CentOS 安装 Keepalive 实现节点高可用

假设现在需要在2台 Centos 服务器（192.168.1.101，192.168.1.102）上安装Keepalive，实现高可用（VIP 192.168.1.201）。

1. 安装 keepalived

   yum install -y keepalived
   

2. 修改主节点 keepalived 配置

   cat < /etc/keepalived/keepalived.conf    
   global_defs {
      router_id MASTER01           #实例ID，唯一
   }
   vrrp_instance VI_1 {
       state MASTER                #设置主备状态
       interface enp0s3            #绑定网卡
       virtual_router_id 129       #分组ID(0-255)，主备必须相同
       priority 100                #优先级，主节点值更高
       advert_int 1                #VRRP Multicast广播周期秒数
       authentication {            #认证方式
           auth_type PASS
           auth_pass 123456
       }
       virtual_ipaddress {         #VIP设置
           192.168.1.244
       }
   }
   EOF
   

3. 修改备节点 keepalived 配置

   cat < /etc/keepalived/keepalived.conf    
   global_defs {
      router_id MASTER02           #实例ID，唯一
   }
   vrrp_instance VI_1 {
       state BACKUP                #设置主备状态
       interface enp0s3            #绑定网卡
       virtual_router_id 129       #分组ID(0-255)，主备必须相同
       priority 98                 #优先级，备节点值更低
       advert_int 1                #VRRP Multicast广播周期秒数
       authentication {            #认证方式
           auth_type PASS
           auth_pass 123456
       }
       virtual_ipaddress {         #VIP设置
           192.168.1.244
       }
   }
   EOF
   

4. 注册 keepalived 服务

   systemctl enable keepalived
   systemctl restart keepalived
   

5. 使用ping VIP方式测试，期间可以重启主节点，可以看到ping不会报错，在不到1毫秒内完成切换

   ping 192.168.1.244
   PING 192.168.1.244 (192.168.1.244) 56(84) bytes of data.
   64 bytes from 192.168.1.244: icmp_seq=13 ttl=64 time=0.061 ms
   64 bytes from 192.168.1.244: icmp_seq=14 ttl=64 time=0.063 ms
   64 bytes from 192.168.1.244: icmp_seq=15 ttl=64 time=0.061 ms
   64 bytes from 192.168.1.244: icmp_seq=16 ttl=64 time=0.070 ms
   64 bytes from 192.168.1.244: icmp_seq=17 ttl=64 time=0.130 ms
   64 bytes from 192.168.1.244: icmp_seq=18 ttl=64 time=0.115 ms
   64 bytes from 192.168.1.244: icmp_seq=19 ttl=64 time=0.065 ms
   64 bytes from 192.168.1.244: icmp_seq=20 ttl=64 time=0.110 ms
   64 bytes from 192.168.1.244: icmp_seq=21 ttl=64 time=0.057 ms
   64 bytes from 192.168.1.244: icmp_seq=22 ttl=64 time=0.089 ms