kubernetes installation on RHEL8 Fatal:docker.service not found
Use CRI-O as the container runtime instead of Docker. OpenShift uses CRI-O on RHEL8 so it is well supported (here's why).
Quoting a statement from this doc.
The docker package is not shipped or supported by Red Hat for Red Hat Enterprise Linux (RHEL) 8. The docker container engine is replaced by a suite of tools in the Container Tools module.
You need to use CRI-O as container runtime instead of docker, this doc will help.
OR
Try this hack to install docker-ce on rhel-8.
You need to install docker manually using yum package manager. Then you should be able to initialize kubeadm