Now that 4.8 has resolved router outages due to LocalTrafficPolicy, we can tighten the testing so that we don't regress. Add the same logic that control plane has to make upgrade non-disruptive for ingress.
checked upgrade ci and "disruption_tests: [sig-network-edge] Cluster frontend ingress remain available" is passed. see: https://prow.ci.openshift.org/view/gs/origin-ci-test/logs/periodic-ci-openshift-release-master-ci-4.9-e2e-aws-upgrade/1414662256355971072
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 (Moderate: OpenShift Container Platform 4.9.0 bug fix and security 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/RHSA-2021:3759