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Problem sorted. It was an ARP issue on the apache servers.
For anyone else who has a similar problem, check your /etc/sysctl.conf on your
apache servers and check you have something like the following (replacting eth0
with your own nic name).
net.ipv4.conf.all.arp_ignore=1
net.ipv4.conf.eth0.arp_ignore=1
net.ipv4.conf.all.arp_announce=2
net.ipv4.conf.eth0.arp_announce=2
Cheers
Mike.
________________________________________
From: Ross Michael (LEEDS PCT) [michael.ross@xxxxxxx]
Sent: 26 July 2011 09:13
To: lvs-users@xxxxxxxxxxxxxxxxxxxxxx
Subject: [lvs-users] Cluster using only one of two available nodes
Hi all,
I have something of a bit of an odd issue that I have so far been unable to
find a solution for, so I am hoping that you can help.
I have a 4 server rig:
2 x directors (heartbeat HA) 192.168.8.111, 192.168.8.112
2 x apache servers 192.168.8.121, 192.168.8.122
Virtual IP 192.168.8.120
The HA directors are set up and appear to be working perfectly (and failing
over correctly). The Apache servers are also working as expected and will both
happily return content when connected to directly by IP. However, when
connecting through the virtual IP, the currently active director will only send
requests to one of the servers and seems to completely ignore the other one.
What makes this rather odd is that the director recognises both apache servers,
checks them regularly for response and reports correctly if either one goes
down.
ipvsadm -Ln
Prot LocalAddress:Port Scheduler Flags
-> RemoteAddress:Port Forward Weight ActiveConn InActConn
TCP 192.168.8.120:80 rr persistent 600
-> 192.168.8.121:80 Route 1 0 0
-> 192.168.8.122:80 Route 1 0 0
You can see both servers. Both are responding to the director alive requests:
Both apache logs report: 192.168.8.111 - - [26/Jul/2011:09:02:30 +0100] "GET
/alive.html HTTP/1.1" 200 12 "-" "libwww-perl/5.805"
The director is set up like this:-
ldirectord.cf:
checktimeout=10
checkinterval=2
autoreload=yes
quiescent=no
virtual=192.168.8.120:80
real=192.168.8.121:80 gate
real=192.168.8.122:80 gate
fallback=127.0.0.1:80 gate
service=http
request="alive.html"
receive="Still alive"
scheduler=rr
protocol=tcp
checktype=negotiate
persistent=600
If I take out 8.121 (the apache server it insists on using), it will not direct
traffic to 8.122. Something else I have noticed is that if no apache server is
available, it will not use the fallback either.
Something else I have noticed, but i am not sure it is relevant is that if I do
a ipvsadm -Ln -stats, I get:
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Conns InPkts OutPkts InBytes OutBytes
-> RemoteAddress:Port
TCP 192.168.8.120:80 358 7618 0 527015 0
-> 192.168.8.121:80 0 0 0 0 0
-> 192.168.8.122:80 0 0 0 0 0
Notice that all the connections are on the virtual IP and the real IP's are
saying zero across the board even though the system appears (on the surface) to
be working properly. I thought that for every connection via the VIP, it would
increment 'Conns, InPkts etc' for the real server, though I could be wrong.
Any thoughts would be most appreciated.
Cheers
Mike
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