Open Stack

On 05/28/2015 09:25 PM, Jay Pipes wrote:
> On 05/26/2015 03:13 AM, Daniel P. Berrange wrote:
>> On Sat, May 23, 2015 at 11:00:32AM +0200, Géza Gémes wrote:
>>> Hi,
>>>
>>> When someone calls nova volume-attach or the block-device-mapping parameter
>>> at boot, it is possible to specify a device name for the guest. However I
>>> couldn't find any guest OS which would honor this. E.g. with libvirt/kvm, if
>>> the guest has two virtio disks already (vda and vdb), specifying vdf would
>>> be ignored and the disk will be attached as vdc in the guest.
>>> I propose to deprecate this option and at boot where it is not optional to
>>> accept only auto as an option.
>>
>> This was a design mistake in the original API which we can't now remove
>> without breaking backcompatibility. While it is still supported, many
>> hypervisors will completely ignore it, so we discourage people from ever
>> using it. Just allow the hypervisor and/or guest OS to pick the device
>> name
>
> While Dan is correct that we cannot just remove the parameter from the Nova API,
> we *can* add a microversion that removes the parameter from the accepted list of
> parameters for POST /servers and returns an error when the client has sent both
> an X-OpenStack-Compute-API-Version value >= the microversion increment *and* the
> device name parameter.

And presumably this would require a spec because it touches the API.  (Should be 
a simple one though since the change is trivial.)

Chris