The Placement sync process involves some input from Placement first.
That is the UUID of the compute host RP. This is a remote call just like
the Placement updates we send later and it also may fail in all the
usual ways of remote calls. We need to fail the sync procedure if this
remote call fails.
Previously I had the mistaken belief that if I set the parent_uuid to
None that will be an invalid call rejected by Placement. But no, that's
a valid call and creates a resource provider without a parent. That is
the neutron managed resource providers will be in their own resource
provider tree instead of the compute host's resource provider tree.
In this change we make sure to handle the failure of getting the compute
host RP properly. We must not continue with the updates. And we must set
the agent's resources_synced to False.
Change-Id: Ie6ad33e2170c53a16c39a31a8d7f6496170a90ce
Closes-Bug: #1818683
732dbdaf5e