Open Stack

Hi clint, matt.

To be noticed that post-copy and auto-convergence are mutually exclusive.

The drawbacks that we experienced with here is that live-migration using
either way post-copy or auto-convergence will likely fail for application
not being able to handle throttling. Although, post-copy is guaranteed to
work for most of your migration.

On the design part of your solution. For a while we had the same design
with each rack being segmented but we gave up with this choice as it was a
PITA especially for live-migration.

We’re currently migrating our network design to a much simplified all L3
network layout with our underlying network a bgp driven network and all
overlay network being managed by Openstack.

Let me know if you need more details or information.

Kind regards,
G.



Le mar. 7 août 2018 à 01:44, Matt Riedemann <mriedemos at gmail.com> a écrit :

> On 8/6/2018 8:12 AM, Clint Byrum wrote:
> > First a few facts about our installation:
> >
> > * We're using kolla-ansible and basically leaving most nova settings at
> > the default, meaning libvirt+kvm
> > * We will be using block migration, as we have no shared storage of any
> > kind.
> > * We use routed networks to set up L2 segments per-rack. Each rack is
> > basically an island unto itself. The VMs on one rack cannot be migrated
> > to another rack  because of this.
> > * Our main resource limitation is disk, followed closely by RAM. As
> > such, our main motivation for wanting to do live migration is to be able
> > to move VMs off of machines where over-subscribed disk users start to
> > threaten the free space of the others.
>
> What release are you on?
>
> >
> > * Do people have feedback on live_migrate_permit_auto_convergence? It
> > seems like a reasonable trade-off, but since it is defaulted to false, I
> > wonder if there are some hidden gotchas there.
>
> You might want to read through [1] and [2]. Those were written by the
> OSIC dev team when that still existed. But there are some (somewhat
> mysterious) mentions to caveats with post-copy you should be aware of.
> At this point, John Garbutt is probably the best person to talk to about
> those since all of the other OSIC devs that worked on this spec are long
> gone.
>
>  >
>  > * General pointers to excellent guides, white papers, etc, that might
> help us avoid doing all of our learning via trial/error.
>
> Check out [3]. I've specifically been meaning to watch the one from
> Boston that John was in.
>
> [1]
>
> https://specs.openstack.org/openstack/nova-specs/specs/pike/approved/live-migration-force-after-timeout.html
> [2]
>
> https://specs.openstack.org/openstack/nova-specs/specs/pike/approved/live-migration-per-instance-timeout.html
> [3] https://www.openstack.org/videos/search?search=live%20migration
>
> --
>
> Thanks,
>
> Matt
>
> _______________________________________________
> OpenStack-operators mailing list
> OpenStack-operators at lists.openstack.org
> http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-operators
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.openstack.org/pipermail/openstack-operators/attachments/20180807/45f79c00/attachment.html>