In Pike (through change: I8d426f2635232ffc4b510548a905794ca88d7f99)
we started setting instance.avilability_zone during schedule time by
calculating the avz of the host into which the instance was scheduled
into. After this change was introduced, the metadata request for the avz
on the instance (through change: I73c3b10e52ab4cfda9dacc0c0ba92d1fcb60bcc9)
started using instance.get(availability_zone) instead of doing the upcall.
However this would return None for instances older than Pike whose
availability_zone was not mentioned during boot time as it would be set to
CONF.default_schedule_zone whose default value is None.
This patch adds an online_migration tool to populate missing
instance.availability_zone values.
Change-Id: I2a1d81bfeb1ea006c16d8f403e045e9acedcbe57
Closes-Bug: #1768876