Bug 1180521

Summary:	Domain restore fails from a saved state in a file with xml option.
Product:	Red Hat Enterprise Linux 6	Reporter:	Jan Kurik <jkurik>
Component:	libvirt	Assignee:	Ján Tomko <jtomko>
Status:	CLOSED ERRATA	QA Contact:	Virtualization Bugs <virt-bugs>
Severity:	medium	Docs Contact:
Priority:	medium
Version:	6.3	CC:	acathrow, cwei, dallan, dyuan, gsun, jdenemar, jsuchane, jtomko, leiwan, lhuang, michal.skrivanek, mzhan, pkrempa, pm-eus, rbalakri, rhodain, shyu, zhwang
Target Milestone:	rc	Keywords:	Reopened, Upstream, ZStream
Target Release:	---
Hardware:	x86_64
OS:	Linux
Whiteboard:
Fixed In Version:	libvirt-0.10.2-46.el6_6.3	Doc Type:	Bug Fix
Doc Text:	Cause: Libvirtd converted the user-specified domain XML to migratable form before comparing it against the domain XML stored in the save file, but for external snapshots, non-migratable XML was stored in the save file. Consequence: Restore from an external snapshot with user-specified XML was impossible, because it failed the ABI stability check. Fix: Use migratable XML in save files for external snapshots as well to fix this for new saves. Do the ABI stability check against the user-specified XML directly if it fails against the migratable form, to allow restoring saves from older libvirt. Result: Restore works with XML in both migratable and non-migratable form.	Story Points:	---
Clone Of:	834196	Environment:
Last Closed:	2015-01-30 21:13:38 UTC	Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:	834196
Bug Blocks:

Description Jan Kurik 2015-01-09 10:52:09 UTC

This bug has been copied from bug #834196 and has been proposed
to be backported to 6.6 z-stream (EUS).

Comment 5 Luyao Huang 2015-01-28 07:58:45 UTC

I can reproduce this issue with libvirt-0.10.2-46.el6.x86_64:

1. # virsh dumpxml r6
    <controller type='usb' index='0'>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x01' function='0x2'/>
    </controller>
    <controller type='ccid' index='0'/>

2. # virsh start r6

3.# virsh dumpxml r6 > r6.xml
4.# virsh dumpxml r6 --migratable > r6mig.xml

5.edit r6.xml and r6mig.xml and change disk path to /tmp/r6.img
# vim r6mig.xml
# vim r6.xml

6.# virsh save r6 r6.save --xml r6.xml

Domain r6 saved to r6.save

7. check the r6.save if the disk path have been changed:

# vim r6.save

8. restore vm and will failed with r6.xml:

# virsh restore r6.save --xml r6.xml
error: Failed to restore domain from r6.save
error: unsupported configuration: Target controller type usb does not match source ccid

# virsh restore r6.save --xml r6mig.xml
Domain restored from r6.save

And verify this issue with libvirt-0.10.2-46.el6_6.3.x86_64:

1. update libvirt to libvirt-0.10.2-46.el6_6.3.x86_64 and use old save file test:
# yum update libvirt*

2.# virsh restore r6.save --xml r6.xml
Domain restored from r6.save

3.# virsh destroy r6
Domain r6 destroyed

4.# virsh restore r6.save --xml r6mig.xml
Domain restored from r6.save

5. retest with the reproduce steps:

# virsh start r6

# virsh dumpxml r6 > r6.xml
# virsh dumpxml r6 --migratable > r6mig.xml

6.edit r6.xml and r6mig.xml and change disk path to /tmp/r6.img
# vim r6mig.xml
# vim r6.xml

7.save 
# virsh save r6 r6.save --xml r6.xml
Domain r6 saved to r6.save

8.restore
# virsh restore r6.save --xml r6.xml
Domain restored from r6.save

# virsh destroy r6
Domain r6 destroyed

# virsh restore r6.save --xml r6mig.xml
Domain restored from r6.save

And also test with snapshot (although we do not support it).

But i found this cannot work when vm use:
  <cpu mode='host-passthrough'>
  </cpu>

# virsh dumpxml r6 > r6.xml
# vim r6.xml (change path to /tmp/r6)
# virsh save r6 r6.save --xml r6.xml

Domain r6 saved to r6.save

# virsh restore r6.save --xml r6.xml
error: Failed to restore domain from r6.save
error: unsupported configuration: Target CPU model (null) does not match source SandyBridge

And also found this issue with rhel7.1 (and i think maybe the same with bug 1183869)

Comment 6 Luyao Huang 2015-01-28 08:03:13 UTC

Hi Jan,

Would you please help me to checkout if steps in comment 5 is ok to verify this bug? and is the last issue i met is a issue need fix in rhel6? 

Thanks in advance for your answer.

Comment 7 Ján Tomko 2015-01-28 17:59:39 UTC

The verification steps are correct.

I don't think restore with XML that wasn't generated with --migratable or --update-cpu is worth fixing in RHEL 6.

Comment 8 Luyao Huang 2015-01-29 00:35:27 UTC

(In reply to Jan Tomko from comment #7)
> The verification steps are correct.
> 
> I don't think restore with XML that wasn't generated with --migratable or
> --update-cpu is worth fixing in RHEL 6.

Thanks for your reply and verify this bug with comment 5

Comment 10 errata-xmlrpc 2015-01-30 21:13:38 UTC

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://rhn.redhat.com/errata/RHBA-2015-0106.html