keepalived 学习笔记（二）切换原理（非代码级别分析）
一、切换原理
由于 网络不稳定造成的切换，主要存在以下网络变化场景：
(1) 主机网口上的网线松动掉了；
(2) 主机上重启了网卡服务；
(3) 网络通信慢，或带宽被占满，导致 vrrp 包没有被备机收到；
(4) 主机的 keepalived 服务被重启；
(5) 主机服务器被重启（正常重启）；
(6) 主机服务器被断电重启（非正常重启）；
主备机的 keepalived 在网络不稳定场景下的包交互流程如下图：
(1) 网卡松动场景下（以下所有示例的 advert_int 均设置为了 30s）
此时 主机的 keepalived 日志为：
Jun 21 15:22:21 ha-slave Keepalived_vrrp[1093]: Netlink reports eno1 down Jun 21 15:22:21 ha-slave Keepalived_vrrp[1093]: (product) Entering FAULT STATE Jun 21 15:22:21 ha-slave Keepalived_vrrp[1093]: (product) sent 0 priority Jun 21 15:22:21 ha-slave Keepalived_vrrp[1093]: (product) removing VIPs. Jun 21 15:22:26 ha-slave Keepalived_vrrp[1093]: Netlink reports eno1 up Jun 21 15:22:26 ha-slave Keepalived_vrrp[1093]: (product) Entering BACKUP STATE
备机的 keepalived 日志为：
Jun 21 15:22:51 ha-master Keepalived_vrrp[126758]: (product) Receive advertisement timeout Jun 21 15:22:51 ha-master Keepalived_vrrp[126758]: (product) Entering MASTER STATE Jun 21 15:22:51 ha-master Keepalived_vrrp[126758]: (product) setting VIPs. Jun 21 15:22:51 ha-master Keepalived_vrrp[126758]: Sending gratuitous ARP on eno1 for 10.19.125.172 Jun 21 15:22:51 ha-master Keepalived_vrrp[126758]: (product) Sending/queueing gratuitous ARPs on eno1 for 10.19.125.172 Jun 21 15:22:51 ha-master Keepalived_vrrp[126758]: Sending gratuitous ARP on eno1 for 10.19.125.172 Jun 21 15:22:51 ha-master Keepalived_vrrp[126758]: Sending gratuitous ARP on eno1 for 10.19.125.172 Jun 21 15:22:51 ha-master Keepalived_vrrp[126758]: Sending gratuitous ARP on eno1 for 10.19.125.172 Jun 21 15:22:51 ha-master Keepalived_vrrp[126758]: Sending gratuitous ARP on eno1 for 10.19.125.172 Jun 21 15:22:56 ha-master Keepalived_vrrp[126758]: Sending gratuitous ARP on eno1 for 10.19.125.172 Jun 21 15:22:56 ha-master Keepalived_vrrp[126758]: (product) Sending/queueing gratuitous ARPs on eno1 for 10.19.125.172 Jun 21 15:22:56 ha-master Keepalived_vrrp[126758]: Sending gratuitous ARP on eno1 for 10.19.125.172 Jun 21 15:22:56 ha-master Keepalived_vrrp[126758]: Sending gratuitous ARP on eno1 for 10.19.125.172 Jun 21 15:22:56 ha-master Keepalived_vrrp[126758]: Sending gratuitous ARP on eno1 for 10.19.125.172 Jun 21 15:22:56 ha-master Keepalived_vrrp[126758]: Sending gratuitous ARP on eno1 for 10.19.125.172
可以看到流程如下：
a) 主机上 keepalived 服务检测到服务网卡 down；
b) keepalived vrrp 实例 自主进入 FAULT 状态；
c) keepalived 发送 优先级为 0 的 vrrp包 （但实际网卡上的网线已经松动了，连不上网，所以此时其实这个包发不出去）
d) keepalived 移除 vip；
e) 网线插好之后， keepalived 会自动进入 backup 状态；
f) 备机的 keepalived 在 主机 a) 流程开始其实已经接收不到 vrrp包了，只要接收不到 vrrp 包的时间超过 3倍的 advert_int 就会自主转为 master ，这里是超过 30s ，在 keepalived 日志中可以看到 “Receive advertisement timeout”
以上的转变过程了，为了准确看 f) 流程，可以在主备机上 抓 vrrp 包查看，命令为 ：tcpdump -i 网卡 vrrp -vvv -n
(2) 重启网卡服务的场景下
此时主机上的 keepalived 日志为：
