[lvs-users] Weird problem after realserver crashes

[Graeme Fowler]

On Fri, 2008-05-09 at 05:13 +0300, Janar Kartau wrote:
> The problem was indeed in the TCP session timeout settings. It defaults 
> to 900 seconds in CentOS 5. Connections made between the realserver 
> crash and pulse removing the node from the LVS config would remain in 
> ESTABLISHED state since director never got a CLOSE. As a result, these 
> dead connections remained in the ipvs table for whole 15 minutes and 
> thus making the realserver useless until the connections finally timed 
> out. I'm surprised nobody had this problem before.

This is what the expire_nodest_conn and expire_quiescent_template
sysctls are for. Toggling them to "on" respectively removes the IPVS
table entries when the realserver is removed from the pool, or removes
any persistence templates when weight = 0.

Graeme