LVS + KeepAlived实现高可用负载均衡

上文已经介绍了lvs和keepalived的基本概念和用法，下面直接做lvs和keepalived来实现高可用负载均衡

配置：

主机名	ip	系统	用途
client	172.16.147.1	mac	客户端
lvs-keepalived-master	172.16.147.154	centos7.5	分发器
lvs-keepalived-slave	172.16.147.155	centos7.5	分发器备
test-nginx1	172.16.147.153	centos7.5	web1
test-nginx2	172.16.147.156	centos7.5	web2
vip

1. 主备调度器安装软件

   [root@lvs-keepalived-master ~]# yum -y install ipvsadm keepalived
   [root@lvs-keepalived-slave ~]# yum -y install ipvsadm keepalived
   2. Keepalived
   lvs-master
   [root@lvs-keepalived-master ~]# vim /etc/keepalived/keepalived.conf
   ! Configuration File for keepalived

   global_defs {
   router_id lvs-keepalived-master #辅助改为lvs-backup
   }

   vrrp_instance VI_1 {
   state MASTER
   interface ens33 #VIP绑定接口
   virtual_router_id 80 #VRID 同一组集群，主备一致
   priority 100 #本节点优先级，辅助改为50
   advert_int 1 #检查间隔，默认为1s
   authentication {
   auth_type PASS
   auth_pass 1111
   }
   virtual_ipaddress {
   172.16.147.101/24 # 可以写多个vip
   }
   }

   virtual_server 172.16.147.101 80 { #LVS配置
   delay_loop 3
   lb_algo rr #LVS调度算法
   lb_kind DR #LVS集群模式（路由模式）
   net_mask 255.255.255.0
   protocol TCP #健康检查使用的协议
   real_server 172.16.147.153 80 {
   weight 1
   inhibit_on_failure #当该节点失败时，把权重设置为0，而不是从IPVS中删除
   TCP_CHECK { #健康检查
   connect_port 80 #检查的端口
   connect_timeout 3 #连接超时的时间
   }
   }
   real_server 172.16.147.156 80 {
   weight 1
   inhibit_on_failure
   TCP_CHECK {
   connect_timeout 3
   connect_port 80
   }
   }
   }

2. 备用机安装和配置

   [root@lvs-keepalived-slave ~]# vim /etc/keepalived/keepalived.conf
   ! Configuration File for keepalived

   global_defs {
   router_id lvs-keepalived-slave
   }

   vrrp_instance VI_1 {
   state BACKUP
   interface ens33
   nopreempt #不抢占资源
   virtual_router_id 80
   priority 50
   advert_int 1
   authentication {
   auth_type PASS
   auth_pass 1111
   }
   virtual_ipaddress {
   172.16.147.101/24
   }
   }
   virtual_server 172.16.147.101 80 {
   delay_loop 3
   lb_algo rr
   lb_kind DR
   net_mask 255.255.255.0
   protocol TCP
   real_server 172.16.147.153 80 {
   weight 1
   inhibit_on_failure
   TCP_CHECK {
   connect_port 80
   connect_timeout 3
   }
   }
   real_server 172.16.147.156 80 {
   weight 1
   inhibit_on_failure
   TCP_CHECK {
   connect_timeout 3
   connect_port 80
   }
   }
   }

3. 启动KeepAlived

   [root@lvs-keepalived-master ~]# systemctl start keepalived
   [root@lvs-keepalived-master ~]# systemctl enable keepalived

   [root@lvs-keepalived-master ~]# ipvsadm -Ln
   IP Virtual Server version 1.2.1 (size=4096)
   Prot LocalAddress:Port Scheduler Flags
   -> RemoteAddress:Port Forward Weight ActiveConn InActConn
   TCP 172.16.147.101:80 rr persistent 20
   -> 172.16.147.153:80 Route 1 0 0
   -> 172.16.147.156:80 Route 0 0 0

4. 所有RS配置(nginx1,nginx2)

   [root@test-nginx1 ~]# yum install -y nginx
   [root@test-nginx2 ~]# yum install -y nginx
   [root@test-nginx1 ~]# echo "ip addr add dev lo 172.16.147.101/32" >> /etc/rc.local
   [root@test-nginx1 ~]# echo "net.ipv4.conf.all.arp_ignore = 1" >> /etc/sysctl.conf
   [root@test-nginx1 ~]# echo "net.ipv4.conf.all.arp_announce = 2" >> /etc/sysctl.conf
   [root@test-nginx1 ~]# sysctl -p
   [root@test-nginx1 ~]# echo "web1..." >> /usr/share/nginx/html/index.html
   [root@test-nginx1 ~]# systemctl start nginx
   [root@test-nginx1 ~]# chmod +x /etc/rc.local

上述步骤实现了两台机器的高可用并进行172.16.147.156和172.16.147.153的负载均衡