Jun 21 15:24:58 ha-master Keepalived_vrrp[126758]: Netlink reflector reports IP 10.19.125.172 removed from eno1 Jun 21 15:24:58 ha-master Keepalived_vrrp[126758]: (product) Entering BACKUP STATE Jun 21 15:24:58 ha-master Keepalived_vrrp[126758]: (product) sent 0 priority Jun 21 15:24:58 ha-master Keepalived_vrrp[126758]: (product) removing VIPs. Jun 21 15:24:58 ha-master Keepalived_vrrp[126758]: Netlink reports eno1 down Jun 21 15:24:58 ha-master Keepalived_vrrp[126758]: (product) Entering FAULT STATE Jun 21 15:24:58 ha-master Keepalived_vrrp[126758]: Deassigned address fe80::ea61:ff:fe00:ca1 from interface eno1 Jun 21 15:24:58 ha-master Keepalived_vrrp[126758]: Netlink reports eno1 up Jun 21 15:24:58 ha-master Keepalived_vrrp[126758]: (product) Entering BACKUP STATE Jun 21 15:24:58 ha-master Keepalived_vrrp[126758]: product: sending gratuitous ARP for 10.19.125.28 Jun 21 15:24:58 ha-master Keepalived_vrrp[126758]: Sending gratuitous ARP on eno1 for 10.19.125.28 Jun 21 15:25:00 ha-master Keepalived_vrrp[126758]: Assigned address fe80::ea61:ff:fe00:ca1 for interface eno1
备机上的 keepalived 日志为：
Jun 21 15:24:58 ha-slave Keepalived_vrrp[1093]: (product) Backup received priority 0 advertisement Jun 21 15:24:59 ha-slave Keepalived_vrrp[1093]: (product) Receive advertisement timeout Jun 21 15:24:59 ha-slave Keepalived_vrrp[1093]: (product) Entering MASTER STATE Jun 21 15:24:59 ha-slave Keepalived_vrrp[1093]: (product) setting VIPs. Jun 21 15:24:59 ha-slave Keepalived_vrrp[1093]: Sending gratuitous ARP on eno1 for 10.19.125.172 Jun 21 15:24:59 ha-slave Keepalived_vrrp[1093]: (product) Sending/queueing gratuitous ARPs on eno1 for 10.19.125.172 Jun 21 15:24:59 ha-slave Keepalived_vrrp[1093]: Sending gratuitous ARP on eno1 for 10.19.125.172 Jun 21 15:24:59 ha-slave Keepalived_vrrp[1093]: Sending gratuitous ARP on eno1 for 10.19.125.172 Jun 21 15:24:59 ha-slave Keepalived_vrrp[1093]: Sending gratuitous ARP on eno1 for 10.19.125.172 Jun 21 15:24:59 ha-slave Keepalived_vrrp[1093]: Sending gratuitous ARP on eno1 for 10.19.125.172 Jun 21 15:25:04 ha-slave Keepalived_vrrp[1093]: Sending gratuitous ARP on eno1 for 10.19.125.172
可以看到流程如下：
a) 主机 keepalived 首先将 172 这个 VIP 从网卡上移除；
b) 主机 进入 backup 状态，并发送优先级为 0 的 vrrp 包；
c) 备机 keepalived 可以收到这个优先级为 0 的 vrrp 包（此时主机的网卡还没有 down，所以这个包还是可以发送出去的）； 并立刻进入 master 状态；
d) 原先主机 网卡 down状态，keepalived 进入 FAULT 状态，网卡服务启动好之后，网卡 up 状态，keepalived 进入 BACKUP 状态；接收来自 新 主机的 vrrp 包；
在这里有个极端例子，若是网卡重启网卡服务，网卡恢复慢，会造成 重启网卡的 keepalived 从 MASTER --> BACKUP ---> FAULT --> BACKUP ---> MASTER --> BACKUP 的状态不断变化，而原先的备机状态会从 BACKUP ---> MASTER，可以看出原先主机频繁变化，本案例产生这样的效果的配置是： 主备均是物理机非虚拟机，且 advert_int 为 1s，小IP是主机，大IP是备机
主机（28）上的 keepalived 日志为：
Jun 21 15:11:29 ha-master Keepalived_vrrp[126758]: Netlink reflector reports IP 10.19.125.172 removed from eno1
Jun 21 15:11:29 ha-master Keepalived_vrrp[126758]: (product) Entering BACKUP STATE
Jun 21 15:11:29 ha-master Keepalived_vrrp[126758]: (product) sent 0 priority
Jun 21 15:11:29 ha-master Keepalived_vrrp[126758]: (product) removing VIPs.
