Comment 6 for bug 1959328

I tracked the following:

Tempest failed test: tempest.scenario.test_network_basic_ops.TestNetworkBasicOps.test_network_basic_ops

tempest run log: empest.exceptions.BuildErrorException: Server 7222b8b5-1e07-4589-b9f7-eab775f0f046 failed to build and is in ERROR status
    Details: {'code': 500, 'created': '2022-02-21T14:56:14Z', 'message': 'Exceeded maximum number of retries. Exhausted all hosts available for retrying build failures for instance 7222b8b5-1e07-4589-b9f7-eab775f0f046.'}

Searching with the server uuid in nova-conductor.log.txt.gz on overcloud node:
error: process exited while connecting to monitor: 2022-02-21T14:56:11.787865Z qemu-kvm: Cannot load certificate '/etc/pki/libvirt-vnc/server-cert.pem' & key '/etc/pki/libvirt-vnc/server-key.pem': Error while reading file.

https://logserver.rdoproject.org/23/37423/9/check/periodic-tripleo-ci-centos-8-ovb-3ctlr_1comp_1supp-featureset039-train/71efe0d/logs/overcloud-controller-1/var/log/containers/nova/nova-conductor.log.txt.gz