記一次keepalived腦裂問題查找

在自己環境做keepalived+redis實驗時,當重啓了備用redies機器後,發現兩臺redies主機都拿到了VIP

[root@redis2 ~]# ip addr list
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN 
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
    link/ether 52:54:00:72:6a:7c brd ff:ff:ff:ff:ff:ff
    inet 192.168.122.54/24 brd 192.168.122.255 scope global eth0
    inet 192.168.122.50/32 scope global eth0
    inet6 fe80::5054:ff:fe72:6a7c/64 scope link 
       valid_lft forever preferred_lft forever


[root@localhost ~]# ip addr list
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN 
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
    link/ether 52:54:00:85:7b:a9 brd ff:ff:ff:ff:ff:ff
    inet 192.168.122.96/24 brd 192.168.122.255 scope global eth0
    inet 192.168.122.50/32 scope global eth0
    inet6 fe80::5054:ff:fe85:7ba9/64 scope link 
       valid_lft forever preferred_lft forever


也就是出現了keepalived的腦裂現象,檢查了兩臺主機的網絡連通狀態,發現網絡是好的。然後在備機上抓包

[root@localhost ~]#  tcpdump -i eth0|grep VRRP
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on eth0, link-type EN10MB (Ethernet), capture size 65535 bytes
15:51:17.146322 IP 192.168.122.54 > vrrp.mcast.net: VRRPv2, Advertisement, vrid 51, prio 160, authtype simple, intvl 1s, length 20
15:51:17.146577 IP 192.168.122.96 > vrrp.mcast.net: VRRPv2, Advertisement, vrid 51, prio 50, authtype simple, intvl 1s, length 20
15:51:17.146972 IP 192.168.122.54 > vrrp.mcast.net: VRRPv2, Advertisement, vrid 51, prio 160, authtype simple, intvl 1s, length 20
15:51:18.147136 IP 192.168.122.96 > vrrp.mcast.net: VRRPv2, Advertisement, vrid 51, prio 50, authtype simple, intvl 1s, length 20
15:51:18.147576 IP 192.168.122.54 > vrrp.mcast.net: VRRPv2, Advertisement, vrid 51, prio 160, authtype simple, intvl 1s, length 20
15:51:25.151399 IP 192.168.122.96 > vrrp.mcast.net: VRRPv2, Advertisement, vrid 51, prio 50, authtype simple, intvl 1s, length 20
15:51:25.151942 IP 192.168.122.54 > vrrp.mcast.net: VRRPv2, Advertisement, vrid 51, prio 160, authtype simple, intvl 1s, length 20
15:51:26.151703 IP 192.168.122.96 > vrrp.mcast.net: VRRPv2, Advertisement, vrid 51, prio 50, authtype simple, intvl 1s, length 20
15:51:26.152623 IP 192.168.122.54 > vrrp.mcast.net: VRRPv2, Advertisement, vrid 51, prio 160, authtype simple, intvl 1s, length 20
15:51:27.152456 IP 192.168.122.96 > vrrp.mcast.net: VRRPv2, Advertisement, vrid 51, prio 50, authtype simple, intvl 1s, length 20
15:51:27.153261 IP 192.168.122.54 > vrrp.mcast.net: VRRPv2, Advertisement, vrid 51, prio 160, authtype simple, intvl 1s, length 20
15:51:28.152955 IP 192.168.122.96 > vrrp.mcast.net: VRRPv2, Advertisement, vrid 51, prio 50, authtype simple, intvl 1s, length 20
15:51:28.153461 IP 192.168.122.54 > vrrp.mcast.net: VRRPv2, Advertisement, vrid 51, prio 160, authtype simple, intvl 1s, length 20
15:51:29.153766 IP 192.168.122.96 > vrrp.mcast.net: VRRPv2, Advertisement, vrid 51, prio 50, authtype simple, intvl 1s, length 20
15:51:29.155652 IP 192.168.122.54 > vrrp.mcast.net: VRRPv2, Advertisement, vrid 51, prio 160, authtype simple, intvl 1s, length 20
15:51:30.154275 IP 192.168.122.96 > vrrp.mcast.net: VRRPv2, Advertisement, vrid 51, prio 50, authtype simple, intvl 1s, length 20
15:51:30.154587 IP 192.168.122.54 > vrrp.mcast.net: VRRPv2, Advertisement, vrid 51, prio 160, authtype simple, intvl 1s, length 20
15:51:31.155042 IP 192.168.122.96 > vrrp.mcast.net: VRRPv2, Advertisement, vrid 51, prio 50, authtype simple, intvl 1s, length 20
15:51:31.155428 IP 192.168.122.54 > vrrp.mcast.net: VRRPv2, Advertisement, vrid 51, prio 160, authtype simple, intvl 1s, length 20
15:51:32.155539 IP 192.168.122.96 > vrrp.mcast.net: VRRPv2, Advertisement, vrid 51, prio 50, authtype simple, intvl 1s, length 20
15:51:32.155986 IP 192.168.122.54 > vrrp.mcast.net: VRRPv2, Advertisement, vrid 51, prio 160, authtype simple, intvl 1s, length 20
15:51:33.156357 IP 192.168.122.96 > vrrp.mcast.net: VRRPv2, Advertisement, vrid 51, prio 50, authtype simple, intvl 1s, length 20
15:51:33.156979 IP 192.168.122.54 > vrrp.mcast.net: VRRPv2, Advertisement, vrid 51, prio 160, authtype simple, intvl 1s, length 20
15:51:34.156801 IP 192.168.122.96 > vrrp.mcast.net: VRRPv2, Advertisement, vrid 51, prio 50, authtype simple, intvl 1s, length 20
15:51:34.156989 IP 192.168.122.54 > vrrp.mcast.net: VRRPv2, Advertisement, vrid 51, prio 160, authtype simple, intvl 1s, length 20

