[openstack-dev] [nova] Thoughs please on how to address a problem with mutliple deletes leading to a nova-compute thread pool problem

Clint Byrum clint at fewbar.com
Mon Oct 28 16:29:29 UTC 2013


Excerpts from Joshua Harlow's message of 2013-10-28 09:01:44 -0700:
> Except I think the CAP theorem would say that u can't accurately give back there quota under thing like network partitions.
> 
> If nova-compute and the message queue have a network partition then u can release there quota but can't actually delete there vms. I would actually prefer to not release there quota, but then this should be a deployer decision and not a one size fits all decision (IMHO).
> 

CAP encourages convergence models to satisfy problems with consistency.
Quotas and records of allocated resources are records of intention and
we can converge the physical resources with the expressed intentions
later. The speed with which you do that is part of the cost of network
partition failures and should be considered when assessing and mitigating
risk.

It is really bad customer service to tell somebody "Yes I know you've
asked me to stop charging you, but my equipment has failed so I MUST
keep charging you." Reminds me of that gym membership I tried to
cancel... _TRIED_.



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