There is a unique index on the compute_nodes.uuid column which
means we can't have more than one compute_nodes record in the
same DB with the same UUID even if one is soft deleted because
the deleted column is not part of that unique index constraint.
This is a problem with ironic nodes where the node is 1:1 with
the compute node record, and when a node is undergoing maintenance
the driver doesn't return it from get_available_nodes() so the
ComputeManager.update_available_resource periodic task (soft)
deletes the compute node record, but when the node is no longer
under maintenance in ironic and the driver reports it, the
ResourceTracker._init_compute_node code will fail to create the
ComputeNode record again because of the duplicate uuid.
This change handles the DBDuplicateEntry error in compute_node_create
by finding the soft-deleted compute node with the same uuid and
simply updating it to no longer be (soft) deleted.
Closes-Bug: #1839560
Change-Id: Iafba419fe86446ffe636721f523fb619f8f787b3
(cherry picked from commit 8b007266f4)
1b02166528