[openstack-dev] [nova] I think nova behaves poorly when booting multiple instances

Alexis Lee alexisl at hp.com
Tue Jun 2 10:28:03 UTC 2015

Andrew Laski said on Mon, Jun 01, 2015 at 09:26:33AM -0400:
> However what these parameters give users, versus orchestrating
> outside of Nova, is the ability to have the instances all scheduled
> as a single block.

We should seek to provide this via persistent claims. IE add to the
API something like:

    claim([ResourceRequest]): [ResourceClaim]
    boot(ResourceClaim, Image, ...): Instance
    free_claim([ResourceClaim]): None
    check_claim([ResourceRequest]): [Boolean]

(this is not a polished proposal!)

This allows you to claim() space for many instances, either in one API
call or across several, before beginning to boot instances. check_claim
is an obvious extension for probing availability.

Paul Murray tells me there was a blueprint for this some time ago, but
I can't find a spec for it. I'm interested in pushing this, I'll put up
a spec at some point unless someone beats me to it.

Nova Engineer, HP Cloud.  AKA lealexis, lxsli.

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