live migration doesn't work for VMs in rescued state

Bug #1305062 reported by Loganathan Parthipan on 2014-04-09
This bug affects 4 people
Affects Status Importance Assigned to Milestone
OpenStack Compute (nova)

Bug Description

I'd expect live-migration to migrate instances in rescued state as they're online VMs anyway, as opposed to those that are shutoff or suspended. However, I see that it's currently disabled in the compute API.

nova live-migration --block-migrate b32b0eb4-b8aa-4204-b104-61e733839227 overcloud-novacompute0-aipxwbabgq7a
ERROR: Cannot 'os-migrateLive' while instance is in vm_state rescued (HTTP 409) (Request-ID: req-5eea8f1c-5602-4d48-9690-929baff3b560)

This is stopped by this decorator:

    def live_migrate(self, context, instance, block_migration,

However, there are more to it than fixing the decorator.

Should we treat this as a feature or bugfix?

Changed in nova:
assignee: nobody → Loganathan Parthipan (parthipan)
Daniel Berrange (berrange) wrote :

For paused VMs this is certainly a bug - there's no reason to restrict this for paused VMs.

For rescued VMs, it is a little more complicated, but again the VM is "active" from the POV of the user so I'd expect migrate to be allowe & o succeed.

Tracy Jones (tjones-i) on 2014-04-09
tags: added: compute
Changed in nova:
status: New → Confirmed

Fix proposed to branch: master

Changed in nova:
status: Confirmed → In Progress

Change abandoned by Sean Dague (<email address hidden>) on branch: master
Reason: this has not addressed comments in over 1.5 months, abandoning

Upstream patch stalled

Changed in nova:
status: In Progress → Confirmed
importance: Undecided → Medium
assignee: Loganathan Parthipan (parthipan) → nobody
Changed in nova:
assignee: nobody → Matthew Gilliard (matthew-gilliard-u)

I have agreed with Parthipan that I will continue his fix. I would like to confirm with Dan Berrange and others whether the approach taken there is still correct. Thanks.

Changed in nova:
status: Confirmed → In Progress

Fix proposed again.

Submitter: Jenkins
Branch: master

commit 22dde6e56b2d93d9aa3776952eb7fc0792e220dc
Author: Loganathan Parthipan <email address hidden>
Date: Mon Dec 15 14:23:18 2014 +0000

    Support live-migrate of instances in PAUSED state

    Live migration enables one to migrate an active VM that consumes
    system resources such as memory and CPU.

    Nova currently allows only those in ACTIVE vm_state to migrate. This
    patch adds support for PAUSED vm_state. Essentially a paused state is
    identical to a running state except the stopped CPUs.

    Co-Author: "Matthew Gilliard <email address hidden>"

    Partial-Bug: #1305062
    Change-Id: Ib38eaf412cb51a9cbfc443c5ec15c5797265ddae

Here is doc related to vm states and transitions:

Do you think, that this change has impact on this doc ?

tags: added: live-migrate

Matthew, do you also work on LM of VMs in rescued state?

Hi Pawel

   Yes, I expect to have a patch up for this soon (next couple of
weeks). It's a more complicated case though, sadly.


On 02/04/15 13:46, Pawel Koniszewski wrote:
> Matthew, do you also work on LM of VMs in rescued state?

summary: - live migration doesn't work for VMs in paused or rescued states
+ live migration doesn't work for VMs in rescued state
description: updated
Changed in nova:
assignee: Matthew Gilliard (matthew-gilliard-u) → nobody
Changed in nova:
status: In Progress → Confirmed
Paul Murray (pmurray) on 2015-11-06
tags: added: live-migration
removed: live-migrate
lvmxh (shaohef) on 2015-11-17
Changed in nova:
assignee: nobody → lvmxh (shaohef)
lvmxh (shaohef) on 2015-12-03
Changed in nova:
assignee: lvmxh (shaohef) → nobody
Sujitha (sujitha-neti) on 2016-01-21
Changed in nova:
assignee: nobody → Sujitha (sujitha-neti)
Sujitha (sujitha-neti) wrote :

Allowing live migration for rescue state would come under feature enhancement. So I think it has to be moved to Wishlist.

Changed in nova:
assignee: Sujitha (sujitha-neti) → nobody
John Garbutt (johngarbutt) wrote :

This feels like a bug fix.

Changed in nova:
importance: Medium → Wishlist
stgleb (gstepanov) on 2016-03-14
Changed in nova:
assignee: nobody → stgleb (gstepanov)

After double-checking with danpb this is still a valid bug report and
it should be fixed for rescued instances.

Dear assignee, please provide a (WIP) patch in the next weeks. If you
stop working on this report, please remove yourself as assignee and
switch the status back. If you need assistance, reach out on the
IRC channel #openstack-nova or use the mailing list.

Changed in nova:
importance: Wishlist → Medium
status: Confirmed → In Progress
Sean Dague (sdague) wrote :

There are no currently open reviews on this bug, changing
the status back to the previous state and unassigning. If
there are active reviews related to this bug, please include
links in comments.

Changed in nova:
status: In Progress → Confirmed
assignee: stgleb (gstepanov) → nobody
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