下文给大家带来基于Linux Centos7下 keepalived + nginx负载均衡的一些问题解答，希望能够给大家在实际运用中带来一定的帮助，负载均衡涉及的东西比较多，理论也不多，网上有很多书籍，今天我们就用创新互联在行业内累计的经验来做一个解答。
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首先需要云服务器关都闭防火墙和selinux
1，准备四台nginx云服务器，两台做代理，两台做后端真实云服务器。
2，配置两台真实云服务器
第一台：
重庆分公司
重庆分公司
[root@vm-4 ~]# systemctl start nginx
[root@vm-4 ~]# systemctl enable nginx
[root@vm-4 conf.d]# echo "server111" > /usr/share/nginx/html/index.html
测试：
[root@vm-4 conf.d]# curl localhost
server111第二台：
[root@vm-5 ~]# systemctl start nginx
[root@vm-5 ~]# systemctl enable nginx
[root@vm-5 conf.d]# echo "server222" > /usr/share/nginx/html/index.html
测试：
[root@vm-5 conf.d]# curl localhost
server2223，配置两台nginx代理云服务器
[root@vm-2 ~]# systemctl start nginx
[root@vm-2 ~]# systemctl enable nginx
[root@vm-2 ~]# cd /etc/nginx/conf.d/
[root@vm-2 conf.d]# cp default.conf proxy.conf
[root@vm-2 conf.d]# mv default.conf default.conf.bak
[root@vm-2 conf.d]# vi upstream.conf
upstream nginx_pool {
server 10.30.161.241:80 weight=1 max_fails=2 fail_timeout=2;
server 10.30.161.242:80 weight=1 max_fails=2 fail_timeout=2;
}
[root@vm-2 conf.d]# vi proxy.conf
location / {
proxy_pass http://nginx_pool;
proxy_redirect default;
proxy_set_header Host $http_host;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header REMOTE-HOST $remote_addr;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
}将nginx的配置文件拷贝到另一台代理云服务器中:
[root@vm-2 conf.d]# scp proxy.conf upstream.conf 10.30.161.214:/etc/nginx/conf.d/
分别重启nginx:
systemctl restart nginx4， 两台代理云服务器分别安装软件
master：
[root@vm-2 conf.d]# yum install -y keepalived
[root@vm-2 conf.d]# cp /etc/keepalived/keepalived.conf /etc/keepalived/keepalived.conf.bak
[root@vm-2 conf.d]# vim /etc/keepalived/keepalived.conf配置keepalived，将里面内容全部删除，添加下列内容：
! Configuration File for keepalived
global_defs {
router_id director1 #辅助改为director2
}
vrrp_instance VI_1 {
state MASTER #定义主还是备
interface ens33 #VIP绑定接口
virtual_router_id 80 #整个集群的调度器一致
priority 100 #back改为50
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
10.30.161.200/24 #设置VIP
}
}
backup:
[root@yum_nginx ~]# cp /etc/keepalived/keepalived.conf
[root@yum_nginx ~]# vi /etc/keepalived/keepalived.conf
配置keepalived，将里面内容全部删除，添加下列内容：
! Configuration File for keepalived
global_defs {
router_id directory2
}
vrrp_instance VI_1 {
state BACKUP
interface ens33
nopreempt
virtual_router_id 80
priority 50
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
10.30.161.200/24
}
}5、两台代理服务器分别启动keepalived
[root@yum_nginx ~]# systemctl enable keepalived.service
[root@yum_nginx ~]# systemctl start keepalived.service6、检测是否成功
在master上 ip a 可显示VIP为10.30.161.200/24
2: ens33: mtu 1500 qdisc pfifo_fast state UP qlen 1000
link/ether 00:0c:29:29:a6:12 brd ff:ff:ff:ff:ff:ff
inet 10.30.161.51/24 brd 10.30.161.255 scope global dynamic ens33
valid_lft 168379sec preferred_lft 168379sec
inet 10.30.161.200/24 scope global secondary ens33
valid_lft forever preferred_lft forever
inet6 fe80::8cfe:8d87:6478:baee/64 scope link
valid_lft forever preferred_lft forever
inet6 fe80::d9c7:8228:5b45:afed/64 scope link tentative dadfailed
valid_lft forever preferred_lft forever 用curl访问VIP，正常轮询
[root@vm-5 conf.d]# curl 10.30.161.200
server111
[root@vm-5 conf.d]# curl 10.30.161.200
server222
[root@vm-5 conf.d]# curl 10.30.161.200
server111
[root@vm-5 conf.d]# curl 10.30.161.200
server222
测试当一台master故障
[root@vm-2 conf.d]# systemctl stop keepalived
ip a 发现VIP偏移到backup代理服务器上
到此：
可以解决心跳故障keepalived
但不能解决Nginx服务故障
扩展对调度器Nginx健康检查（可选）两台都设置
思路：
让Keepalived以一定时间间隔执行一个外部脚本，脚本的功能是当Nginx失败，则关闭本机的Keepalived
(1) script
[root@nginx-proxy-master ~]# vim /etc/keepalived/check_nginx_status.sh#!/bin/bash
#+检查nginx进程是否存在
counter=$(ps -C nginx --no-heading|wc -l) #此行有服务名
if [ "${counter}" = "0" ]; then
#尝试启动一次nginx，停止5秒后再次检测
systemctl start nginx #启动服务
sleep 5
counter=$(ps -C nginx --no-heading|wc -l) #此行有服务名
if [ "${counter}" = "0" ]; then
#如果启动没成功，就杀掉keepalive触发主备切换
service keepalived stop
fi
fi
[root@nginx-proxy-master ~]# chmod a+x /etc/keepalived/check_nginx_status.sh
(2). keepalived使用script
! Configuration File for keepalived
global_defs {
router_id director1
}
vrrp_script check_nginx { #健康检测模块调用
script "/etc/keepalived/check_nginx_status.sh" #指定脚本
interval 5 #检查频率,秒
}
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 {
192.168.246.16/24
}
track_script { 引用脚本
check_nginx
}
}注：必须先启动nginx，再启动keepalived
看了以上关于基于Linux Centos7下 keepalived + nginx负载均衡的一些问题解答，如果大家还有什么地方需要了解的可以在创新互联行业资讯里查找自己感兴趣的或者找我们的专业技术工程师解答的，创新互联技术工程师在行业内拥有十几年的经验了。
