Traffic to a "dead" server

[Graeme Fowler]

Hello all

On 20/10/2006 13:51, Casey Zacek wrote:
> Ok, I read the HOWTO.  I must have missed the part you're referencing.
> Maybe I'm being misunderstood.

Maybe. Or maybe something else is at play here. These are my 
explanations, not from code:

/proc/sys/net/ipv4/vs/expire_quiescent_template

When set to "1", results in all persistent entries in the output from 
"ipvsadm -L -n -c" disappearing when a realserver becomes quiescent, ie. 
weight is set to 0. With persistence in use, this probably what you want 
if a server fails out of the pool. If you're manually setting weight to 
0 to allow connected clients to terminate gracefully, leave set to 0.

/proc/sys/net/ipv4/vs/expire_nodest_conn

Wen set to "1", results in all established and persistent entries in the 
output from "ipvsadm -L -n -c" disappearing when a realserver becomes 
unreachable (ie. is removed from the pool completely).

So...

In your specific case, you probably want both set to "1" such that 
keepalived will "do the right thing" regardless of the state of the machine:

If the machine is quiesced (weight to 0) then all new connections will 
go elsewhere *and* persistent connections will be cleared. Unfortunately 
this means that session-based applications will have a problem unless 
the session data is shared between all the realservers in some way.

If the machine is removed from the pool completely, all connections will 
be expired. Comments regarding sessions apply here also.

What do you have them set to? And, secondly, have you changed them for 
any reason recently?

Graeme