Re: [lvs-users] Stopping an real server for upgrade

To: lvs-users@xxxxxxxxxxxxxxxxxxxxxx
Subject: Re: [lvs-users] Stopping an real server for upgrade
From: Arie Skliarouk <skliarie@xxxxxxxxx>
Date: Mon, 20 Sep 2010 11:02:07 +0200
> Is there a way to make loadbalancer to "rehash" it's persistency IP tables
>> so that new requests from IP numbers assigned to the real server with zero
>> weight will be forwarded elsewhere?

Yes, you need to set /proc/sys/net/ipv4/vs/expire_quiescent_template to a
> non-zero value.

Thank for the hint, I have found where the setting is explained in detail.

I understand that with this sysctl no new connections will get forwarded to
the real server. Even ones that previously were assigned to the server via
persistence mechanism.

One thing is still not clear to me: if I set this sysctl to 1 and set weight
of a real server to 0, will the already established connections to the
server get broken?


On Mon, Sep 20, 2010 at 02:16, Simon Horman <horms@xxxxxxxxxxxx> wrote:

> On Sun, Sep 19, 2010 at 06:38:08PM +0200, Arie Skliarouk wrote:
> > Hi,
> >
> > We have a farm of several apache servers. Sometimes the application needs
> to
> > be upgraded. The server must not receive any requests during the upgrade.
> > For that I simply exclude the server from the loadbalancer.
> >
> > I noticed that excluding the server from the loadbalancer "hangs" all
> > pending http requests to the server, thus breaking them. I tried to
> assign
> > zero weight to the real server to be upgraded, but the operation only
> > prevents new IP numbers (we use wlc scheduler) to be assigned to the
> server,
> > requests from IP numbers that already were assigned to the real server
> > continue to arrive to the server.
> >
> Hi Arie,
> Yes, you need to set /proc/sys/net/ipv4/vs/expire_quiescent_template
> to a non-zero value. It is safe to do this any time before you
> want it to take effect. In particular, it is safe to set it when
> you boot the system or initialise LVS.
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