Jinja2模板概述

例子一

循环语句

[root@m01 ~]# cat upstream.conf 
upstream web {
        {% for i in range(1,11) %}
           server 172.16.1.{{ i }}
        {% endfor %}
}

server {
	listen 80;
	server_name wp.gong.com;
        location / {
                proxy_pass http://web;
                include proxy_params;
        }
}

[root@m01 ~]# cat send_conf.yml 
- hosts: web01
  tasks:
    - name: send jianja mode
      template:
        src: /root/upstream.conf
        dest: /root/upstream.conf



# 推送生成的效果
[root@web01 ~]# cat upstream.conf 
upstream web {
                   server 172.16.1.1
                   server 172.16.1.2
                   server 172.16.1.3
                   server 172.16.1.4
                   server 172.16.1.5
                   server 172.16.1.6
                   server 172.16.1.7
                   server 172.16.1.8
                   server 172.16.1.9
                   server 172.16.1.10
        }
server {
	listen 80;
	server_name wp.gong.com;
        location / {
                proxy_pass http://web;
                include proxy_params;
        }
}

jinjia2语法

变量

## 调用变量
{{ VAR }}		# 会把里面的变量名转换为变量值

## 模版文件
在一个文件中有{{ vars }}去调用变量的，使用template复制，会把变量转换为值。
模版文件中可以调用自己设置的变量。str_www: www
{{ str_www }}

调用facts变量
{{ ansible_fqdn }}  # 获取主机名
{{ ansible_memtotal_mb }}	# 获取主机物理内存大小

## 逻辑判断语法
- 注释
  {# 中间的是注释 #}
在推送的时候，注释不会推送到目标主机

- 循环
  ｛% for var in data %｝
      {{ var }}					# 表示调用变量名，data可以是一个可迭代对象
  ｛% endfor %｝
  
 - 判断的语法
    {% if ansible_fqdn == "db01" %}
        mem=16G
    {% elif ansible_fqdn == "db02" %}
        mem=8G
    {% else %}
        mem=4G
    {% endif %}

案例一

推送motd

[root@m01 ~]# cat motd.j2 
本机内存：{{ ansible_memtotal_mb }}
剩余内存：{{ ansible_memfree_mb }}
ip add : {{ ansible_eth0.ipv4.address }}

[root@m01 ~]# cat send_motd.yml 
- hosts: web01
  tasks:
    - name: send jianja mode
      template:
        src: /root/motd.j2
        dest: /root/motd
        
[root@web01 ~]# cat motd 
本机内存：456
剩余内存：9
ip add : 10.0.0.7

fqdn和hostname的区别: 比如主机名是www.baidu.com;使用ansible_hostname得到的变量值是www；ansible_fqdn 取到的值是www.baidu.com

案例二

通过判断来配置不同的域名的nignx配置文件

[root@m01 ~]# cat upstream.j2 
upstream web {
        {% for i in range(1,10) %}
           server 172.16.1.{{ i }}
        {% endfor %}
}

server {
	listen 80;
        {% if ansible_fqdn == "web01" %}
        	server_name {{ domain_1 }}
      
        {% elif ansible_fqdn == "web02" %}
        	server_name {{ domain_2 }}
        
        {% elif ansible_fqdn == "web03" %}
        	server_name {{ domain_3 }}
        {% endif %}
        location / {
                proxy_pass http://web;
                include proxy_params;
        }
}

[root@m01 ~]# cat send_up_j2.yml 
- hosts: web_group
  vars:
    - domain_1: www.baidu.com
    - domain_2: www.google.com
    - domain_3: gong.cc.con
  tasks:
    - name: send up_j2 mode
      template:
        src: /root/upstream.j2
        dest: /root/upstream_j2.conf

[root@web01 ~]# cat upstream_j2.conf 
upstream web {
                   server 172.16.1.1
                   server 172.16.1.2
                   server 172.16.1.3
                   server 172.16.1.4
                   server 172.16.1.5
                   server 172.16.1.6
                   server 172.16.1.7
                   server 172.16.1.8
                   server 172.16.1.9
        }

server {
	listen 80;
                	server_name www.baidu.com
      
                location / {
                proxy_pass http://web;
                include proxy_params;
        }
}

[root@web02 ~]# cat upstream_j2.conf 
upstream web {
                   server 172.16.1.1
                   server 172.16.1.2
                   server 172.16.1.3
                   server 172.16.1.4
                   server 172.16.1.5
                   server 172.16.1.6
                   server 172.16.1.7
                   server 172.16.1.8
                   server 172.16.1.9
        }

server {
	listen 80;
                	server_name www.google.com
        
                location / {
                proxy_pass http://web;
                include proxy_params;
        }
}

案例三

管理keepalived的配置文件

判断语法

[root@lb01 ~]# cat /etc/keepalived/keepalived.conf 
global_defs { 
    router_id lb01
}

vrrp_script check_web {
    script "/root/check_web.sh"
    interval 5

vrrp_instance VI_1 {
    state MASTER   
    interface eth0
    virtual_router_id 50
    priority 150
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {                
        10.0.0.3
    }
    track_script {
        check_web
    }   
}



[root@lb02 ~]# cat /etc/keepalived/keepalived.conf 
global_defs {
    router_id lb02
}

vrrp_instance VI_1 {
    state BACKUP
    interface eth0
    virtual_router_id 50
    priority 100
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        10.0.0.3
    }
}


[root@lb01 ~]# cat /etc/keepalived/keepalived.conf 
global_defs { 
    router_id lb01
}

vrrp_script check_web {
    script "/root/check_web.sh"
    interval 5

vrrp_instance VI_1 {
    state MASTER   
    interface eth0
    virtual_router_id 50
    priority 150
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {                
        10.0.0.3
    }
    track_script {
        check_web
    }   
}


{# 把keepalived配置文件改成模板文件 #}
global_defs {
    router_id {{ ansible_fqdn }}
}

vrrp_instance VI_1 {
	{% if ansible_fqdn == 'lb01' %}
    state MASTER
    priority 150
    {% elif ansible_fqdn == 'lb02' %}
    state BACKUP
    priority 100
    {% endif %}
    interface eth0
    virtual_router_id 50
    advert_int 1
    authentication {
        auth_type PASS  
        auth_pass 1111
    }
    virtual_ipaddress {
        10.0.0.3
    }
}

案例四

根据实际物理内存的大小来分配给mysql所占内存的百分比

[root@m01 ~]# vi mysql_mem.j2
[mysqld]
datadir=/var/lib/mysql
socket=/var/lib/mysql/mysql.sock
innodb_buffer_pool_size = {{ (ansible_memtotal_mb * 0.8) | int }}
symbolic-links=0

[mysqld_safe]
log-error=/var/log/mariadb/mariadb.log
pid-file=/var/run/mariadb/mariadb.pid

!includedir /etc/my.cnf.d

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