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ansible-变量.md

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+<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
+```
+