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[lvs-users] Keepalived, localnode and localnode on BACKUP

To: lvs-users@xxxxxxxxxxxxxxxxxxxxxx
Subject: [lvs-users] Keepalived, localnode and localnode on BACKUP
From: Thomas Pedoussaut <thomas@xxxxxxxxxxxxxx>
Date: Tue, 15 Apr 2008 13:31:11 +0100
Hi,

I have a very light infrastructure, with 2 servers acting as directors 
AND real servers.

I came across the packet storm problem where when the MASTER forwards a 
connection to the real server on the BACKUP (via DR), the BACKUP treats 
it as a VIP connection to be loadbalanced rather than a real server 
connection to process. And decides to load balance it back to the MASTER 
.....

I'm sure there is a way to do it, maybe with iptables. I'm looking for a 
schema explaining how a packet coming on an interface traverses the 
various layers (ipvs, netfilter, routing) so I could figure out how to 
do it.
My chance is that I have 2 physical interfaces, one public and one 
private, so if a packet arrives on the private interface for the VIP, 
it's a DR from the MASTER, and if it comes on the public, it's 
pre-loadbalance traffic.

Another option would be to be sure that the tables are in sync between 
the 2 machines so the BACKUP know that the connection has to be directed 
locally. I have tried to setup that feature, but it doesn't seems to 
sync really.


PS: no arp issues (kernel 2.6 with net.ipv4.conf.all.arp_ignore = 1 and 
net.ipv4.conf.all.arp_announce = 2)
PS2: the realserver on the MASTER works fine.
-- 
Thomas




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