192.168.79.131             : ok=1    changed=0    unreachable=0    failed=0   
192.168.79.132             : ok=1    changed=0    unreachable=0    failed=0  

4、在playbook文件内使用vars

[root@zero01 playbook]# vi variable.yaml 
---
- hosts: all
  gather_facts: False
  vars:
     key: Ansible
  tasks:
    - name: diplay Host Variable from hostfile
      debug: msg="The {{ inventory_hostname }} Value is {{ key }}"

 直接运行，如下：

[root@zero01 playbook]# ansible-playbook variable.yaml

PLAY [all] *******************************************************************************************************************

TASK [diplay Host Variable from hostfile] *******************************************************************************************************************
ok: [192.168.79.129] => {
    "msg": "The 192.168.79.129 Value is Ansible"
}
ok: [192.168.79.130] => {
    "msg": "The 192.168.79.130 Value is Ansible"
}
ok: [192.168.79.131] => {
    "msg": "The 192.168.79.131 Value is Ansible"
}
ok: [192.168.79.132] => {
    "msg": "The 192.168.79.132 Value is Ansible"
}

PLAY RECAP *******************************************************************************************************************
192.168.79.129             : ok=1    changed=0    unreachable=0    failed=0   
192.168.79.130             : ok=1    changed=0    unreachable=0    failed=0   
192.168.79.131             : ok=1    changed=0    unreachable=0    failed=0   
192.168.79.132             : ok=1    changed=0    unreachable=0    failed=0   

 如上，playbook文件中定义的变量对所有主机都有效，可理解为主机组变量。

5、在playbook文件内使用vars_files

[root@zero01 playbook]# cat variable.yaml 
---
- hosts: all
  gather_facts: False
  vars_files:
     - /tmp/var.yaml
  tasks:
    - name: diplay Host Variable from hostfile
      debug: msg="The {{ inventory_hostname }} Value is {{ key }}"

 vars_files默认搜索当前路径，如果文件不在当前目录，需要指出绝对路径。

[root@zero01 playbook]# ansible-playbook variable.yaml 

PLAY [all] *******************************************************************************************************************

TASK [diplay Host Variable from hostfile] *******************************************************************************************************************
ok: [192.168.79.129] => {
    "msg": "The 192.168.79.129 Value is YAML"
}
ok: [192.168.79.130] => {
    "msg": "The 192.168.79.130 Value is YAML"
}
ok: [192.168.79.131] => {
    "msg": "The 192.168.79.131 Value is YAML"
}
ok: [192.168.79.132] => {
    "msg": "The 192.168.79.132 Value is YAML"
}

PLAY RECAP *******************************************************************************************************************
192.168.79.129             : ok=1    changed=0    unreachable=0    failed=0   
192.168.79.130             : ok=1    changed=0    unreachable=0    failed=0   
192.168.79.131             : ok=1    changed=0    unreachable=0    failed=0   
192.168.79.132             : ok=1    changed=0    unreachable=0    failed=0 

6、使用register内的变量

 Ansible playbook内task之间还可以互相传递数据，比如我们总共有两个tasks，其中第2个task是否执行是需要判断第1个task运行后的结果，这个时候我们就得在task之间传递数据，需要把第1个task执行的结果传递给第2个task。

 Ansible task之间传递数据使用register方式

[root@zero01 playbook]# cat register.yaml 
---
  - hosts: all
    gather_facts: False
    tasks:
       - name: register variable
         shell: hostname
         register: info
       - name: display variable
         debug: msg="The variable is {{ info }}"

 这里把第1个task执行hostname的结果register给info这个变量，然后第2个task把这个结果使用debug模板打印出来， 如下：

[root@zero01 playbook]# ansible-playbook register.yaml -l 192.168.79.129

PLAY [all] *******************************************************************************************************************

TASK [register variable] *******************************************************************************************************************
changed: [192.168.79.129]

TASK [display variable] *******************************************************************************************************************
ok: [192.168.79.129] => {
    "msg": "The variable is {'stderr_lines': [], u'changed': True, u'end': u'2017-12-23 17:46:05.777637', 'failed': False, u'stdout': u'zero02', u'cmd': u'hostname', u'rc': 0, u'start': u'2017-12-23 17:46:05.768962', u'stderr': u'', u'delta': u'0:00:00.008675', 'stdout_lines': [u'zero02']}"
}

PLAY RECAP *******************************************************************************************************************
192.168.79.129             : ok=2    changed=1    unreachable=0    failed=0   

info的结果是一段Python字典数据，存储着很多信息，包括执行时间状态变化输出等信息。从字典中，取出想要的值

[root@zero01 playbook]# cat register.yaml 
---
  - hosts: all
    gather_facts: False
    tasks:
       - name: register variable
         shell: hostname
         register: info
       - name: display variable
         debug: msg="The variable is {{ info['stdout'] }}"

 修改register.yaml文件内容，info['stdout']是一个标准的Python语言在字典中取值的用法，执行playbook，如下所示：

[root@zero01 playbook]# ansible-playbook register.yaml -l 192.168.79.129

PLAY [all] *******************************************************************************************************************

TASK [register variable] *******************************************************************************************************************
changed: [192.168.79.129]

TASK [display variable] *******************************************************************************************************************
ok: [192.168.79.129] => {
    "msg": "The variable is zero02"
}

PLAY RECAP *******************************************************************************************************************
192.168.79.129             : ok=2    changed=1    unreachable=0    failed=0  

7、使用vars_prompt传入

 Ansible支持在运行playbook的时，通过交互式的方式给定义好的参数传入参数值，只需在playbook中定义vars_prompt的变量名和交互式提示内容即可。
 Ansible可以对输入的变量值进行加密处理，比如采用SHA512和MD5算法加密。需要注意：如果要对变量值进行加密，ansible机器上要安装passlib python库

[root@zero01 playbook]# cat prompt.yaml 
---
- hosts: all
  gather_facts: False
  vars_prompt:
      - name: "one"
        prompt: "Please input one value"
        private: no
      - name: "two"
        prompt: "Please input two value"
        default: 'good'
        private: yes
  tasks:
      - name: display one value
        debug: msg="one value is {{ one }}"
      - name: display two value
        debug: msg="two value is {{ two }}"

 one为非私有变量，two为私有变量，private的作用是交互模式下是否显示输入的变量值。

[root@zero01 playbook]# ansible-playbook prompt.yaml -l 192.168.79.129
Please input one value: Ansible
Please input two value [good]: 

PLAY [all] *******************************************************************************************************************

TASK [display one value] *******************************************************************************************************************
ok: [192.168.79.129] => {
    "msg": "one value is Ansible"
}

TASK [display two value] *******************************************************************************************************************
ok: [192.168.79.129] => {
    "msg": "two value is zero"
}

PLAY RECAP *******************************************************************************************************************
192.168.79.129             : ok=2    changed=0    unreachable=0    failed=0  

 这里总结了7中常用的定义变量的方式，以及如何去引用。欢迎大家，实践指正，谢谢！

zero_gg：开明睿智，大气谦和...