kern/104377: [carp] [patch] CARP interface doesn't go up on VmWare

[Ari Suutari]

Hi,

> On Tue, Dec 05, 2006 at 08:23:50AM +0200, Ari Suutari wrote:
> A> Hi,
> A> 
> A> OK, what would then be the right fix to get things working 
> A> under vmware ? I run a bunch of servers here and some of
> A> them are redundant pairs. We have some pressure to virtualize
> A> those servers, but we cannot do it as the carp does not work.
> A> 
> A> I don't really get it why the link state is so important here, as
> A> to my understanding carp works in similar as vrrp, using
> A> heartbeats ? Also, the current state of matters is more confusing,
> A> since you can get the carp interface up by issuing another
> A> "ifconfig up" (people suggested this to me, but I cannot accept
> A> that a system providing redundancy requires this kind of kludgery)
> A> 
> A> I can accept that my solution is not the correct one, but
> A> it is a little hard to accept turning it down without
> A> giving any suggestion how to really fix things.
> 
> When one created a redundant routers, he enables CARP an all
> interfaces of the router. Imagine, that one interface goes down,
> but CARP doesn't notice that and keeps claiming to be the master
> on the other interfaces. Traffic comes to it, and it sends it to
> downed interface. 

    Doesn't the other machine notice this from the absense of hearbeat
    on that interface ? I thought that this could combined with
    net.inet.carp.preempt sysctl to force carp to fail over the
    other interfaces in this case also. If this doesn't work then you
    are right; I really didn't test this under vmware (I should
    have tested it, of course).

> 
> If interface, that went down, had reported its state then CARP
> would had noticed that and would had lowered its priority, 
> gave up mastering, and became backup. This will be redundant.

    Is it impossible to add link state reporting to lnc driver ?
    I think this would be the perfect fix and acceptable by
    everyone.

        Ari S.

> 
> A> ----- Original Message ----- 
> A> From: "Gleb Smirnoff" <glebius at FreeBSD.org>
> A> To: <ari.suutari at syncrontech.com>; <glebius at FreeBSD.org>; 
> A> <freebsd-bugs at FreeBSD.org>
> A> Sent: Monday, December 04, 2006 5:38 PM
> A> Subject: Re: kern/104377: [carp] [patch] CARP interface doesn't go up on 
> A> VmWare
> A> 
> A> 
> A> >Synopsis: [carp] [patch] CARP interface doesn't go up on VmWare
> A> >
> A> >State-Changed-From-To: open->closed
> A> >State-Changed-By: glebius
> A> >State-Changed-When: Mon Dec 4 15:34:00 UTC 2006
> A> >State-Changed-Why: 
> A> >I am sorry, but I am not going to commit this patch. Let me explain.
> A> >CARP is not going to work properly on interfaces that do not report
> A> >its state being changed. The proposed patch will change CARP behavior
> A> >to be pretending to work when interface doesn't support reporting
> A> >its link state. I think it is better to refuse to work earlier, then
> A> >pretend to be working but don't provide any redundancy. The proposed
> A> >patch is going to confuse people.
> A> >
> A> >http://www.freebsd.org/cgi/query-pr.cgi?pr=104377
> 
> -- 
> Totus tuus, Glebius.
> GLEBIUS-RIPN GLEB-RIPE
> 
>