Bad libvirt version 1.2.21 when doing live migration

[Eli Qiao]

Description of problem:

Unable to change target guest XML during migration, the argument dxml in virDomainMigrateToURI2 is not used in libvirt 1.2.21

check https://bugzilla.redhat.com/show_bug.cgi?id=1295405

Bug is fixed by libvirt 1.3.1: Jan 17 2016

check http://libvirt.org/news.html

libvirt-domain: fix dxml passing in virDomainMigrateToURI2 (Ján Tomko)

So we need to blacklist libvirt 1.2.21 when using virDomainMigrateToURI2

[Kashyap Chamarthy (kashyapc)]

Looks like it was an inadvertent omission in the upstream libvirt patch: "The refactoring in commit a26669d silently ignored the dxml
parameter of virDomainMigrateToURI2."[1]

Lee Yarwood has pointed out on #openstack-nova that there are past instances where we've blacklisted specific buggy libvirt versions. E.g. take a look here[2]. So something similar could be done in this case, too.

[1] https://www.redhat.com/archives/libvir-list/2016-January/msg00058.html
[2] https://github.com/openstack/nova/blob/master/nova/virt/libvirt/driver.py#L5229,L5238

[Lee Yarwood (lyarwood)]

Actually this isn't going to be required, the only time we use migrateToURI2 at present is with libvirt versions prior to 1. 2.17 [1], for all versions after this we use migrateToURI3 [2]. IMHO we can close this out.

[1] https://git.io/vw2ao
[2] https://git.io/vw2aa

[Lee Yarwood (lyarwood)]

Closing this out as WONTFIX assuming that only migrateToURI3 will continue to be used for libvirt versions >= 1.2.17

[Kashyap Chamarthy (kashyapc)]

Yep, agreed with comment#3, on a closer look[1], indeed migrateToURI3() is used for any version above or equals 1.2.17.

Thanks, Lee!

[1] https://github.com/openstack/nova/blob/a4e15e329f9adbcfe72fbcd6acb94f0743ad02f8/nova/virt/libvirt/driver.py#L6076-L6094

[Eli Qiao (taget-9)]

Make sense.