###将状态转换记录到nginx的文件，便于通过web查看ha状态（一定注意不要开放到公网）
echo `date` `hostname` $1 $2 $3 $4 $5 $6 > /usr/share/nginx/html/index.html
nginx的部分配置文件，仅供参考
# more /etc/nginx/nginx.conf
###运维管理用途: 用于区别vip跑在那台服务器上
server {
listen 80;
server_name localhost;
location / {
root /usr/share/nginx/html;
index index.html index.htm;
}
## nginx monitor use only
###add by lai monitor nginx status
location /server-status {
stub_status on;
allow 127.0.0.1;
allow 192.168.0.0/24;
}
}
通过启停keepalived和nginx来模拟故障，测试vrrp 实例的状态切换过程（即VIP的漂移）：
/etc/init.d/keepalived start/stop
/etc/init.d/nginx stop start/stop
通过启停em1内网网卡、em2公网网卡来模拟故障，测试vrrp 实例的状态切换过程（即VIP的漂移）
ifdown em1
ifdown em2
查看VIP跑在那台服务器上：
# ip addr show|grep 192.168
inet 192.168.0.101/24 brd 192.168.0.255 scope global em1
inet 192.168.0.105/32 scope global em1
测试：
[root@test28 ~]$ curl 192.168.0.101
Mon Dec 14 16:27:10 CST 2015 proxy101 INSTANCE YN_API_GATEWAY MASTER 202
[root@test28 ~]$ curl 192.168.0.102
Mon Dec 14 16:34:40 CST 2015 proxy102 INSTANCE YN_API_GATEWAY BACKUP 199
[root@test28 ~]$ curl 192.168.0.105
Mon Dec 14 16:27:10 CST 2015 proxy101 INSTANCE YN_API_GATEWAY MASTER 202
# tail /var/log/keepalived.notify.log
Mon Dec 14 16:25:13 CST 2015 [proxy101] keepalived HA role state transition:
Mon Dec 14 16:25:13 CST 2015 [proxy101] keepalived HA role state transition: INSTANCE YN_API_GATEWAY MASTER 202
---------------
---------------
Mon Dec 14 16:26:34 CST 2015 [proxy101] keepalived HA role state transition:
Mon Dec 14 16:26:34 CST 2015 [proxy101] keepalived HA role state transition: INSTANCE YN_API_GATEWAY BACKUP 200
---------------
---------------
Mon Dec 14 16:27:10 CST 2015 [proxy101] keepalived HA role state transition:
Mon Dec 14 16:27:10 CST 2015 [proxy101] keepalived HA role state transition: INSTANCE YN_API_GATEWAY MASTER 202
# tail /var/log/messages
Dec 14 16:27:08 localhost Keepalived_vrrp[74308]: VRRP_Instance(YN_API_GATEWAY) forcing a new MASTER election
Dec 14 16:27:08 localhost Keepalived_vrrp[74308]: VRRP_Instance(YN_API_GATEWAY) forcing a new MASTER election
Dec 14 16:27:09 localhost Keepalived_vrrp[74308]: VRRP_Instance(YN_API_GATEWAY) Transition to MASTER STATE
Dec 14 16:27:10 localhost Keepalived_vrrp[74308]: VRRP_Instance(YN_API_GATEWAY) Entering MASTER STATE
Dec 14 16:27:10 localhost Keepalived_vrrp[74308]: VRRP_Instance(YN_API_GATEWAY) setting protocol VIPs.
Dec 14 16:27:10 localhost Keepalived_vrrp[74308]: VRRP_Instance(YN_API_GATEWAY) Sending gratuitous ARPs on em1 for 192.168.0.105
Dec 14 16:27:10 localhost Keepalived_healthcheckers[74307]: Netlink reflector reports IP 192.168.0.105 added
Dec 14 16:27:10 localhost Keepalived_vrrp[74308]: Remote SMTP server [127.0.0.1]:25 connected.
Dec 14 16:27:10 localhost Keepalived_vrrp[74308]: SMTP alert successfully sent.
Dec 14 16:27:15 localhost Keepalived_vrrp[74308]: VRRP_Instance(YN_API_GATEWAY) Sending gratuitous ARPs on em1 for 192.168.0.105
主备状态转换通知邮件：
通过抓包查看来了解详细的工作过程：
# tcpdump -ni em1 vrrp
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on em1, link-type EN10MB (Ethernet), capture size 65535 bytes
17:36:47.098225 IP 192.168.0.101 > 192.168.0.102: VRRPv2, Advertisement, vrid 101, prio 202, authtype simple, intvl 1s, length 20
17:36:47.388540 IP 192.168.0.22 > 224.0.0.18: VRRPv2, Advertisement, vrid 51, prio 120, authtype simple, intvl 1s, length 20
17:36:48.099409 IP 192.168.0.101 > 192.168.0.102: VRRPv2, Advertisement, vrid 101, prio 202, authtype simple, intvl 1s, length 20
17:36:48.389504 IP 192.168.0.22 > 224.0.0.18: VRRPv2, Advertisement, vrid 51, prio 120, authtype simple, intvl 1s, length 20
17:36:49.100544 IP 192.168.0.101 > 192.168.0.102: VRRPv2, Advertisement, vrid 101, prio 202, authtype simple, intvl 1s, length 20
17:36:49.390487 IP 192.168.0.22 > 224.0.0.18: VRRPv2, Advertisement, vrid 51, prio 120, authtype simple, intvl 1s, length 20
17:36:50.101713 IP 192.168.0.101 > 192.168.0.102: VRRPv2, Advertisement, vrid 101, prio 202, authtype simple, intvl 1s, length 20
17:36:50.391453 IP 192.168.0.22 > 224.0.0.18: VRRPv2, Advertisement, vrid 51, prio 120, authtype simple, intvl 1s, length 20