Similar capabilities are being introduced here:


From:   Kenichi Oomichi <>
To:     "OpenStack Development Mailing List (not for usage questions)" 
Date:   03/02/2014 11:48 AM
Subject:        [openstack-dev] [Nova] bp: nova-ecu-support


There is a blueprint ECU[1], and that is an interesting idea for me.
so I'd like to know the comments about ECU idea.

After production environments start, the operators will need to add
compute nodes before exhausting the capacity.
On the scenario, they'd like to add cost-efficient machines as the
compute node at the time. So the production environments will consist
of different performance compute nodes. Also they hope to provide
the same performance virtual machines on different performance nodes
if specifying the same flavor.

Now nova contains flavor_extraspecs[2] which can customize the cpu
bandwidth for each flavor:
 # nova flavor-key m1.low_cpu set quota:cpu_quota=10000
 # nova flavor-key m1.low_cpu set quota:cpu_period=20000

However, this feature can not provide the same vm performance on
different performance node, because this arranges the vm performance
with the same ratio(cpu_quota/cpu_period) only even if the compute
node performances are different. So it is necessary to arrange the
different ratio based on each compute node performance.

Amazon EC2 has ECU[3] already for implementing this, and the blueprint
[1] is also for it.

Any thoughts?

Ken'ichi Ohmichi


[3]:  "Q: What is a “EC2 Compute Unit” 
and why did you introduce it?"

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