ci: do not install Docker on the minikube host

Installing Docker CE on CentOS-8 currently conflicts with Podman. Both
tools can not be installed at the same time.

Instead of using the Docker command to push the image to to minikube VM,
read the image from stdin over ssh and load it with the Docker command
that is available inside the VM.

Signed-off-by: Niels de Vos <ndevos@redhat.com>

single-node-k8s.sh

@@ -75,14 +75,6 @@ function set_env() {
     export PATH=$PATH:/usr/local/bin
 }
 
-# FIXME: unfortunately minikube does not work with podman (yet)
-function install_docker()
-{
-    curl https://download.docker.com/linux/centos/docker-ce.repo -o /etc/yum.repos.d/docker-ce.repo
-    dnf -y --nobest install docker-ce
-    systemctl enable --now docker
-}
-
 function install_minikube()
 {
     dnf -y groupinstall 'Virtualization Host'
@@ -130,7 +122,12 @@ function deploy_rook()
 # When an image was built with podman, it needs importing into minikube.
 function podman2minikube()
 {
-    podman image save "${1}" | (eval "$(minikube docker-env --shell bash)" && docker image load)
+    # "minikube ssh" fails to read the image, so use standard ssh instead
+    podman image save "${1}" | \
+        ssh \
+            -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no \
+            -l docker -i "$(minikube ssh-key)" \
+            "$(minikube ip)" docker image load
 }
 
 # Set environment variables
@@ -139,7 +136,6 @@ set_env
 # prepare minikube environment
 install_minikube
 
-install_docker
 podman2minikube "quay.io/cephcsi/cephcsi:${CSI_IMAGE_VERSION}"
 
 deploy_rook