備機能接收到master發過來的VRRP廣播,那爲什麼還會有腦裂現象?發現重啓後iptables還開着,檢查了防火牆配置

root@localhost ~]# iptables -S
-P INPUT ACCEPT
-P FORWARD ACCEPT
-P OUTPUT ACCEPT
-A INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT 
-A INPUT -p icmp -j ACCEPT 
-A INPUT -i lo -j ACCEPT 
-A INPUT -p tcp -m state --state NEW -m tcp --dport 22 -j ACCEPT 
-A INPUT -j REJECT --reject-with icmp-host-prohibited 
-A FORWARD -j REJECT --reject-with icmp-host-prohibited 

發現系統不接收VRRP協議,於是修改iptables

[root@localhost ~]# iptables -I INPUT 4 -p vrrp -j ACCEPT
[root@localhost ~]# iptables -S
-P INPUT ACCEPT
-P FORWARD ACCEPT
-P OUTPUT ACCEPT
-A INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT 
-A INPUT -p icmp -j ACCEPT 
-A INPUT -i lo -j ACCEPT 
-A INPUT -p vrrp -j ACCEPT 
-A INPUT -p tcp -m state --state NEW -m tcp --dport 22 -j ACCEPT 
-A INPUT -j REJECT --reject-with icmp-host-prohibited 
-A FORWARD -j REJECT --reject-with icmp-host-prohibited 
[root@localhost ~]# ip addr list
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN 
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
    link/ether 52:54:00:85:7b:a9 brd ff:ff:ff:ff:ff:ff
    inet 192.168.122.96/24 brd 192.168.122.255 scope global eth0
    inet6 fe80::5054:ff:fe85:7ba9/64 scope link 
       valid_lft forever preferred_lft forever
發現VIP沒了。雖然問題解決了,但爲什麼備機明明能抓到master發來的VRRP廣播包,但卻無法改變自身狀態呢?只能說明網卡接收到數據包是在iptables處理數據包之前發生的事情。





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