Jun 21 15:11:29 ha-master Keepalived_vrrp[126758]: Netlink reports eno1 down
Jun 21 15:11:29 ha-master Keepalived_vrrp[126758]: (product) Entering FAULT STATE
Jun 21 15:11:29 ha-master Keepalived_vrrp[126758]: Deassigned address fe80::ea61:ff:fe00:ca1 from interface eno1
Jun 21 15:11:30 ha-master Keepalived_vrrp[126758]: Netlink reports eno1 up
Jun 21 15:11:30 ha-master Keepalived_vrrp[126758]: (product) Entering BACKUP STATE
Jun 21 15:11:30 ha-master Keepalived_vrrp[126758]: product: sending gratuitous ARP for 10.19.125.28
Jun 21 15:11:30 ha-master Keepalived_vrrp[126758]: Sending gratuitous ARP on eno1 for 10.19.125.28
Jun 21 15:11:31 ha-master Keepalived_vrrp[126758]: Assigned address fe80::ea61:ff:fe00:ca1 for interface eno1
Jun 21 15:11:33 ha-master Keepalived_vrrp[126758]: (product) Receive advertisement timeout
Jun 21 15:11:33 ha-master Keepalived_vrrp[126758]: (product) Entering MASTER STATE
Jun 21 15:11:33 ha-master Keepalived_vrrp[126758]: (product) setting VIPs.
Jun 21 15:11:33 ha-master Keepalived_vrrp[126758]: Sending gratuitous ARP on eno1 for 10.19.125.172
Jun 21 15:11:33 ha-master Keepalived_vrrp[126758]: (product) Sending/queueing gratuitous ARPs on eno1 for 10.19.125.172
Jun 21 15:11:33 ha-master Keepalived_vrrp[126758]: Sending gratuitous ARP on eno1 for 10.19.125.172
Jun 21 15:11:33 ha-master Keepalived_vrrp[126758]: Sending gratuitous ARP on eno1 for 10.19.125.172
Jun 21 15:11:33 ha-master Keepalived_vrrp[126758]: Sending gratuitous ARP on eno1 for 10.19.125.172
Jun 21 15:11:33 ha-master Keepalived_vrrp[126758]: Sending gratuitous ARP on eno1 for 10.19.125.172
Jun 21 15:11:34 ha-master Keepalived_vrrp[126758]: (product) Master received advert from 10.19.125.173 with same priority 100 but higher IP address than ours
Jun 21 15:11:34 ha-master Keepalived_vrrp[126758]: (product) Entering BACKUP STATE
Jun 21 15:11:34 ha-master Keepalived_vrrp[126758]: (product) removing VIPs.
