From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
To: William Lima Reiznautt <willreli@gmail.com>
Cc: qemu-devel@nongnu.org
Subject: Re: Live Migration (L2 network)
Date: Mon, 27 Jul 2020 20:09:09 +0100 [thread overview]
Message-ID: <20200727190909.GA29172@work-vm> (raw)
In-Reply-To: <CAO4s5Y90ZTYLbt1M_JDOJx1wmOY43PEu+cFSw0SHY5BOEqk3pA@mail.gmail.com>
* William Lima Reiznautt (willreli@gmail.com) wrote:
> Hi folks,
>
> I hope everything is well.
Hi,
> Sorry about that doubt in this channel.
No, it's the right place to ask!
> I have a doubt about live migration interacting with layer 2 network, when
> the live migration is running. How does the qemu signal the switch network
> that the qemu instance changes port ? Because when the qemu migration to
> another port switch, the switch has a time to understand that flow is
> changed.
>
> I saw the dump traffic in live migration and I noticed that one packet
> (RARP). "This packet is created by qemu."
>
> Does anyone know if there is documentation on this?
I'm not sure we have documentation, but the code is in net/announce.c in
recent qemu.
When the migration has finished we send an ARP and then, when it starts
running, we tell the guest to send a RARP; we send those a few times
to make sure we don't miss it.
Those are normally enough for the switch to realise that the VM
has moved port; some very complex switch setups are less forgiving - in
recent qemu's you can send the announce again later and/or change the
timing of it.
Dave
> Thanks
>
> - - -
> William Lima Reiznautt
> willreli@gmail.com
> www.ic.unicamp.br/~william
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
prev parent reply other threads:[~2020-07-27 19:10 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-27 11:05 Live Migration (L2 network) William Lima Reiznautt
2020-07-27 19:09 ` Dr. David Alan Gilbert [this message]
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