keepalived+lvs子网掩码造成VIP切换故障 架构：keepalived+lvs ，前端调度器是双主模型 现象：keepalived手动停掉一台，但是虚拟IP不会切换 整体网络是24位 VIP：172.18.3.200 keepalived的路由 [root@Sserver3-53 clouder]# route -n Kernel IP routing table Destination Gateway Genmask Flags Metric Ref Use Iface 0.0.0.0 172.18.3.1 0.0.0.0 UG 0 0 0 eth0 169.254.0.0 0.0.0.0 255.255.0.0 U 1002 0 0 eth0 172.18.0.0 0.0.0.0 255.255.0.0 U 0 0 0 eth0 172.18.3.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0 PS：不fail over 原因就是这条16位的路由作怪 : eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000 link/ether 06:cf:56:00:01:3b brd ff:ff:ff:ff:ff:ff inet 172.18.3.53/24 brd 172.18.3.255 scope global eth0 valid_lft forever preferred_lft forever inet 172.18.3.200/16 scope global eth0 #没有secondary valid_lft forever preferred_lft forever inet 172.18.3.201/16 scope global secondary eth0 valid_lft forever preferred_lft forever 解决，配置检查： 后端realserver配置的虚拟IP为： /sbin/ifconfig lo:0 172.18.3.200 broadcast 172.18.3.200 netmask 255.255.255.255 up /sbin/route add -host 172.18.3.200 dev lo:0 前端keepalived： virtual_ipaddress { 172.18.3.200/16 } 明显子网掩码出问题了。 virtual_ipaddress { 172.18.3.200/24 } 重启keepalived，检查现象： [root@Sserver3-53 clouder]# route -n Kernel IP routing table Destination Gateway Genmask Flags Metric Ref Use Iface 0.0.0.0 172.18.3.1 0.0.0.0 UG 0 0 0 eth0 169.254.0.0 0.0.0.0 255.255.0.0 U 1002 0 0 eth0 172.18.3.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0 eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000 link/ether 06:cf:56:00:01:3b brd ff:ff:ff:ff:ff:ff inet 172.18.3.53/24 brd 172.18.3.255 scope global eth0 valid_lft forever preferred_lft forever inet 172.18.3.200/24 scope global secondary eth0 valid_lft forever preferred_lft forever 15.2 keepalived在centos7.2中的bug keepalived 在centos7.2 使用 /bin/systemctl restart keepalived.service 配置文件没有生效 需要使用reload参数来重新生效
参考：
https://www.cnblogs.com/paul8339/p/9644821.html