备机（173）上的 keepalived 日志为：
Jun 21 15:11:29 ha-slave Keepalived_vrrp[1093]: (product) Backup received priority 0 advertisement Jun 21 15:11:30 ha-slave Keepalived_vrrp[1093]: (product) Receive advertisement timeout Jun 21 15:11:30 ha-slave Keepalived_vrrp[1093]: (product) Entering MASTER STATE Jun 21 15:11:30 ha-slave Keepalived_vrrp[1093]: (product) setting VIPs. Jun 21 15:11:30 ha-slave Keepalived_vrrp[1093]: Sending gratuitous ARP on eno1 for 10.19.125.172 Jun 21 15:11:30 ha-slave Keepalived_vrrp[1093]: (product) Sending/queueing gratuitous ARPs on eno1 for 10.19.125.172 Jun 21 15:11:30 ha-slave Keepalived_vrrp[1093]: Sending gratuitous ARP on eno1 for 10.19.125.172 Jun 21 15:11:30 ha-slave Keepalived_vrrp[1093]: Sending gratuitous ARP on eno1 for 10.19.125.172 Jun 21 15:11:30 ha-slave Keepalived_vrrp[1093]: Sending gratuitous ARP on eno1 for 10.19.125.172 Jun 21 15:11:30 ha-slave Keepalived_vrrp[1093]: Sending gratuitous ARP on eno1 for 10.19.125.172 Jun 21 15:11:34 ha-slave Keepalived_vrrp[1093]: (product) Received advert from 10.19.125.28 with lower priority 100, ours 100, forcing new election Jun 21 15:11:34 ha-slave Keepalived_vrrp[1093]: Sending gratuitous ARP on eno1 for 10.19.125.172 Jun 21 15:11:34 ha-slave Keepalived_vrrp[1093]: (product) Sending/queueing gratuitous ARPs on eno1 for 10.19.125.172 Jun 21 15:11:34 ha-slave Keepalived_vrrp[1093]: Sending gratuitous ARP on eno1 for 10.19.125.172 Jun 21 15:11:34 ha-slave Keepalived_vrrp[1093]: Sending gratuitous ARP on eno1 for 10.19.125.172
通过在备机（173）上 使用命令 tcpdump -i eno1 vrrp -vvv -n 去抓捕整个过程中的 vrrp 包 ，见如下：
15:11:28.412259 IP (tos 0xc0, ttl 255, id 280, offset 0, flags [none], proto VRRP (112), length 40) 10.19.125.28 > 10.19.125.173: vrrp 10.19.125.28 > 10.19.125.173: VRRPv2, Advertisement, vrid 172, prio 100, authtype simple, intvl 1s, length 20, addrs: 10.19.125.172 auth "123456^@^@" 15:11:29.412319 IP (tos 0xc0, ttl 255, id 281, offset 0, flags [none], proto VRRP (112), length 40) 10.19.125.28 > 10.19.125.173: vrrp 10.19.125.28 > 10.19.125.173: VRRPv2, Advertisement, vrid 172, prio 100, authtype simple, intvl 1s, length 20, addrs: 10.19.125.172 auth "123456^@^@" 15:11:29.666703 IP (tos 0xc0, ttl 255, id 282, offset 0, flags [none], proto VRRP (112), length 40) 10.19.125.28 > 10.19.125.173: vrrp 10.19.125.28 > 10.19.125.173: VRRPv2, Advertisement, vrid 172, prio 0, authtype simple, intvl 1s, length 20, addrs: 10.19.125.172 auth "123456^@^@" 15:11:30.276291 IP (tos 0xc0, ttl 255, id 232, offset 0, flags [none], proto VRRP (112), length 40) 10.19.125.173 > 10.19.125.28: vrrp 10.19.125.173 > 10.19.125.28: VRRPv2, Advertisement, vrid 172, prio 100, authtype simple, intvl 1s, length 20, addrs: 