KVM GUEST STARTUP FAIL WITH UNSUPPORTED CONFIGURATION: VNUMA: FAILED TO RENDER AUTO VNUMA TOPOLOGY FOR GUEST (Doc ID 2925722.1)

Last updated on JUNE 28, 2023

Applies to:

Symptoms

This issue is reported on Exadata X9M-2 with kvmhost1(X9-2) running ESS image 21.2.10.0.0.220317 and OS kernel 4.14.35-2047.511.5.5.el7uek
libvirt version: 5.7.0, package: 32.el7

Post CPU upgrade on KVMHost (kvmhost1), Guest (kvmguest1) would not startup. Startup fails with:

[root@kvmhost1 libvirt.backup]# virsh start kvmguest1.abc.d
error: failed to get domain 'kvmguest1.abc.d'

'virsh' would not list any guest as well (in this case, only one guest was configured on the host).

[root@kvmhost1 tmp]# virsh list

Id Name State
--------------------

Extracting guest definition also fails with vNUMA error:

[root@kvmhost1 qemu]# virsh define kvmguest1.abc.d.xml
error: Failed to define domain from kvmguest1.abc.d.xml
error: unsupported configuration: vNUMA: failed to render auto vNUMA topology
for guest 'kvmguest1.abc.d.xml' because the configured 62 vCPUs do not match
the host's 2 NUMA nodes to produce an evenly balanced CPU topology.

Manually setting up vCPU count using 'virsh' does not help either:

[root@kvmhost1 GuestImages]# virsh setvcpus kvmguest1.abc.d 124 --maximum --config
error: failed to get domain 'kvmguest1.abc.d'

Changes

CPU was upgraded on KVM Host: From 1-socket (32 CPU cores) to 2-sockets (64 CPU cores), thus increasing total vCPUs from 64 to 128

Before:

DBMCLI> LIST DBSERVER attributes coreCount
32/32

After:

DBMCLI> LIST DBSERVER attributes coreCount
64/64

$grep -i 'physical id' cpuinfo|sort|uniq
physical id : 0
physical id : 1 <<----
$
$grep -i 'cpu cores' cpuinfo|sort|uniq
cpu cores : 32 <<-- this is per socket
$
$grep -i processor cpuinfo|wc -l
128

NUMA configuration on the host would look fine :

$cat numactl_--hardware
available: 2 nodes (0-1)
node 0 cpus: 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
25 26 27 28 29 30 31 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82
83 84 85 86 87 88 89 90 91 92 93 94 95
node 0 size: 257110 MB
node 0 free: 19342 MB
node 1 cpus: 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52
53 54 55 56 57 58 59 60 61 62 63 96 97 98 99 100 101 102 103 104 105 106 107
108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127
node 1 size: 258034 MB
node 1 free: 21521 MB
node distances:
node 0 1
0: 10 20
1: 20 10

Cause

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