实验环境
代码语言：javascript复制172.16.0.10 keepalived Nginx主负载均衡
172.16.0.8 keepalived Nginx备负载均衡
172.16.0.4 后端服务器WEB节点1(Nginx站点)
172.16.0.5 后端服务器WEB节点2(Nginx站点)在所有服务器上面进行配置
代码语言：javascript复制systemctl stop firewalld #关闭防火墙
setenforce 0 #关闭selinux，临时生效配置后端web服务器(两台配置一样)
代码语言：javascript复制vim /usr/local/nginx/conf/nginx.conf
worker_processes auto;
events {
worker_connections 1024;
}
http {
include mime.types;
default_type application/octet-stream;
server {
listen 80;
server_name www.www.www;
location / {
root /usr/local/nginx/html;
index index.html index.php;
}
}
}启动Nginx
代码语言：javascript复制/usr/local/nginx/sbin/nginx配置负载均衡服务器(两台配置一样)
代码语言：javascript复制vim /usr/local/nginx/conf/nginx.conf
worker_processes auto;
events {
worker_connections 1024;
}
http {
include mime.types;
default_type application/octet-stream;
server {
listen 80;
server_name www.www.www;
location / {
proxy_pass http://backend;
proxy_set_header Host $host:$proxy_port;
proxy_set_header X-Forwarded-For $remote_addr;
}
}
upstream backend {
server 172.16.0.4:80 weight=1 fail_timeout=10s max_fails=1 ;
server 172.16.0.5:80 weight=1 fail_timeout=10s max_fails=1 ;
}
}启动Nginx
代码语言：javascript复制/usr/local/nginx/sbin/nginx测试
搭建keepalived，在两台负载均衡节点上面安装keepalived
安装keeplived(两台负载均衡节点安装)
代码语言：javascript复制yum install keepalived -y在master和backup编辑keeplived文件
代码语言：javascript复制master:
[root@master /]# cp /etc/keepalived/keepalived.conf{,.bak}
[root@master /]# vim /etc/keepalived/keepalived.conf
global_defs {
router_id directory1 #调度器的名称，备调度器改为directory2（两个名字一定不能一样）
}
vrrp_instance VI_1 {
state MASTER #定义主还是备，备用的话写backup
interface ens33 #VIP绑定接口
virtual_router_id 80 #整个集群的调度器一致(在同一个集群)
priority 100 #主调度器优先级 备调度器改为50
advert_int 1 #发包
authentication {
auth_type PASS #主备节点认证信息
auth_pass 1111
}
virtual_ipaddress {
172.16.0.100/24 #VIP 设置为自己网段
}
}backup:
[root@backup /]# cp /etc/keepalived/keepalived.conf{,.bak}
[root@backup /]# vim /etc/keepalived/keepalived.conf
global_defs {
router_id directory2 #调度器的名称，备调度器改为directory2（两个名字一定不能一样）
}
vrrp_instance VI_1 {
state backup #定义主还是备，备用的话写backup
interface ens33 #VIP绑定接口
nopreempt #设置到backup上面，不抢占资源
virtual_router_id 80 #整个集群的调度器一致(在同一个集群)
priority 50
advert_int 1 #发包
authentication {
auth_type PASS #主备节点认证信息
auth_pass 1111
}
virtual_ipaddress {
172.16.0.100/24 #VIP 设置为自己网段
}
}启动keepalived查看VIP IP绑定成功了没
代码语言：javascript复制[root@master /]# systemct start keeplived
[root@backup /]# systemct start keeplivedNginx检测脚本
如果有突发情况使得nginx服务不能启动，但是我们的keepalived服务是正常，这个时候用户是访问不到的，VIP也不会自动漂移到备用的节点服务器上。所以我们需要写一些代码来判断一下Nginx服务是不是正常，如果不正常的话我们就将Nginx服务重新启动，如果Nginx启动不了就将keepalived服务关掉，然后实现VIP的漂移，这个时候用户就不会出现无法访问的情况了。
代码语言：javascript复制vim /etc/keepalived/chk_nginx.sh
#!/bin/sh
# check nginx server status
NGINX=/usr/local/nginx/sbin/nginx
PORT=80
nmap localhost -p $PORT | grep "$PORT/tcp open"
#echo $?
if [ $? -ne 0 ];then
$NGINX -s stop
$NGINX
sleep 2
nmap localhost -p $PORT | grep "$PORT/tcp open"
[ $? -ne 0 ] && systemctl stop keepalived
fi说明：该脚本的意义就是先检测Nginx是否已经开启默认的80端口： 如果存在80端口，一切正常； 如果不存在80端口，就执行if段中的语句：先关一下Nginx，在启动Nginx，等待3秒，再次检测80端口，如果还不存在，则杀死keepalived，
配置keepalived文件
代码语言：javascript复制vim /etc/keepalived/keepalived.conf
global_defs {
router_id directory1
}
vrrp_script chk_nginx {
script "/etc/keepalived/chk_nginx.sh"
interval 3
weight 2
}
vrrp_instance VI_1 {
state MASTER
interface ens33
virtual_router_id 80
priority 100
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
172.16.0.100/24
}
track_script {
chk_nginx
}
}测试
把Nginx文件故意配置错误然后关闭Nginx服务,查看keepalived服务器是否会关闭,然后实现VIP的漂移
