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

Gleb Smirnoff glebius at
Tue Dec 5 02:48:37 PST 2006

On Tue, Dec 05, 2006 at 12:30:27PM +0200, Ari Suutari wrote:
A> >A> OK, what would then be the right fix to get things working 
A> >A> under vmware ? I run a bunch of servers here and some of
A> >A> them are redundant pairs. We have some pressure to virtualize
A> >A> those servers, but we cannot do it as the carp does not work.
A> >A> 
A> >A> I don't really get it why the link state is so important here, as
A> >A> to my understanding carp works in similar as vrrp, using
A> >A> heartbeats ? Also, the current state of matters is more confusing,
A> >A> since you can get the carp interface up by issuing another
A> >A> "ifconfig up" (people suggested this to me, but I cannot accept
A> >A> that a system providing redundancy requires this kind of kludgery)
A> >A> 
A> >A> I can accept that my solution is not the correct one, but
A> >A> it is a little hard to accept turning it down without
A> >A> giving any suggestion how to really fix things.
A> >
A> >When one created a redundant routers, he enables CARP an all
A> >interfaces of the router. Imagine, that one interface goes down,
A> >but CARP doesn't notice that and keeps claiming to be the master
A> >on the other interfaces. Traffic comes to it, and it sends it to
A> >downed interface. 
A>    Doesn't the other machine notice this from the absense of hearbeat
A>    on that interface ? I thought that this could combined with
A>    net.inet.carp.preempt sysctl to force carp to fail over the
A>    other interfaces in this case also. If this doesn't work then you
A>    are right; I really didn't test this under vmware (I should
A>    have tested it, of course).

Yes, it will notice this and claim mastering on the downed net.
However it will fail to get mastering on the other nets.

A> >If interface, that went down, had reported its state then CARP
A> >would had noticed that and would had lowered its priority, 
A> >gave up mastering, and became backup. This will be redundant.
A>    Is it impossible to add link state reporting to lnc driver ?
A>    I think this would be the perfect fix and acceptable by
A>    everyone.

You are 100% right :)

Totus tuus, Glebius.

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