RHEL Engineering is moving the tracking of its product development work on RHEL 6 through RHEL 9 to Red Hat Jira (issues.redhat.com). If you're a Red Hat customer, please continue to file support cases via the Red Hat customer portal. If you're not, please head to the "RHEL project" in Red Hat Jira and file new tickets here. Individual Bugzilla bugs in the statuses "NEW", "ASSIGNED", and "POST" are being migrated throughout September 2023. Bugs of Red Hat partners with an assigned Engineering Partner Manager (EPM) are migrated in late September as per pre-agreed dates. Bugs against components "kernel", "kernel-rt", and "kpatch" are only migrated if still in "NEW" or "ASSIGNED". If you cannot log in to RH Jira, please consult article #7032570. That failing, please send an e-mail to the RH Jira admins at rh-issues@redhat.com to troubleshoot your issue as a user management inquiry. The email creates a ServiceNow ticket with Red Hat. Individual Bugzilla bugs that are migrated will be moved to status "CLOSED", resolution "MIGRATED", and set with "MigratedToJIRA" in "Keywords". The link to the successor Jira issue will be found under "Links", have a little "two-footprint" icon next to it, and direct you to the "RHEL project" in Red Hat Jira (issue links are of type "https://issues.redhat.com/browse/RHEL-XXXX", where "X" is a digit). This same link will be available in a blue banner at the top of the page informing you that that bug has been migrated.
Bug 1389313 - [DOC] Document that libvirt refuses to abort post-copy migrations
Summary: [DOC] Document that libvirt refuses to abort post-copy migrations
Keywords:
Status: CLOSED ERRATA
Alias: None
Product: Red Hat Enterprise Linux 7
Classification: Red Hat
Component: libvirt
Version: 7.3
Hardware: Unspecified
OS: Unspecified
unspecified
unspecified
Target Milestone: rc
: ---
Assignee: Jiri Denemark
QA Contact: Lili Zhu
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2016-10-27 12:41 UTC by Milan Zamazal
Modified: 2017-08-01 23:59 UTC (History)
5 users (show)

Fixed In Version: libvirt-3.2.0-1.el7
Doc Type: If docs needed, set a value
Doc Text:
Clone Of:
Environment:
Last Closed: 2017-08-01 17:19:14 UTC
Target Upstream Version:
Embargoed:

Attachments (Terms of Use)


Links
System ID Private Priority Status Summary Last Updated
Red Hat Product Errata RHEA-2017:1846 0 normal SHIPPED_LIVE libvirt bug fix and enhancement update 2017-08-01 18:02:50 UTC

Description Milan Zamazal 2016-10-27 12:41:21 UTC 
libvirt refuses to abort migrations in post-copy mode. However, this features is not properly documented in libvirt API reference documentation. virDomainMigrateStartPostCopy just mentions:

"On the other hand once the guest is running on the destination host, the migration can no longer be rolled back because none of the hosts has complete state. If this happens, libvirt will leave the domain paused on both hosts with VIR_DOMAIN_PAUSED_POSTCOPY_FAILED reason."

This is ambiguous and suggests that the migration might actually be aborted with a libvirt call and leave the VM in an inconsistent state. And virDomainAbortJob documentation doesn't mention anything about that at all.

It should be clearly documented that virDomainAbortJob won't abort a migration job in the post-copy mode (and returns with failure on such an attempt) and thus it's safe to call it regardless of the migration phase.
Comment 2 Jiri Denemark 2017-03-31 18:46:04 UTC 
Sent upstream for review: https://www.redhat.com/archives/libvir-list/2017-March/msg01702.html
Comment 3 Jiri Denemark 2017-03-31 19:51:03 UTC 
Pushed upstream as

commit 9e8164d2f9ee74e81aa558879f762712ec0c8ea1
Refs: v3.2.0-rc2-4-g9e8164d2f
Author:     Jiri Denemark <jdenemar>
AuthorDate: Fri Mar 31 20:41:39 2017 +0200
Commit:     Jiri Denemark <jdenemar>
CommitDate: Fri Mar 31 20:41:39 2017 +0200

    Document virDomainAbortJob behavior for post-copy migration

    https://bugzilla.redhat.com/show_bug.cgi?id=1389313

    Signed-off-by: Jiri Denemark <jdenemar>
Comment 5 Lili Zhu 2017-06-09 06:37:02 UTC 
The downstream doc /usr/share/doc/libvirt-docs-3.2.0/html/html/libvirt-libvirt-domain.html has been updated.
However, the upstream doc https://libvirt.org/html/libvirt-libvirt-domain.html
has not been updated.

Would you help to check it?
Comment 6 Jiri Denemark 2017-06-09 07:38:51 UTC 
Hmm, looks like the automatic docs updater on libvirt.org is broken. I'll check with DV.
Comment 7 Lili Zhu 2017-06-12 07:37:46 UTC 
As in http://libvirt.org/html/libvirt-libvirt-domain.html#virDomainAbortJob

The document has been updated as 
Requests that the current background job be aborted at the soonest opportunity. In case the job is a migration in a post-copy mode, virDomainAbortJob will report an error (see virDomainMigrateStartPostCopy for more details).


And also in http://libvirt.org/html/libvirt-libvirt-domain.html#virDomainMigrateStartPostCopy

Post-copy migration is guaranteed to converge since each page is transferred at most once no matter how fast it changes. On the other hand once the guest is running on the destination host, the migration can no longer be rolled back because none of the hosts has complete state. If this happens, libvirt will leave the domain paused on both hosts with VIR_DOMAIN_PAUSED_POSTCOPY_FAILED reason. It's up to the upper layer to decide what to do in such case. Because of this, libvirt will refuse to cancel post-copy migration via virDomainAbortJob.

As the documentation has been updated, hence, mark the bug as verified.
Comment 8 errata-xmlrpc 2017-08-01 17:19:14 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://access.redhat.com/errata/RHEA-2017:1846
Comment 9 errata-xmlrpc 2017-08-01 23:59:00 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://access.redhat.com/errata/RHEA-2017:1846
Note You need to log in before you can comment on or make changes to this bug.