10.19.125.172 auth "123456^@^@" 15:11:31.276328 IP (tos 0xc0, ttl 255, id 233, offset 0, flags [none], proto VRRP (112), length 40) 10.19.125.173 > 10.19.125.28: vrrp 10.19.125.173 > 10.19.125.28: VRRPv2, Advertisement, vrid 172, prio 100, authtype simple, intvl 1s, length 20, addrs: 10.19.125.172 auth "123456^@^@" 15:11:32.276370 IP (tos 0xc0, ttl 255, id 234, offset 0, flags [none], proto VRRP (112), length 40) 10.19.125.173 > 10.19.125.28: vrrp 10.19.125.173 > 10.19.125.28: VRRPv2, Advertisement, vrid 172, prio 100, authtype simple, intvl 1s, length 20, addrs: 10.19.125.172 auth "123456^@^@" 15:11:33.276408 IP (tos 0xc0, ttl 255, id 235, offset 0, flags [none], proto VRRP (112), length 40) 10.19.125.173 > 10.19.125.28: vrrp 10.19.125.173 > 10.19.125.28: VRRPv2, Advertisement, vrid 172, prio 100, authtype simple, intvl 1s, length 20, addrs: 10.19.125.172 auth "123456^@^@" 15:11:34.276446 IP (tos 0xc0, ttl 255, id 236, offset 0, flags [none], proto VRRP (112), length 40) 10.19.125.173 > 10.19.125.28: vrrp 10.19.125.173 > 10.19.125.28: VRRPv2, Advertisement, vrid 172, prio 100, authtype simple, intvl 1s, length 20, addrs: 10.19.125.172 auth "123456^@^@" 15:11:34.684150 IP (tos 0xc0, ttl 255, id 283, offset 0, flags [none], proto VRRP (112), length 40) 10.19.125.28 > 10.19.125.173: vrrp 10.19.125.28 > 10.19.125.173: VRRPv2, Advertisement, vrid 172, prio 100, authtype simple, intvl 1s, length 20, addrs: 10.19.125.172 auth "123456^@^@" 15:11:34.684219 IP (tos 0xc0, ttl 255, id 237, offset 0, flags [none], proto VRRP (112), length 40) 10.19.125.173 > 10.19.125.28: vrrp 10.19.125.173 > 10.19.125.28: VRRPv2, Advertisement, vrid 172, prio 100, authtype simple, intvl 1s, length 20, addrs: 10.19.125.172 auth "123456^@^@" 15:11:35.684284 IP (tos 0xc0, ttl 255, id 238, offset 0, flags [none], proto VRRP (112), length 40) 10.19.125.173 > 10.19.125.28: vrrp 10.19.125.173 > 10.19.125.28: VRRPv2, Advertisement, vrid 172, prio 100, authtype simple, intvl 1s, length 20, addrs: 10.19.125.172 auth "123456^@^@" 15:11:36.684319 IP (tos 0xc0, ttl 255, id 239, offset 0, flags [none], proto VRRP (112), length 40) 10.19.125.173 > 10.19.125.28: vrrp 10.19.125.173 > 10.19.125.28: VRRPv2, Advertisement, vrid 172, prio 100, authtype simple, intvl 1s, length 20, addrs: 10.19.125.172 auth "123456^@^@" 15:11:37.684349 IP (tos 0xc0, ttl 255, id 240, offset 0, flags [none], proto VRRP (112), length 40) 10.19.125.173 > 10.19.125.28: vrrp 10.19.125.173 > 10.19.125.28: VRRPv2, Advertisement, vrid 172, prio 100, authtype simple, intvl 1s, length 20, addrs: 10.19.125.172 auth "123456^@^@" 15:11:38.684382 IP (tos 0xc0, ttl 255, id 241, offset 0, flags [none], proto VRRP (112), length 40) 10.19.125.173 > 10.19.125.28: vrrp 10.19.125.173 > 10.19.125.28: VRRPv2, Advertisement, vrid 172, prio 100, authtype simple, intvl 1s, length 20, addrs: 10.19.125.172 auth "123456^@^@"
