[live migration] The instance's task status is pending on migrating

[Dave Chen]

I am trying to migrate the instance to another compute node, but enter a wrong host name accidentally, after running the below commands,
$ nova live-migration 7ff75fa0-f88d-4bfd-8ef2-632e01f04bb9 $FAKE_HOST

Now the instance is pending on migration, and even cannot migration with the *correct* destination host anymore, this is a bug I found in the N stable release, but I believe the bug also exist in the O or master branch.

The logs,

^[[01;31m2017-03-09 03:12:03.541 TRACE nova.api.openstack.extensions ^[[01;35m^[[00m File "/opt/stack/nova/nova/objects/compute_node.py", line 503, in get_all_by_host
^[[01;31m2017-03-09 03:12:03.541 TRACE nova.api.openstack.extensions ^[[01;35m^[[00m use_slave=use_slave)
^[[01;31m2017-03-09 03:12:03.541 TRACE nova.api.openstack.extensions ^[[01;35m^[[00m File "/opt/stack/nova/nova/db/sqlalchemy/api.py", line 225, in wrapper
^[[01;31m2017-03-09 03:12:03.541 TRACE nova.api.openstack.extensions ^[[01;35m^[[00m return f(*args, **kwargs)
^[[01;31m2017-03-09 03:12:03.541 TRACE nova.api.openstack.extensions ^[[01;35m^[[00m File "/opt/stack/nova/nova/objects/compute_node.py", line 498, in _db_compute_node_get_all_by_host
^[[01;31m2017-03-09 03:12:03.541 TRACE nova.api.openstack.extensions ^[[01;35m^[[00m return db.compute_node_get_all_by_host(context, host)
^[[01;31m2017-03-09 03:12:03.541 TRACE nova.api.openstack.extensions ^[[01;35m^[[00m File "/opt/stack/nova/nova/db/api.py", line 278, in compute_node_get_all_by_host
^[[01;31m2017-03-09 03:12:03.541 TRACE nova.api.openstack.extensions ^[[01;35m^[[00m return IMPL.compute_node_get_all_by_host(context, host)
^[[01;31m2017-03-09 03:12:03.541 TRACE nova.api.openstack.extensions ^[[01;35m^[[00m File "/opt/stack/nova/nova/db/sqlalchemy/api.py", line 270, in wrapped
^[[01;31m2017-03-09 03:12:03.541 TRACE nova.api.openstack.extensions ^[[01;35m^[[00m return f(context, *args, **kwargs)
^[[01;31m2017-03-09 03:12:03.541 TRACE nova.api.openstack.extensions ^[[01;35m^[[00m File "/opt/stack/nova/nova/db/sqlalchemy/api.py", line 667, in compute_node_get_all_by_host
^[[01;31m2017-03-09 03:12:03.541 TRACE nova.api.openstack.extensions ^[[01;35m^[[00m raise exception.ComputeHostNotFound(host=host)
^[[01;31m2017-03-09 03:12:03.541 TRACE nova.api.openstack.extensions ^[[01;35m^[[00mComputeHostNotFound: Compute host $fake could not be found.

change back to the correct hostname, now it says,
$ nova live-migration 6714b056-4950-4e63-83d3-fc383e977a53 openstack-dev
ERROR (Conflict): Cannot 'os-migrateLive' instance 6714b056-4950-4e63-83d3-fc383e977a53 while it is in task_state migrating (HTTP 409) (Request-ID: req-ed017800-37c0-4419-b533-3b52fba6b290)

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/443509

[Sivasathurappan Radhakrishnan (siva-radhakrishnan)]

This is one seems to be a duplicate of this bug https://bugs.launchpad.net/nova/+bug/1643623

[OpenStack Infra (hudson-openstack)]

Change abandoned by Dave Chen (<email address hidden>) on branch: master
Review: https://review.openstack.org/443509
Reason: This has been duplicated with https://review.openstack.org/#/c/401009/