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[nova] NUMA scheduling


As far as I know, numa_nodes=1 just means --> the resources for that VM
should run on one NUMA node (so either NUMA0 or NUMA1). If there is space
free on both, then it's probably going to pick one of the two?

On Fri, Oct 16, 2020 at 6:56 PM Eric K. Miller <emiller at genesishosting.com>
wrote:

> Hi,
>
>
>
> I'm at a loss for finding good information about how a VM's vCPUs and
> Memory are assigned to NUMA nodes within a scheduled physical host.  I
> think Libvirt does this, and the Nova Scheduler simply finds the right
> physical host to run the VM, and thus Nova has no input on which NUMA node
> to choose.  So this might be a Libvirt question.
>
>
>
> We are running Stein and have the issue where VMs launch on NUMA Node 0,
> and not on NUMA Node 1, in physical hosts with two processors, and are
> simply looking for a way to tell Libvirt to consider NUMA Node 1 when
> scheduling a VM, since there is nearly all of the memory available on NUMA
> Node 1.
>
>
>
> Our flavors are defined with hw:numa_nodes='1' since we want all
> vCPUs+Memory to land on a single NUMA Node, and so the guest OS has
> visibility that a single NUMA Node is being used.
>
>
>
> We are "not" looking for a way to pin a VM to a specific NUMA node (such
> as for SR-IOV purposes).
>
>
>
> Any suggestions where to look for the solution?
>
>
>
> Thanks!
>
>
> Eric
>
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