分析 上面三份资料，可以得到如下流程：
a) 15:11:29.412319 备机收到主机发送的 优先级为 100 的 vrrp 包，此前都是每秒收到一次；
b) Jun 21 15:11:29 28 重启了网卡，进入 backup 状态，同时发送了 优先级为 0的 vrrp 包；
c) 备机 (173) 收到了 这个 vrrp 包，时间为 5:11:29.666703 ,并立即在 15:11:30.276291 向 28 发送了优先级为 100 的 vrrp 包；
d) 备机 （173） 在 c) 发送 vrrp 包的同时，进入 master 状态；后续每隔 1s 都会向 28 发送 优先级为 100 的 vrrp 包；
e) 28 服务器 在网卡服务启动之后，Jun 21 15:11:30 进入BACUKUP 状态，但是可能一直过了 3s ，网卡都没有准备好且收到 来自 173 的 vrrp 包，因此 在 Jun 21 15:11:33 转为了 master 状态；
f）现在可以知道 28 和 173 都是 master 了，因此双方都向对端发送了优先级为 100 的 vrrp 包，28 收到 来自 173 的 vrpp 包之后，判断 优先级相同情况下，对端 IP 大于自己，因此转为 BACKUP 状态；
由上可以看出在网卡启动恢复过程中若时间超过了 3s ，也就是 超过 3倍 的 advert_int 指定的时间，就会自动转为 MASTER 状态，因此 advert_int 还是要设置稍长点，比如 10s.
在脑裂的情况下，及都是 master 的时候，若 vrrp 包优先级相同，则会根据 IP 来决策谁是 MASTER。规则为：IP谁大，谁是 MASTER；
(3) 主机的 keepalived 服务被重启的场景下
主机 为 173 ，备机为 28，advert_int 为 10，173 和 28 都配置成了 初始状态为 BACKUP，优先级为 100 ，非抢占式。
此时主机 keepalived 的日志为：
Jun 21 15:26:35 ha-slave Keepalived[1092]: Stopping Jun 21 15:26:35 ha-slave Keepalived_vrrp[1093]: (product) sent 0 priority Jun 21 15:26:35 ha-slave Keepalived_vrrp[1093]: (product) removing VIPs. Jun 21 15:26:36 ha-slave Keepalived_vrrp[1093]: Stopped - used 0.662641 user time, 4.267257 system time Jun 21 15:26:36 ha-slave Keepalived[1092]: Stopped Keepalived v2.0.20 (01/22,2020) Jun 21 15:26:36 ha-slave Keepalived[78393]: Starting Keepalived v2.0.20 (01/22,2020) Jun 21 15:26:36 ha-slave Keepalived[78393]: Running on Linux 3.10.0-1127.18.2.el7.x86_64 #1 SMP Tue Sep 1 11:13:23 EDT 2020 (built for Linux 3.10.0) Jun 21 15:26:36 ha-slave Keepalived[78393]: Command line: '/usr/local/keepalived/keepalived/sbin/keepalived' '-D' '-d' '-S' '0' Jun 21 15:26:36 ha-slave Keepalived[78393]: Opening file '/etc/keepalived/keepalived.conf'. Jun 21 15:26:36 ha-slave Keepalived[78393]: Opening file './conf/keepalived-product.conf'. Jun 21 15:26:36 ha-slave Keepalived[78394]: Starting VRRP child process, pid=78395 Jun 21 15:26:36 ha-slave Keepalived_vrrp[78395]: Registering Kernel netlink reflector Jun 21 15:26:36 ha-slave Keepalived_vrrp[78395]: Registering Kernel netlink command channel Jun 21 15:26:36 ha-slave Keepalived_vrrp[78395]: Opening file '/etc/keepalived/keepalived.conf'. Jun 21 15:26:36 ha-slave Keepalived_vrrp[78395]: Opening file './conf/keepalived-product.conf'. Jun 21 15:26:36 ha-slave Keepalived_vrrp[78395]: WARNING - default user 'keepalived_script' for script execution does not exist - please create. Jun 21 15:26:36 ha-slave Keepalived_vrrp[78395]: Unsafe permissions found for script '/etc/keepalived/product/bin/health_check.sh'. Jun 21 15:26:36 ha-slave Keepalived_vrrp[78395]: SECURITY VIOLATION - scripts are being executed but script_security not enabled. There are insecure scripts. Jun 21 15:26:36 ha-slave Keepalived_vrrp[78395]: Assigned address 10.19.125.173 for interface eno1 Jun 21 15:26:36 ha-slave Keepalived_vrrp[78395]: Assigned address fe80::ea61:ff:fe00:cad for interface eno1 Jun 21 15:26:36 ha-slave Keepalived_vrrp[78395]: Registering gratuitous ARP shared channel Jun 21 15:26:36 ha-slave Keepalived_vrrp[78395]: (product) removing VIPs. Jun 21 15:26:36 ha-slave Keepalived_vrrp[78395]: ------< Global definitions >------ Jun 21 15:26:36 ha-slave Keepalived_vrrp[78395]: Network namespace = (default) 。。。。。。。。。。。。。。 Jun 21 15:26:36 ha-slave Keepalived_vrrp[78395]: Reset promote_secondaries counter 0 Jun 21 15:26:36 ha-slave Keepalived_vrrp[78395]: Tracking VRRP instances = 0 Jun 21 15:26:36 ha-slave Keepalived_vrrp[78395]: (product) Entering BACKUP STATE (init) Jun 21 15:26:36 ha-slave Keepalived_vrrp[78395]: VRRP sockpool: [ifindex(2), family(IPv4), proto(112), unicast(1), fd(11,12)]
备机的 keepalived 的日志为：
Jun 21 15:26:35 ha-master Keepalived_vrrp[126758]: (product) Backup received priority 0 advertisement Jun 21 15:26:35 ha-master Keepalived_vrrp[126758]: (product) Receive advertisement timeout Jun 21 15:26:35 ha-master Keepalived_vrrp[126758]: (product) Entering MASTER STATE Jun 21 15:26:35 ha-master Keepalived_vrrp[126758]: (product) setting VIPs. Jun 21 15:26:35 ha-master Keepalived_vrrp[126758]: Sending gratuitous ARP on eno1 for 10.19.125.172 Jun 21 15:26:35 ha-master Keepalived_vrrp[126758]: (product) Sending/queueing gratuitous ARPs on eno1 for 10.19.125.172 Jun 21 15:26:35 ha-master Keepalived_vrrp[126758]: Sending gratuitous ARP on eno1 for 10.19.125.172 Jun 21 15:26:35 ha-master Keepalived_vrrp[126758]: Sending gratuitous ARP on eno1 for 10.19.125.172 Jun 21 15:26:35 ha-master Keepalived_vrrp[126758]: Sending gratuitous ARP on eno1 for 10.19.125.172 Jun 21 15:26:35 ha-master Keepalived_vrrp[126758]: Sending gratuitous ARP on eno1 for 10.19.125.172
变化流程如下：
a) 主机 keepalived 停止时，在 Jun 21 15:26:35 发送了优先级为 0 的 vrrp 包，并移除了 VIP
b) 备机在 Jun 21 15:26:35 接收到优先级为0的 vrrp 包，立刻转为了 MASTER 状态
c) 主机 keepalived 启动成功之后直接转为 BACKUP状态
上面主备的状态都比较稳定，没有发生频繁切换的现象。
(4) 主机服务器被重启（reboot）场景下
主机 为 173 ，备机为 28，advert_int 为 10，173 和 28 都配置成了 初始状态为 BACKUP，优先级为 100 ，非抢占式。
此时主机 keepalived 的日志为：
