一，jinja2

1.概述

Jinja2 是一个现代的，设计者友好的，模板语言。 它速度快，被广泛使用，并且提供了可选的沙箱模板执行环境保证安全。

当利用jinja2进行渲染的时候，它会把这些特殊的占位符进行填充/替换，jinja2支持python中所有的Python数据类型比如列表、字段、对象等。

2.Ansible 如何使用 jinja2 模板

Ansible 使用 jinja2 模板，也就是 template 模板。该模块和 copy 模块一样，都是将文件复制到目标机器，但是区别在于 template 模块可以获取要复制文件中的变量的值，而 copy 则是原封不动的把文件内容复制过去。

比如：针对不同的主机定义不同的变量，template 会在将文件分发前读取变量到 jinja2 模板，之后再然后分发到不同的被管理主机上。

3.jinja2渲染NginxProxy配置文件用到的语法三种语法

控制结构 {% %} 变量取值 {{ }} 注释 {# #}。

二，演示

1 变量中的循环语句 案例：nginx proxy
2 变量中的判断语法 案例：keeplive不同主机的配置
3 Inventory方式实现 案例：keeplive不同主机的配置
**4. jinja变量方式实现 案例：keeplive不同主机的配置

1. 变量中的循环语句

给10台主机装上Nginx服务，但是要求每台主机的端口都不一样，如何解决？

（ jinja配置文件模板，根据不同主机生成不同文件配置nginx proxy）

主机清单：

[root@manager ansible_roles]# cat proxy_blog.oldxu.com.conf.j2

  1. upstream {{ blog_site }} {
  2.  {% for host in groups['webservers'] %}
  3.     server {{ host }};
  4. {% endfor %}
  6. server {
  7.     listen 80;
  8.     server_name localhost;
  10.     location / {
  11.         proxy_pass http://{{ blog_site }};
  12.         include proxy_params;
  13.     }
  14. }

playbook —- 将nginx.conf文件批量拷到对端
[root@manager ansible_roles]# cat nginx_proxy.yml

  1. - hosts: webservers
  2.   vars:
  3.     - blog_site: blog.oldxu.com
  4.   tasks:
  5.     - name: Configure Nginx Proxy Vurtual File
  6.       template:
  7.         src: ./proxy_blog.oldxu.com.conf.j2
  8.         dest: /tmp/proxy_blog.oldxu.com.conf

2. 使用判断语法推送不同文件

常规写法：首先需要写好两个不同配置的文件，再判断不同主机推送不同配置（太笨重）
[root@manager ansible_roles]# cat keepalived.yml #keepalive的安装，配置，启动

  1. - hosts: lbservers
  2.   tasks:
  3.     - name: Install Keepalived Server
  4.       yum:
  5.         name: keepalived
  6.         state: present
  8.     - name: Configure Keepalived Server
  9.       copy:
  10.         src: ./keepalived-master.conf.j2
  11.         dest: /etc/keepalived/keepalived.conf
  12.       when: ( ansible_hostname == "lb01" )
  13.       notify: Restart Keepalived Server
  15.     - name: Configure Keepalived Server
  16.       copy:
  17.         src: ./keepalived-backup.conf.j2
  18.         dest: /etc/keepalived/keepalived.conf
  19.       when: ( ansible_hostname == "lb02" )
  20.       notify: Restart Keepalived Server
  23.     - name: Started Keepalived Server
  24.       systemd:
  25.         name: keepalived
  26.         state: started
  27.         enabled: yes
  29.   handlers:
  30.     - name: Restart Keepalived Server
  31.       systemd:
  32.         name: keepalived
  33.         state: restarted

3. 使用inventory 方式来生成不同配置文件

主机清单 　　　　　#预先定义好变量

  1. hosts:
  2. [lbservers]
  3. 172.16.1.5 state=MASTER priority=150
  4. 172.16.1.6 state=BACKUP priority=120

[root@manager ansible_roles]# cat keepalived-template.conf.j2 #keepalvie配置文件

  1. global_defs {
  2.     router_id {{ ansible_hostname }}
  3. }
  5. vrrp_instance VI_1 {
  6.     state {{ state }}
  7.     priority {{ priority }}
  9.     interface eth0
  10.     virtual_router_id 50
  11.     advert_int 1
  12.     authentication {
  13.         auth_type PASS
  14.         auth_pass 1111
  15. }
  16.     virtual_ipaddress {
  17.         10.0.0.3
  18.     }
  19. }

[root@manager ansible_roles]# cat keepalived.yml 　#keepalive的安装，配置，启动

  1. - hosts: lbservers
  2.   tasks:
  3.     - name: Install Keepalived Server
  4.       yum:
  5.         name: keepalived
  6.         state: present
  8.     - name: Configure Keepalived Server
  9.       template:
  10.         src: keepalived-template.conf.j2
  11.         dest: /etc/keepalived/keepalived.conf
  12.       notify: Restart Keepalived Server
  14.     - name: Started Keepalived Server
  15.       systemd:
  16.         name: keepalived
  17.         state: started
  18.         enabled: yes
  20.   handlers:
  21.     - name: Restart Keepalived Server
  22.       systemd:
  23.         name: keepalived
  24.         state: restarted

*4. 使用 jinja方式来生成不同文件(if，变量)

主机清单
[root@manager ansible_roles]# cat hosts

  1. [lbservers]
  2. 172.16.1.5
  3. 172.16.1.6

[root@manager ansible_roles]# cat keepalived-template.conf.j2　＃keepalive配置的 jinja2文件

  1. global_defs {
  2.     router_id {{ ansible_hostname }}
  3. }
  5. vrrp_instance VI_1 {
  6. {% if ansible_hostname == "lb01" %}
  7.     state MASTER
  8.     priority 200
  9. {% elif ansible_hostname == "lb02" %}
  10.     state BACKUP
  11.     priority 100
  12. {% endif %}
  13.     interface eth0
  14.     virtual_router_id 50
  15.     advert_int 1
  16.     authentication {
  17.         auth_type PASS
  18.         auth_pass 1111
  19. }
  20.     virtual_ipaddress {
  21.         10.0.0.3
  22.     }
  23. }

[root@manager ansible_roles]# cat keepalived.yml #keepalive的安装，配置，启动

  1. - hosts: lbservers
  2.   tasks:
  3.     - name: Install Keepalived Server
  4.       yum:
  5.         name: keepalived
  6.         state: present
  8.     - name: Configure Keepalived Server
  9.       template:
  10.         src: keepalived-template.conf.j2
  11.         dest: /etc/keepalived/keepalived.conf
  12.       notify: Restart Keepalived Server
  14.     - name: Started Keepalived Server
  15.       systemd:
  16.         name: keepalived
  17.         state: started
  18.         enabled: yes
  20.   handlers:
  21.     - name: Restart Keepalived Server
  22.       systemd:
  23.         name: keepalived
  24.         state: restarted