Today I learned that there is a significant difference between the openshift-installer binary that is provided by Red Hat for their OCP version of OpenShift and the openshift-installer from OKD, that provides the free software version of OpenShift. The most noticeable difference is, that the OCP version of openshift-installer is not functional with Fedora CoreOS and will fail to bootstrap the cluster with wonderful error messages like kubelet.service: Failed to locate executable /usr/bin/hyperkube: No such file or directory and sed: can't read /etc/crio/crio.conf: No such file or directory. While there exist various issues to these topics on GitHub, no one bothered to point out, that the origin of this issue could be that one uses the wrong version of openshift-installer.

I came across this, while trying to setup an OKD cluster on Hetzner using the lovely hcloud-okd4 project and given my laziness I used the pre-build images from quay.io which only differ by version. And therefore I used 4.7.16 there instead of 4.7.0-0.okd-2021-06-19-191547, a mistake as I figured out now. If I would have used the make as described in the README, this would have been a non-issue.