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Oversubscription of cores in compute nodes

asked 2011-05-31 10:43:42 -0500

diego-parrilla-santamaria gravatar image

Hi all openstackers,

I have been playing a bit with the information stored in the 'compute_nodes' table, trying to cheat Nova about the number of virtual cores available in the compute nodes. It seems that this table is not read by the scheduler, instead, the scheduler only computes the values retrieved from the compute nodes directly.

Basically my goal is to oversubscribe the number of cores of the compute nodes. I'm using KVM and I would like to decide how many virtual cores are available in each node. I have read about the get_hosts_stats() and the periodic_tasks(), but I was wondering if there is a way to manually configure the number of virtual cores per node and avoid rewriting this function.

Example: My server says it has 16 cores, but I want to implement an oversubscription ratio of 1:4, obtaining 64 virtual cores that will operate in a range of Mhz depending on how busy the real cores are.

Regards Diego

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answered 2011-05-31 17:59:07 -0500

vishvananda gravatar image

If you are using simple scheduler, you can just up the --max_cores flag on the scheduler host.

Vish

On May 31, 2011, at 3:45 AM, Diego Parrilla wrote:

New question #159723 on OpenStack Compute (nova): https://answers.launchpad.net/nova/+q...

Hi all openstackers,

I have been playing a bit with the information stored in the 'compute_nodes' table, trying to cheat Nova about the number of virtual cores available in the compute nodes. It seems that this table is not read by the scheduler, instead, the scheduler only computes the values retrieved from the compute nodes directly.

Basically my goal is to oversubscribe the number of cores of the compute nodes. I'm using KVM and I would like to decide how many virtual cores are available in each node. I have read about the get_hosts_stats() and the periodic_tasks(), but I was wondering if there is a way to manually configure the number of virtual cores per node and about rewriting this function.

Example: My server says it has 16 cores, but I want to implement an oversubscription ratio of 1:4, obtaining 64 virtual cores that will operate in a range of Mhz depending on how busy the real cores are.

Regards Diego


You received this question notification because you are a member of Nova Core, which is an answer contact for OpenStack Compute (nova).

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Asked: 2011-05-31 10:43:42 -0500

Seen: 336 times

Last updated: May 31 '11