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Hi all,

I'd like to bring up this matter again, although it was at some extent 
discussed during the recent summit.

The problem arises from the fact that the functionality exposing device 
names for usage through public APIs is deteriorating in nova. It's being 
deliberately removed because as I understand, it doesn't universally and 
consistently work in all of the backends. It happens  since IceHouse and 
introduction of bdm v2. The following very recent review is one of the 
ongoing efforts in this direction:
https://review.openstack.org/#/c/185438/

The reason for my concern is that EC2 API have some important cases 
relying on this information (some of them have no workarounds). Namely:
1. Change of parameters set by image for instance booting.
2. Showing instance's devices information by euca2ools.
3. Providing additional volumes for instance booting
4. Attaching volume
etc...

Related to device names and additional related features we have troubles 
with now:
1. All device name related features
2. Modification of deleteOnTermination flag
3. Modification of parameters for instance booting
4. deleteOnTermination and size of volume aren't stored into instance 
snapshots now.

Discussions during the summit on the matter were complicated because 
nobody present really understood in details why and what is happening 
with this functionality in nova. It was decided though, that overall 
direction would be to add necessary features or restore them unless 
there is something really showstopping:
https://etherpad.openstack.org/p/YVR-nova-contributor-meetup

As I understand, Nikola Depanov is the one working on the matter for 
some time obviously is the best person who can help to resolve the 
situation. Nikola, if possible, could you help with it and clarify the 
issue.

My suggestion, based on my limited knowledge at the moment, still is to 
restore back or add all of the necessary APIs and provide tickets or 
known issues for the cases where the functionality is suffering from the 
backend limitations.

Please let me know what you think.

Best regards,
   Alex Levine