Jun 21 16:54:09 ha-slave Keepalived[945]: Starting Keepalived v2.0.20 (01/22,2020) Jun 21 16:54:09 ha-slave Keepalived[945]: Running on Linux 3.10.0-1127.18.2.el7.x86_64 #1 SMP Tue Sep 1 11:13:23 EDT 2020 (built for Linux 3.10.0) Jun 21 16:54:09 ha-slave Keepalived[945]: Command line: '/usr/local/keepalived/keepalived/sbin/keepalived' '-D' '-d' '-S' '0' Jun 21 16:54:09 ha-slave Keepalived[945]: Opening file '/etc/keepalived/keepalived.conf'. Jun 21 16:54:09 ha-slave Keepalived[945]: Opening file './conf/keepalived-product.conf'. Jun 21 16:54:09 ha-slave Keepalived[1141]: Starting VRRP child process, pid=1142 Jun 21 16:54:09 ha-slave Keepalived_vrrp[1142]: Registering Kernel netlink reflector 。。。。。。。。。。。。。。。。。。。。。。。。 Jun 21 16:54:09 ha-slave Keepalived_vrrp[1142]: Tracking VRRP instances = 0 Jun 21 16:54:09 ha-slave Keepalived_vrrp[1142]: (product) Entering BACKUP STATE (init) Jun 21 16:54:09 ha-slave Keepalived_vrrp[1142]: VRRP sockpool: [ifindex(2), family(IPv4), proto(112), unicast(1), fd(11,12)] Jun 21 16:54:09 ha-slave Keepalived_vrrp[1142]: VRRP_Script(productHealthCheck) succeeded Jun 21 16:54:13 ha-slave Keepalived_vrrp[1142]: Assigned address 10.19.125.173 for interface eno1
备机的 keepalived 的日志为：
Jun 21 16:51:25 ha-master Keepalived_vrrp[126758]: (product) Backup received priority 0 advertisement Jun 21 16:51:26 ha-master Keepalived_vrrp[126758]: (product) Receive advertisement timeout Jun 21 16:51:26 ha-master Keepalived_vrrp[126758]: (product) Entering MASTER STATE Jun 21 16:51:26 ha-master Keepalived_vrrp[126758]: (product) setting VIPs. Jun 21 16:51:26 ha-master Keepalived_vrrp[126758]: Sending gratuitous ARP on eno1 for 10.19.125.172 Jun 21 16:51:26 ha-master Keepalived_vrrp[126758]: (product) Sending/queueing gratuitous ARPs on eno1 for 10.19.125.172 Jun 21 16:51:26 ha-master Keepalived_vrrp[126758]: Sending gratuitous ARP on eno1 for 10.19.125.172 Jun 21 16:51:26 ha-master Keepalived_vrrp[126758]: Sending gratuitous ARP on eno1 for 10.19.125.172 Jun 21 16:51:26 ha-master Keepalived_vrrp[126758]: Sending gratuitous ARP on eno1 for 10.19.125.172 Jun 21 16:51:26 ha-master Keepalived_vrrp[126758]: Sending gratuitous ARP on eno1 for 10.19.125.172 Jun 21 16:51:31 ha-master Keepalived_vrrp[126758]: Sending gratuitous ARP on eno1 for 10.19.125.172 Jun 21 16:51:31 ha-master Keepalived_vrrp[126758]: (product) Sending/queueing gratuitous ARPs on eno1 for 10.19.125.172 Jun 21 16:51:31 ha-master Keepalived_vrrp[126758]: Sending gratuitous ARP on eno1 for 10.19.125.172 Jun 21 16:51:31 ha-master Keepalived_vrrp[126758]: Sending gratuitous ARP on eno1 for 10.19.125.172 Jun 21 16:51:31 ha-master Keepalived_vrrp[126758]: Sending gratuitous ARP on eno1 for 10.19.125.172 Jun 21 16:51:31 ha-master Keepalived_vrrp[126758]: Sending gratuitous ARP on eno1 for 10.19.125.172
变化流程如下：
a) 备机在 Jun 21 16:51:25 就收到来自 主机发送的 优先级为 0 的 vrrp 包，因此直接转为 MASTER状态，并开始对外发送 vrrp包；
b) 主机在 启动之后直接进入 BACKUP 状态，由于在进入该状态之后 30s 可以收到 vrrp 包，因此保持BACKUP状态，未作切换了；
