Description of problem: Because RHCOS 46 dropped dhclient binary, localhost entry is no longer prepended to /etc/resolv.conf in coredns container. As a result, installation bails in bootstrap stage because api-int cannot be resolved. Here is the specific error message from bootstrap's journalctl: Jul 15 10:23:00 <fqdn> bootkube.sh[2272]: E0715 10:23:00.361298 1 reflector.go:178] k8s.io/client-go.3/tools/cache/reflector.go:125: Failed to list *v1.Etcd: Get "https://api-int.<domain>:6443/apis/operator.openshift.io/v1/etcds?fieldSelector=metadata.name%3Dcluster&limit=500&resourceVersion=0": dial tcp: lookup api-int.<domain> on <dns_server_ip>:53: no such host More details in this thread: https://coreos.slack.com/archives/CNSJG0ZED/p1594736797433300 Version-Release number of the following components: openshift-install-linux-4.6.0-0.nightly-2020-07-15-004428 RHCOS 46.82.202007051540-0 How reproducible: 100 % Steps to Reproduce: 1. openshift-install create cluster 2. Wait for bootstrap machine to be up 3. journalctl -b -f -u release-image.service -u bootkube.service on bootstrap machine Actaul results: Installation fails
The reason for this is that RHCOS 4.6 doesn't contain the dhclient binary, which means /etc/resolv.conf is missing the first nameserver 127.0.0.1 which should point at coredns . In other words /etc/dhcp/dhclient.conf is simply ignored The solution is to switch to using NetworkManager script to prepend that nameserver in /etc/resolv.conf (only for bootstrap - nodes already use that)
Verified with: openshift-install-linux-4.6.0-0.ci-2020-07-16-011059 Verification steps: 1. Run OCP4.6 installation 2. Make sure it finishes successfully 3. During bootstrap: 3.1 ssh core@<bastion_vm> 3.2 crictl ps 3.3 crictl exec -it <corends_container_id> 3.4 cat /etc/resolv.conf First nameserver must be 127.0.0.1
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 4.6 GA Images), 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-2020:4196