123 - Nginx高级 - 高可用集群 - 主备Nginx + keepalived

主备Nginx

主Nginx（MASTER）备Nginx（BACKUP）

keepalived
虚拟IP
主Nginx（MASTER）IP
备Nginx（BACKUP）IP

安装keepalived

安装：yum install keepalived -y
测试是否安装成功：rpm -qa keepalived
配置文件：/etc/keepalived/keepalived.conf
日志存放位置：/var/log/messages

keepalived.conf结构

global_defs {
    notification_email {}
}
vrrp_script chk_http_port{}
vrrp_instance VI_1 {
     authentication {}
     virtual_ipaddress {}
}

keepalived.conf - 全局定义部分 global definition

global_defs {
    notification_email {
    acassen@firewall.loc
    failover@firewall.loc
    sysadmin@firewall.loc
}
notification_email_from Alexandre.Cassen@firewall.loc
smtp_server 192.168.200.1
smtp_connect_timeout 30
router_id LVS_DEVEL

router_id LVS_DEVEL
值可以是IP
在/etc/hosts中127.0.0.1 xxx
xxx就是这个id

keepalived.conf - 检测脚本 vrrp_script chk_http_port

vrrp_script chk_http_port{
        script "/user/local/src/nginx_check.sh"
        interval 2
        weight 2
}

script 脚本地址
interval 2 脚本检测时间，2秒
weight 权重改变，当脚本中的条件成立，当前服务器权重-20

keepalived.conf - 虚拟IP vrrp_instance - 主MASTER

 vrrp_instance VI_1 {
     state MASTER
     interface eth0
     virtual_router_id 51
     priority 100
     advert_int 1
     authentication {
         auth_type PASS
         auth_pass 1111
     }
     virtual_ipaddress {
         192.168.200.16
         192.168.200.17
         192.168.200.18
     }
 }

state MASTER/BACKUP 主设备MASTER还是备设备BACKUP

interface ens33 网卡号
终端：ifconfig
第一行第一个英文单词

virtual_router_id 51 主设备和备设备id要相同

priority 100 优先级，主机值大，备机值小

advert_int 1 每隔一秒测试有没有活着

authentication 权限调用方式

virtual_ipaddress 虚拟IP地址

keepalived.conf - 虚拟IP vrrp_instance - 备BACKUP

 vrrp_instance VI_1 {
     state BACKUP
     interface eth0
     virtual_router_id 51
     priority 90
     advert_int 1
     authentication {
         auth_type PASS
         auth_pass 1111
     }
     virtual_ipaddress {
         192.168.200.16
         192.168.200.17
         192.168.200.18
     }
 }

state MASTER/BACKUP 主设备MASTER还是备设备BACKUP

interface ens33 网卡号
终端：ifconfig
第一行第一个英文单词

virtual_router_id 51 主设备和备设备id要相同

priority 100 优先级，主机值大，备机值小

advert_int 1 每隔一秒测试有没有活着

authentication 权限调用方式

virtual_ipaddress 虚拟IP地址

nginx_check.sh

/user/local/src/nginx_check.sh

#!/bin/bash
A=`ps -C nginx –no-header |wc -l`
if [ $A -eq 0 ];then
    /usr/local/nginx/sbin/nginx
    sleep 2
    if [ `ps -C nginx --no-header |wc -l` -eq 0 ];then
        killall keepalived
    fi
fi

主备都启动Nginx

主备都启动keepalived

systemctl start keepalived.service

ps -ef | grep keepalived