Open Stack

On 7/23/15, 8:54 AM, "Carl Baldwin" <carl at ecbaldwin.net> wrote:

>On Thu, Jul 23, 2015 at 8:51 AM, Kevin Benton <blak111 at gmail.com> wrote:
>>>Or, migration scheduling would need to respect the constraint that a
>> port may be confined to a set of hosts.  How can be assign a port to a
>> different network?  The VM would wake up and what?  How would it know
>> to reconfigure its network stack?
>>
>> Right, that's a big mess. Once a network is picked for a port I think we
>> just need to rely on a scheduler filter that limits the migration to 
>>where
>> that network is available.
>
>+1.  That's where I was going.

Agreed, this seems reasonable to me for the migration scheduling case.

I view the pre-created port scenario as an edge case.  By explicitly 
pre-creating a port and using it for a new instance (rather than letting 
nova create a port for you), you are implicitly stating that you have more 
knowledge about the networking setup.  In so doing, you’re removing the 
guard rails (of nova scheduling the instance to a good network for the 
host it's on), and therefore are at higher risk to crash and burn.  To me 
that’s an acceptable trade-off.

Mike