Description of problem:
The Filter AggregateInstanceExtraSpecsFilter returned 0 hosts.

The reason behind was name of compute node(DNUCS002-osd-compute-0.localdomain) added in the host-aggregate. The node name given was in capital letter when we re-attached the compute node to the host aggregate with name in small letter( dnucs002-osd-compute-0.localdomain) as mentioned in nova hypervisor-list, it works fine. 

cu want that the compute name should be case insensitive in this case, if not then while adding the compute node to the host aggregate it should throw the error with proper message like 'compute host not found'.

It is confusing that node successfully attached to the hostaggregate, however while spawning the instance the filter simply return 0 hosts without any clue.  


[stack@dnucs002-ospd ~]$ nova hypervisor-list
+----+------------------------------------+-------+---------+
| ID | Hypervisor hostname                | State | Status  |
+----+------------------------------------+-------+---------+
| 1  | dnucs002-osd-compute-0.localdomain | up    | enabled |
| 4  | dnucs002-compute-3.localdomain     | up    | enabled |


[stack@dnucs002-ospd ~]$ openstack aggregate show 2
+-------------------+-----------------------------------------+
| Field             | Value                                   |
+-------------------+-----------------------------------------+
| availability_zone | mgmt                                    |
| created_at        | 2017-06-12T19:48:03.000000              |
| deleted           | False                                   |
| deleted_at        | None                                    |
| hosts             | [u'DNUCS002-osd-compute-0.localdomain'] |


Version-Release number of selected component (if applicable):


How reproducible:


Steps to Reproduce:
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Actual results:
The Filter AggregateInstanceExtraSpecsFilter returned 0 hosts.

Expected results:

It should returned the hosts attached to the hostaggregate

Additional info: