In [1], both 'Application behind service load balancer with PDB is not disrupted' and 'Image registry remain available' had outages of ~100ms. Perhaps that remaining disruption is an ingress/service thing, and no longer a registry thing? [1]: https://prow.ci.openshift.org/view/gs/origin-ci-test/logs/periodic-ci-openshift-release-master-ci-4.8-e2e-azure-upgrade/1452554396645724160
This fix should be in the version that you are upgrading from. To avoid disruptions the pods that are being deleted (old pods) should stay alive for some time until all components become aware that the pod will disappear. 4.8.0-0.ci-2021-10-21-200323 doesn't have the fix. Newer runs seems to be green.
Yes, it passed in new job:https://prow.ci.openshift.org/view/gs/origin-ci-test/logs/periodic-ci-openshift-release-master-ci-4.8-e2e-azure-upgrade/1453279562237480960 and testgrid can see it: https://testgrid.k8s.io/redhat-openshift-ocp-release-4.8-informing#periodic-ci-openshift-release-master-ci-4.8-e2e-azure-upgrade&include-filter-by-regex=remain%20available
Since the problem described in this bug report should be resolved in a recent advisory, it has been closed with a resolution of ERRATA. For information on the advisory (OpenShift Container Platform 4.8.18 bug fix update), and where to find the updated files, follow the link below. If the solution does not work for you, open a new bug report. https://access.redhat.com/errata/RHBA-2021:4020