Description of problem: OCP explicitly does not allow the use of the following reserved address blocks. 2001:db8::/32 192.0.2.0/24 If the render command observes these in the install-config as machineCidr it should fail and provide a clear message to admin. https://github.com/openshift/cluster-kube-apiserver-operator/blob/d6a60b2c18806d69dcf27228aacb830a699126f3/pkg/operator/configobservation/etcdendpoints/observe_etcd_endpoints.go#L72 Version-Release number of selected component (if applicable): How reproducible: 100% Steps to Reproduce: 1. create a cluster with machineCidr defined using one of the ranges above 2. cluster will fail to bootstrap because we will skip these endpoints in the observers used by the control-plane operators[1]. 3. Actual results: bootstrap fails for an unknown reason. Expected results: bootstrap fails early as possible with a clear message indicating the address range is unsupported. Additional info: [1] https://github.com/openshift/cluster-kube-apiserver-operator/blob/d6a60b2c18806d69dcf27228aacb830a699126f3/pkg/operator/configobservation/etcdendpoints/observe_etcd_endpoints.go#L72
With no customer cases attached and fixes having made it no further than 4.9 I'm going ahead and closing this as it's unlikely that we're on track to close this before 4.6 EOL.