From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:57770) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZKNjX-0008Fu-2T for qemu-devel@nongnu.org; Wed, 29 Jul 2015 05:33:08 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ZKNjT-0005UW-N2 for qemu-devel@nongnu.org; Wed, 29 Jul 2015 05:33:07 -0400 Received: from mx1.redhat.com ([209.132.183.28]:50312) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZKNjT-0005US-GF for qemu-devel@nongnu.org; Wed, 29 Jul 2015 05:33:03 -0400 Received: from int-mx09.intmail.prod.int.phx2.redhat.com (int-mx09.intmail.prod.int.phx2.redhat.com [10.5.11.22]) by mx1.redhat.com (Postfix) with ESMTPS id 2C4B69022B for ; Wed, 29 Jul 2015 09:33:03 +0000 (UTC) Received: from work-vm (ovpn-116-77.ams2.redhat.com [10.36.116.77]) by int-mx09.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id t6T9X0o9021694 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO) for ; Wed, 29 Jul 2015 05:33:02 -0400 Date: Wed, 29 Jul 2015 10:32:59 +0100 From: "Dr. David Alan Gilbert" Message-ID: <20150729093259.GD2267@work-vm> References: <20150728132213.GA1603@vader> <20150728151946.GF2247@work-vm> <20150729080303.GA7667@vader> <20150729081121.GA2267@work-vm> <20150729084104.GB7667@vader> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20150729084104.GB7667@vader> Subject: Re: [Qemu-devel] Live migration hangs after migration to remote host List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Qemu-devel * Eduardo Otubo (eduardo.otubo@profitbricks.com) wrote: > On Wed, Jul 29, 2015 at 09=11=21AM +0100, Dr. David Alan Gilbert wrote: > > * Eduardo Otubo (eduardo.otubo@profitbricks.com) wrote: > > > On Tue, Jul 28, 2015 at 04=19=46PM +0100, Dr. David Alan Gilbert wrote: > > > > * Eduardo Otubo (eduardo.otubo@profitbricks.com) wrote: > > > > > Hello all, > > > > > > > > > > I'm facing a weird behavior on my tests: I am able to live migrate > > > > > between two virtual machines on my localhost, but not to another > > > > > machine, both using tcp. > > > > > > > > > > * I am using the same arguments on the command line; > > > > > * Both virtual machines uses the same qcow2 file visible through NFS; > > > > > * Both machines are in the same subnet; > > > > > * Migration is being done from intel to intel; > > > > > * Same version of Qemu (github master - f8787f8723); > > > > > > > > > > Using all above I am able to live migrate on the same host: between two > > > > > vms on local host or between two vms in the remote host; but when > > > > > migrating from local to remote, the guest hangs. I still can access its > > > > > console via ctrl+alt+2, though, and everything seems to be normal. If I > > > > > issue a reboote via console on the remote, the guest gets back to > > > > > normal. > > > > > > > > > > Am I missing something here? > > > > > > > > Just checking, but are you saying that as far as qemu is concerned, the migration > > > > is happy, it's just the guest that's hung? > > > > > > That's exactly the case. The console (via ctrl+alt+2) is active and > > > responding to all commands normally, but the screen (ctrl+alt+1) is > > > frozen and I can't interact with it at all. > > > > Are you driving this via libvirt or using qemu monitor directly? > > If the latter, can you please get an 'info migrate' from the source > > and an 'info status' from the destination at the end of migrate. > > I'm using qemu command line directly. And I got the problem :) See > below. > > > > > > > Are the host clocks on the two hosts very close (there are lots of > > > > weird corner cases with mismatched clocks) - same time zone? > > > > > > Yep. Both machines are in the same room and have the clock sync'ed. > > > > OK, good. > > > > > > > > > > Are you using cache=none (given that it's NFS shared) > > > > > > I wasn't. But I tried again with cache=none and I got exactly the same > > > thing. > > > > OK, and this pair of machines, have you tried both directions - i.e. > > going a->b and b->a - do both directions fail? > > Is the NFS server one of the two machines? If it is, and you're using libvirt, > > make sure that the directory the disks are on is an NFS mount on both > > machines; e.g. don't migrate directly from the NFS export. > > > > > Also, I tried with stable-2.2 branch and got the same behavior. I really > > > think that's very unlikely to have unstable code of such an important > > > feature upstream, or on a stable- branch. Most probable thing is that > > > I have something wrong on my environment. > > > > Yes, the challenge is to find what; and if it's something common > > we should try and find a way of spotting it. > > > > > Anyway, I'll keep tetsing different stable- branches until I find > > > something that works for me. I'll keep the mailing list posted. > > > > Could you share the qemu command line so we can see if we can > > spot anything? > > Got the problem! I tried to simplify my qemu command line to the > smallest possible, excluding things I thought it could cause the issue. > With no further due, this is the argument: > > -cpu 'Opteron_G4' > > Without this argument everything works as it should, console responsive > and guest active :) Can you show cat /proc/cpuinfo off the two hosts? (Only one CPU, but please include the whole entry) Dave > It says on the documentation[1] that it's possible to migrate between > AMD and Intel, but I think I got a corner case. Apparently I can't > specify the exact CPU model. Is this a known issue? Couldn't find any > reference on bugzilla or launchpad. > > [1] - http://www.linux-kvm.org/page/Migration > > -- > Eduardo Otubo > ProfitBricks GmbH -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK