Nginx+Keepalived 双主配置,nginxkeepalived二、拓扑三、简单原理

Nginx+Keepalived 双主配置,nginxkeepalived二、拓扑三、简单原理

一、架构

在Keepalived + Nginx高可靠负载均衡架构中，keepalived负责实现High-availability (HA) 功能控制前端机VIP(虚拟网络地址)，当有设备发生故障时，热备服务器可以瞬间将VIP自动切换过来，实际运行中体验只有2秒钟切换时间，DNS服务可以负责前端VIP的负载均衡。

二、拓扑

三、简单原理

Nginx-Keepalived-M(nginx主服务器)、Nginx-Keepalived-S（备服务器）两台服务器均通过keepalived软件把eth0网卡绑上一个虚拟IP（VIP1）地址:172.16.1.20，此VIP1当前由谁承载着服务就绑定在谁的eth0上，当Nginx-Keepalived-M发生故障时，Nginx-Keepalived-S会通过/etc/keepalived/keepalived.conf文件中设置的心跳时间advert_int 1检查，无法获取Nginx-Keepalived-M正常状态后瞬间切换到Nginx-Keepalived-S上来实现热双机负载均衡，当Nginx-Keepalived-M恢复后keepalived会通过priority 参数判断优先权将虚拟VIP1地址172.16.1.20重新绑定给Nginx-Keepalived-M的eth0网卡；同理，虚拟IP（VIP2）地址172.16.1.21把先前的Nginx-Keepalived-S当做了主服务器，Nginx-Keepalived-M当成了辅服务器，来实现热双机互备负载均衡。

四、环境

1、Centos6.3 Mini x64 （Nginx-Keepalived-M）IP:172.16.1.22 Vip:172.16.1.20

2、Centos6.3 Mini x64 (Nginx-Keepalived-S) IP:172.16.1.23 Vip:172.16.1.21

五、安装配置

分别在Nginx-Keepalived-M和Nginx-Keepalived-S安装nginx 以及keepalived，安装过程略过。

1、软件安装路径

/usr/local/nginx

/usr/local/keepalived

#cp /usr/local/keepalived/etc/keepalived /etc/keepalived

2、nginx主服务器的keepalived配置

#vi /etc/keepalived/keepalived.conf

——————————————————————-

! Configuration File for keepalived

# written by

ucg.me

global_defs {

router_id Nginx_Id_1

}

vrrp_script chk_nginx {

script “/usr/local/keepalived/etc/check_http.sh” #定义检测脚本

interval 2 #检测间隔

weight 2

}

vrrp_instance Nginx1 { #定义一个实例

state MASTER #定义为 master

interface eth0

virtual_router_id 51 # 0-255 在同一个 instance 中一致 在整个 vrrp 中唯一

priority 150 #优先级，优先级最大的会成为 master

authentication {

auth_type PASS

auth_pass 1111

}

track_script { #检查脚本

chk_nginx

}

virtual_ipaddress { #此实例的浮动 IP

172.16.1.20

}

}

vrrp_instance Nginx2 {

state BACKUP

interface eth0

virtual_router_id 52

priority 110

authentication {

auth_type PASS

auth_pass 1111

}

virtual_ipaddress {

172.16.1.21

}

}

保存退出

—————————————————————–

检测脚本：

#vi/usr/local/keepalived/etc/check_http.sh

————————————————————

#!/bin/bash

if [ "$(ps -ef | grep "nginx: master process"| grep -v grep )" == "" ]

then

killall -9 keepalived

fi

保存退出

———————————————

3、nginx备服务器的keepalived配置

vi /etc/keepalived/keepalived.conf

——————————————————

! Configuration File for keepalived

# written by

ucg.me

global_defs {

router_id Nginx_Id_2

}

vrrp_script chk_nginx {

script “/usr/local/keepalived/etc/check_http.sh”

interval 2

weight 2

}

vrrp_instance Nginx1 {

state BACKUP

interface eth0

virtual_router_id 51

priority 110

authentication {

auth_type PASS

auth_pass 1111

}

virtual_ipaddress {

172.16.1.20

}

}

vrrp_instance Nginx2 {

state MASTER

interface eth0

virtual_router_id 52

priority 150

authentication {

auth_type PASS

auth_pass 1111

}

track_script {

chk_nginx

}

virtual_ipaddress {

172.16.1.21

}

}

六、总结

nginx+keepalived双机互备就此结束。