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On 04/09/2015 10:13 PM, Monty Taylor wrote:
> On 04/09/2015 02:40 PM, Timur Sufiev wrote:
>> Hello!
>>
>> While analyzing Horizon behavior on a large scale we faced some performance
>> issues which are most probably caused by inefficient calls to Nova API from
>> Horizon, more specifically described at
>> https://bugs.launchpad.net/nova/+bug/1442310
>>
>> Since my knowledge of Nova existing APIs is not very comprehensive I am not
>> quite sure whether current Nova API indeed doesn't support requesting the
>> details of a multiple instances limited by their <instance_id>-s (passed as
>> part of `search_opts` parameter) or I just failed to find the proper REST
>> call at http://developer.openstack.org/api-ref-compute-v2.1.html
>>
>> Nova developers, could you please help me on that matter?
>
> I recommend not trying to do any of that - but instead doing a 'list' to
> get the entire set of data and then filtering out the things you don't
> want client side.

The current code does what you recommend, but as mentioned in the bug report 
listed above they've run into performance issues.

They want to show the names for instances that cinder volumes are attached to, 
or that have floating IP addresses.  Currently the retrieve the entire list of 
instances in order to get the names of the (potentially much smaller) set of 
instances that they actually care about.

If there was a "give me info on these specific instances" command in the nova 
API the above scenarios would be more efficient.

Chris