4:53 a.m.
Hello,
I recently upgraded our cluster from 4.3 to 4.5 (4.5.1.3-1.el8), I raised the cluster
compatibility afterwards to 4.7 as well. I noticed that the CPU hot plugging does not work
above 16 CPU's if cluster compatibility is set to 4.6 or 4.7.
Error I get is:
Failed to hot set number of CPUS to VM testVM-3. Underlying error message: invalid
argument: requested vcpus is greater than max allowable vcpus for the live domain: 32 >
16
Issue here I believe is that the MaxNumOfVmSockets values set on the engine per cluster
version is not correctly set on libvirt when VM is started.
My values on the engine:
MaxNumOfVmSockets: 32 version: 4.2
MaxNumOfVmSockets: 32 version: 4.3
MaxNumOfVmSockets: 32 version: 4.4
MaxNumOfVmSockets: 32 version: 4.5
MaxNumOfVmSockets: 64 version: 4.6
MaxNumOfVmSockets: 10000 version: 4.7
Values on libvirt for VM's for all cluster compatibility versions:
4.3
<vcpu placement='static' current='4'>32</vcpu>
4.4
<vcpu placement='static' current='4'>32</vcpu>
4.5
<vcpu placement='static' current='4'>32</vcpu>
4.6
<vcpu placement='static' current='4'>16</vcpu>
4.7
<vcpu placement='static' current='4'>16</vcpu>
Is anyone else experiencing this issue (possible BUG)?
Regards,
David
12:21 p.m.
New subject: Incorrect Max CPU's per VM in libvirt if cluster compatibility 4.6 or 4.7
"David Sekne" <david.sekne(a)gmail.com> writes:
Hello,
I recently upgraded our cluster from 4.3 to 4.5 (4.5.1.3-1.el8), I
raised the cluster compatibility afterwards to 4.7 as well. I noticed
that the CPU hot plugging does not work above 16 CPU's if cluster
compatibility is set to 4.6 or 4.7.
Error I get is:
Failed to hot set number of CPUS to VM testVM-3. Underlying error
message: invalid argument: requested vcpus is greater than max
allowable vcpus for the live domain: 32 > 16
Issue here I believe is that the MaxNumOfVmSockets values set on the
engine per cluster version is not correctly set on libvirt when VM is
started.
My values on the engine:
MaxNumOfVmSockets: 32 version: 4.2
MaxNumOfVmSockets: 32 version: 4.3
MaxNumOfVmSockets: 32 version: 4.4
MaxNumOfVmSockets: 32 version: 4.5
MaxNumOfVmSockets: 64 version: 4.6
MaxNumOfVmSockets: 10000 version: 4.7
Values on libvirt for VM's for all cluster compatibility versions:
4.3
<vcpu placement='static' current='4'>32</vcpu>
4.4
<vcpu placement='static' current='4'>32</vcpu>
4.5
<vcpu placement='static' current='4'>32</vcpu>
4.6
<vcpu placement='static' current='4'>16</vcpu>
4.7
<vcpu placement='static' current='4'>16</vcpu>
Is anyone else experiencing this issue (possible BUG)?
It's most likely a feature. Starting with 4.6, the maximum number of
vCPUs is limited because it consumes resources even if the CPUs are not
plugged in. Adjusting sockets/cores/threads configuration of the VM to
put more than one vCPU on a socket or changing MaxNumOfCpusCoefficient
config value should help in your case.
Regards,
Milan
1:35 a.m.
New subject: Incorrect Max CPU's per VM in libvirt if cluster compatibility 4.6 or 4.7
Hello,
Not sure about the feature part. I additionally tested this on oVirt 4.4.10.7-1.el8 and it
works fine even if cluster compatibility there is set to 4.6.
Engine:
MaxNumOfVmSockets: 32 version: 4.2
MaxNumOfVmSockets: 32 version: 4.3
MaxNumOfVmSockets: 32 version: 4.4
MaxNumOfVmSockets: 32 version: 4.5
MaxNumOfVmSockets: 32 version: 4.6
VM:
<vcpu placement='static' current='4'>32</vcpu>
Regards,
David
3:16 a.m.
New subject: Incorrect Max CPU's per VM in libvirt if cluster compatibility 4.6 or 4.7
"David Sekne" <david.sekne(a)gmail.com> writes:
Hello,
Not sure about the feature part. I additionally tested this on oVirt
4.4.10.7-1.el8 and it works fine even if cluster compatibility there
is set to 4.6.
Before oVirt 4.5, MaxNumOfCpusCoefficient was applied only if the
maximum number of the VM vCPU sockets was higher than 16. Now, it is
applied more strictly (although there are still some exceptions, which
is probably why you see 16 max vCPUs rather than 8). This means
MaxNumOfCpusCoefficient value cannot be ignored anymore in some
scenarios. If you need to hot plug more vCPUs than the number of the
initial vCPUs, you should change MaxNumOfCpusCoefficient.
Regards,
Milan
Engine:
MaxNumOfVmSockets: 32 version: 4.2
MaxNumOfVmSockets: 32 version: 4.3
MaxNumOfVmSockets: 32 version: 4.4
MaxNumOfVmSockets: 32 version: 4.5
MaxNumOfVmSockets: 32 version: 4.6
VM:
<vcpu placement='static' current='4'>32</vcpu>
Regards,
David
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4 a.m.
New subject: Incorrect Max CPU's per VM in libvirt if cluster compatibility 4.6 or 4.7
Hello,
To confirm, changing MaxNumOfCpusCoefficient solved my issue.
<vcpu placement='static' current='4'>64</vcpu>
Thank you for the help.
Regards,
David
890
days inactive
891
days old
4 comments
2 participants
participants (2)
-
David Sekne -
Milan Zamazal