keepalived 高可用主备VIP快速部署

IP规划

192.168.4.20 VIP虚拟地址 192.168.4.21 keepalived1 192.168.4.22 keepalived2

网卡为 ens192

系统为Anolis8 龙蜥8

关闭防火墙

systemctl stop firewalld && systemctl disable firewalld

软件安装

主机1
192.168.4.21 keepalived1
安装

yum install -y keepalived

配置文件备份

cp /etc/keepalived/keepalived.conf /etc/keepalived/keepalived.conf.bak

编辑
vi /etc/keepalived/keepalived.conf

! Configuration File for keepalived global_defs { router_id keepalived1 #只是名字而已，辅节点改为keepalived2（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 ens192 #VIP绑定接口 virtual_router_id 66 #整个集群的调度器一致（在同一个集群） priority 100 #（优先权）back改为50（50一间隔） advert_int 1 #发包 authentication { auth_type PASS #主备节点认证 auth_pass 1111 } virtual_ipaddress { 192.168.4.20/24 #VIP（自己网段的） } }

主机2
192.168.4.22 keepalived2
安装软件

yum install -y keepalived

配置文件备份

cp /etc/keepalived/keepalived.conf /etc/keepalived/keepalived.conf.bak

编辑
vi /etc/keepalived/keepalived.conf

! Configuration File for keepalived global_defs { router_id keepalived2 } vrrp_instance VI_1 { state BACKUP #设置为backup interface ens192 nopreempt #设置到back上面，不抢占资源 virtual_router_id 66 priority 50 #辅助改为50 advert_int 1 #检测间隔1s authentication { auth_type PASS auth_pass 1111 #认证类型和密码主备一样，要不然无法互相认证 } virtual_ipaddress { 192.168.4.20/24 #抢占的VIP也一样 } }

启动服务

systemctl enable --now keepalived

重启主机1，VIP自动漂移到主机2，启动主机1，VIP漂回来

配置业务

在两台主机上安装nginx

yum install nginx -y systemctl enable --now nginx

两台主机显示不同网页
主机1

echo "keepalived1 nginx" > /usr/share/nginx/html/index.html

主机2

echo "keepalived2 nginx" > /usr/share/nginx/html/index.html

两台主机访问nginx业务正常

配置nginx高可用检测

两台主机均编写脚本
vi /etc/keepalived/check_nginx.sh
通过端口监听判断业务是否正常，几乎适用于所有业务，如MQ、nginx、OBProxy等等

#!/bin/bash # 检查80端口是否有监听 if ss -tuln | grep -q ':80b'; then exit 0 # 检测成功，返回0 else exit 1 # 检测失败，返回1 fi

配置keepalived1
192.168.4.21 keepalived1
执行权限

chmod +x /etc/keepalived/check_nginx.sh

编辑配置文件
vi /etc/keepalived/keepalived.conf

! Configuration File for keepalived global_defs { router_id keepalived1 #只是名字而已，辅节点改为keepalived2（两个名字一定不能一样） } vrrp_script check_nginx { script "/etc/keepalived/check_nginx.sh" interval 2 #每2秒执行一次 } vrrp_instance VI_1 { state MASTER #定义主还是备，备用的话写backup interface ens192 #VIP绑定接口 virtual_router_id 66 #整个集群的调度器一致（在同一个集群） priority 100 #（优先权）back改为50（50一间隔） advert_int 1 #发包 authentication { auth_type PASS #主备节点认证 auth_pass 1111 } virtual_ipaddress { 192.168.4.20/24 #VIP（自己网段的） } track_script { check_nginx } }

配置keepalived2
192.168.4.22 keepalived2
执行权限

chmod +x /etc/keepalived/check_nginx.sh

编辑配置文件
vi /etc/keepalived/keepalived.conf

! Configuration File for keepalived global_defs { router_id keepalived2 } vrrp_script check_nginx { script "/etc/keepalived/check_nginx.sh" interval 2 #每2秒执行一次 } vrrp_instance VI_1 { state BACKUP #设置为backup interface ens192 nopreempt #设置到back上面，不抢占资源 virtual_router_id 66 priority 50 #辅助改为50 advert_int 1 #检测间隔1s authentication { auth_type PASS auth_pass 1111 #认证类型和密码主备一样，要不然无法互相认证 } virtual_ipaddress { 192.168.4.20/24 #抢占的VIP也一样 } track_script { check_nginx } }

改完配置文件两台主机都需要重启keepalived服务

关闭主机1的nginx服务，VIP自动漂移到主机2，启动主机1的nginx服务，VIP漂回来

配置为单播，抵御脑裂

配置keepalived1
192.168.4.21 keepalived1
编辑配置文件
vi /etc/keepalived/keepalived.conf

! Configuration File for keepalived global_defs { router_id keepalived1 #只是名字而已，辅节点改为keepalived2（两个名字一定不能一样） } vrrp_script check_nginx { script "/etc/keepalived/check_nginx.sh" interval 2 #每2秒执行一次 } vrrp_instance VI_1 { state MASTER #定义主还是备，备用的话写backup interface ens192 #VIP绑定接口 virtual_router_id 66 #整个集群的调度器一致（在同一个集群） priority 100 #（优先权）back改为50（50一间隔） advert_int 1 #发包 authentication { auth_type PASS #主备节点认证 auth_pass 1111 } unicast_src_ip 192.168.4.21 #本机ip unicast_peer { 192.168.4.22 #其他机器ip，可多个 } virtual_ipaddress { 192.168.4.20/24 #VIP（自己网段的） } track_script { check_nginx } }

配置keepalived2
192.168.4.22 keepalived2
编辑配置文件
vi /etc/keepalived/keepalived.conf

! Configuration File for keepalived global_defs { router_id keepalived2 } vrrp_script check_nginx { script "/etc/keepalived/check_nginx.sh" interval 2 #每2秒执行一次 } vrrp_instance VI_1 { state BACKUP #设置为backup interface ens192 nopreempt #设置到back上面，不抢占资源 virtual_router_id 66 priority 50 #辅助改为50 advert_int 1 #检测间隔1s authentication { auth_type PASS auth_pass 1111 #认证类型和密码主备一样，要不然无法互相认证 } unicast_src_ip 192.168.4.22 #本机ip unicast_peer { 192.168.4.21 #其他机器ip，可多个 } virtual_ipaddress { 192.168.4.20/24 #抢占的VIP也一样 } track_script { check_nginx } }

改完配置文件两台主机都需要重启keepalived服务

总结

简单好用！

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