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Re: Traffic to a "dead" server

To: "LinuxVirtualServer.org users mailing list." <lvs-users@xxxxxxxxxxxxxxxxxxxxxx>
Subject: Re: Traffic to a "dead" server
From: Casey Zacek <cz@xxxxxxxxxxxx>
Date: Thu, 19 Oct 2006 09:35:28 -0500
As stated, I'm using keepalived, not ldirectord.  But, if I remember
correctly, the quiescent setting causes ldirectord to set the weight
of a RS to 0 when it fails (as opposed to deleting it from the active
list).  keepalived is not doing that; it is definitely deleting the
server from the list.  I verified it with 'ipvsadm -lnf 11'.

Matthew Story wrote (at Thu, Oct 19, 2006 at 09:24:46AM -0500):
> had a similar problem yesterday . . . was fixed.  Are you using a
> "sticky" configuration?  e.g. are you using connection persistence?
> If you are you'll need to set the quiescent=yes to quiescent=no in the
> ldirectord.cf.  This should do the trick.
> 
> On 10/19/06, Casey Zacek <cz@xxxxxxxxxxxx> wrote:
> >
> >I have verified a couple of times that, with one customer in
> >particular, IPVS has sent incoming requests to a RS that had been
> >deleted from the active set of RSes by keepalived.  I verified first
> >that 'ipvsadm -lnf 11' (this customer's site is fwmark 11) showed only
> >the still-alive RS, but then I made a request, and it went to the
> >deleted RS.  This was verified using tcpdump on the RS.
> >
> >At the time, of course, the customer was panicking, so the first
> >action taken was to failover to the other LVS machine.  When we did
> >that, everything started working as desired.  Unfortunately, that
> >leaves us with little opportunity to further troubleshoot the problem.
> >
> >So, my question is this.  Are there any known reasons for this type of
> >behavior to occur?  I realized just today that the kernel is compiled
> >without module support for security reasons, but that netfilter
> >connection tracking is compiled in.  I seem to recall reading long ago
> >that connection tracking and IPVS don't mix very well.  Could this
> >lead to my problem?  What else could cause it?  What steps can I take
> >to gather more information?
> >
> >--
> >Casey Zacek
> >Senior Engineer
> >NeoSpire, Inc.
> >_______________________________________________
> >LinuxVirtualServer.org mailing list - lvs-users@xxxxxxxxxxxxxxxxxxxxxx
> >Send requests to lvs-users-request@xxxxxxxxxxxxxxxxxxxxxx
> >or go to http://www.in-addr.de/mailman/listinfo/lvs-users
> >
> 
> 
> -- 
> regards,
> matt
> _______________________________________________
> LinuxVirtualServer.org mailing list - lvs-users@xxxxxxxxxxxxxxxxxxxxxx
> Send requests to lvs-users-request@xxxxxxxxxxxxxxxxxxxxxx
> or go to http://www.in-addr.de/mailman/listinfo/lvs-users
> 

-- 
Casey Zacek
Senior Engineer
NeoSpire, Inc.

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