[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-devel] Live migration from Qemu 2.12 hosts to Qemu 3.2 hosts,
From: |
Daniel P . Berrangé |
Subject: |
Re: [Qemu-devel] Live migration from Qemu 2.12 hosts to Qemu 3.2 hosts, with VMX flag enabled in the guest? |
Date: |
Fri, 18 Jan 2019 10:21:02 +0000 |
User-agent: |
Mutt/1.10.1 (2018-07-13) |
On Fri, Jan 18, 2019 at 10:16:34AM +0000, Dr. David Alan Gilbert wrote:
> * Paolo Bonzini (address@hidden) wrote:
> > On 18/01/19 11:02, Dr. David Alan Gilbert wrote:
> > >>
> > >> It fails if the flag is set, rather than if any nested virtualization has
> > >> been used before.
> > >>
> > >> I'm concerned I will end up with a requirement for *all* guests to be
> > >> restarted in order to migrate them to the new hosts, rather than just the
> > >> ones that would have a problem.
> > > I think you should be able to migrate from 2.12->3.1 like this, but
> > > you'd hit the problem when you then try and migrate again between your
> > > new QEMUs.
> > >
> > > I guess we could modify it to wire it to machine type, so that
> > > older machine types didn't block.
> >
> > That would also be wrong. The old machine types _could_ be using KVM
> > and they have no way to block the live migration.
> >
> > The solution is to restart the VM using "-cpu host,-vmx".
>
> The problem as Christian explained in that thread is that it was common
> for them to start VMs with vmx enabled but for people not to use it
> on most of the VMs, so we break migration for most VMs even though most
> don't use it.
>
> It might not be robust, but it worked for a lot of people most of the
> time.
Yes, this is exactly why I said we should make the migration blocker
be conditional on any L2 guest having been started. I vaguely recall
someone saying there wasn't any way to detect this situation from
QEMU though ?
Regards,
Daniel
--
|: https://berrange.com -o- https://www.flickr.com/photos/dberrange :|
|: https://libvirt.org -o- https://fstop138.berrange.com :|
|: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|
- [Qemu-devel] Live migration from Qemu 2.12 hosts to Qemu 3.2 hosts, with VMX flag enabled in the guest?, Mark Mielke, 2019/01/18
- Re: [Qemu-devel] Live migration from Qemu 2.12 hosts to Qemu 3.2 hosts, with VMX flag enabled in the guest?, Christian Ehrhardt, 2019/01/18
- Re: [Qemu-devel] Live migration from Qemu 2.12 hosts to Qemu 3.2 hosts, with VMX flag enabled in the guest?, Dr. David Alan Gilbert, 2019/01/18
- Re: [Qemu-devel] Live migration from Qemu 2.12 hosts to Qemu 3.2 hosts, with VMX flag enabled in the guest?, Paolo Bonzini, 2019/01/18
- Re: [Qemu-devel] Live migration from Qemu 2.12 hosts to Qemu 3.2 hosts, with VMX flag enabled in the guest?, Dr. David Alan Gilbert, 2019/01/18
- Re: [Qemu-devel] Live migration from Qemu 2.12 hosts to Qemu 3.2 hosts, with VMX flag enabled in the guest?,
Daniel P . Berrangé <=
- Re: [Qemu-devel] Live migration from Qemu 2.12 hosts to Qemu 3.2 hosts, with VMX flag enabled in the guest?, Paolo Bonzini, 2019/01/18
- Re: [Qemu-devel] Live migration from Qemu 2.12 hosts to Qemu 3.2 hosts, with VMX flag enabled in the guest?, Mark Mielke, 2019/01/18
- Re: [Qemu-devel] Live migration from Qemu 2.12 hosts to Qemu 3.2 hosts, with VMX flag enabled in the guest?, Paolo Bonzini, 2019/01/18
- Re: [Qemu-devel] Live migration from Qemu 2.12 hosts to Qemu 3.2 hosts, with VMX flag enabled in the guest?, Dr. David Alan Gilbert, 2019/01/18
- Re: [Qemu-devel] Live migration from Qemu 2.12 hosts to Qemu 3.2 hosts, with VMX flag enabled in the guest?, Mark Mielke, 2019/01/22
- Re: [Qemu-devel] Live migration from Qemu 2.12 hosts to Qemu 3.2 hosts, with VMX flag enabled in the guest?, Daniel P . Berrangé, 2019/01/18
- Re: [Qemu-devel] Live migration from Qemu 2.12 hosts to Qemu 3.2 hosts, with VMX flag enabled in the guest?, Mark Mielke, 2019/01/18
- Re: [Qemu-devel] Live migration from Qemu 2.12 hosts to Qemu 3.2 hosts, with VMX flag enabled in the guest?, Daniel P . Berrangé, 2019/01/18