nova shouldn't error if we can't schedule all of max_count instances at boot time

[Chris Friesen]

When booting up instances, nova allows the user to specify a "min count" and a "max count".

Currently, if the user has quota space for "max count" instances, then nova will try to create them all. If any of them can't be scheduled, then the creation of all of them will be aborted and they will all be put into an error state.

Arguably, if nova was able to schedule at least "min count" instances (which defaults to 1) then it should continue on with creating those instances that it was able to schedule. Only if nova cannot create at least "min count" instances should nova actually consider the request as failed.

And I think that if nova can't schedule "max count" instances, but can schedule at least "min count" instances, then it shouldn't put the others into an error state--it should be like they never actually existed.

[Sean Dague (sdague)]

This is really a feature as it changes quite substantially how the bulk create works and is accounted for. This should really come in as a spec I think.

[Chris Friesen (cbf123)]

For what it's worth, I've confirmed that this is still an issue as of Nov 12, 2016.

[Sai Sindhur Malleni (smalleni)]

Still an issue in Ocata.

[Jason Anderson (jasonandersonatuchicago)]

Still an issue in Rocky.