<h2><center> Ansible变量 </center></h2>

------

## 一：变量

### 1. 语法格式

```shell
变量调用语法：
{{ var_name }}
```

### 2. 案例一

​	通过命令行传递变量：（通过--extra-vars或-e选项来传递key=value变量）

```bash
[root@ansible-server ~]# ansible-playbook release.yml -e "user=starbuck"
```

​	传递字典：

```bash
[root@ansible-server ~]# ansible-playbook conf.yml  -e '{"conf81":"/root/81.conf","conf82":"/root/conf82"}'
```



### 3.案例二

​	创建变量目录

```bash
[root@ansible-server ~]# mkdir /etc/ansible/vars
[root@ansible-server ~]# cd /etc/ansible/vars/
```

​	创建变量文件

```bash
[root@ansible-server vars]# vim file.yml
src_path: /root/test/a.txt
dest_path: /opt/test/
```

​	创建一个测试文件

```bash
[root@ansible-server vars]# mkdir /root/test
[root@ansible-server vars]# echo 123 >/root/test/a.txt
```

​	创建playbook引用变量文件

```bash
[root@ansible-server vars]# cd /etc/ansible/
[root@ansible-server ansible]# vim vars.yml
- hosts: ansible-web1
  user: root
  vars_files:
   - /etc/ansible/vars/file.yml
  tasks:
   - name: create directory
     file: path={{ dest_path }} mode=755 state=directory
   - name: copy file
     copy: src={{ src_path }} dest={{ dest_path }}
```

​	检测语法：

```bash
[root@ansible-server ansible]# ansible-playbook --syntax-check vars.yml

playbook: vars.yml
```

​	运行剧本：

```bash
[root@ansible-server ansible]# ansible-playbook vars.yml
```



### 4.案例三

​	文件中包含变量

```bash
[root@ansible-server ansible]# vim conf.yml 
- hosts: ansible-web1
  remote_user: root
  vars:
    httpd:
      conf80: /root/80.conf
      conf8080: /root/8080.conf
  tasks:
  - name: task1
    file:
      path: "{{httpd.conf80}}"
      state: touch
  - name: task2
    file:
      path: "{{httpd.conf8080}}"
      state: touch
```

​	检测语法：

```bash
[root@ansible-server ansible]# ansible-playbook --syntax-check conf.yml
```

​	运行剧本:

```BASH
[root@ansible-server ansible]# ansible-playbook conf.yml
```



### 5.案例四

在主机清单中定义变量

```bash
[root@ansible-server ansible]# tail -5 /etc/ansible/hosts 
[web]
10.0.0.111
[web:vars]
conf81=ppp
conf82=ooo
```

创建剧本

```bash
[root@ansible-server ansible]# cat conf.yml 
- hosts: web
  remote_user: root
  tasks:
  - name: task1
    file:
      path: "{{ conf81 }}"
      state: touch
  - name: task2
    file:
      path: "{{ conf82 }}"
      state: touch
```

语法检测

```bash
[root@xingdian ansible]# ansible-playbook --syntax-check conf.yml
```

运行剧本

```bash
[root@xingdian ansible]# ansible-playbook conf.yml
```



### 6.案例五

​	set_fact自定义facts变量

​	set_fact模块可以自定义facts，这些自定义的facts可以通过template或者变量的方式在playbook中使用。如果你想要获取一 个进程使用的内存的百分比，则必须通过set_fact来进行计算之后得出其值，并将其值在playbook中引用

配置mysql innodb buffer size的示例

```yml
 - name: Configure MySQL
   hosts: web
   tasks:
   - name: Calculate InnoDB buffer pool size
     set_fact: innodb_buffer_pool_size_mb="{{ ansible_swapfree_mb / 2 }}"
   - name: nihao
     template: src=/my.cnf dest=/etc/my.cnf owner=root group=root mode=0644 
```

参数说明

```hell
set_fact: innodb_buffer_pool_size_mb="{{ ansible_memtotal_mb / 2 }}"
    通过sey_fact去定义，而不是直接执行   
template: src=templates/my.cnf dest=/etc/my.cnf owner=root group=root mode=0644 
    template：这个是一个模板  可以传变量
```

my.cnf文件

```shell
[mysqld]
datadir=/var/lib/mysql
socket=/var/lib/mysql/mysql.sock
# Disabling symbolic-links is recommended to prevent assorted
security risks
symbolic-links=0
 
# Configure the buffer pool
innodb_buffer_pool_size = {{ innodb_buffer_pool_size_mb|int }}M
[mysqld_safe]
log-error=/var/log/mysqld.log
pid-file=/var/run/mysqld/mysqld.pid
```