ENV for matching CRI runtime

[vbatts]

Is this a BUG REPORT or FEATURE REQUEST? (choose one): BUG?

Environment:

Minikube version (use minikube version): v0.28.2

• OS (e.g. from /etc/os-release): fedora 28
• VM Driver (e.g. cat ~/.minikube/machines/minikube/config.json | grep DriverName): VirtualBox
• ISO version (e.g. cat ~/.minikube/machines/minikube/config.json | grep -i ISO or minikube ssh cat /etc/VERSION): v0.28.1.iso
• Install tools:
• Others:

What happened:
Started minikube with minikube start --vm-driver=virtualbox --container-runtime=crio
Then:

$> minikube ssh
$> sudo su -
#> crictl ps
FATA[0000] listing containers failed: rpc error: code = Unavailable desc = grpc: the connection is unavailable 

What you expected to happen:
See the running containers

the issue and resolution:
with no --runtime-endpoint flag or $CONTAINER_RUNTIME_ENDPOINT env variable, then crictl defaults to "unix:///var/run/dockershim.sock". BUT since we've specified crio then there ought to be a system env variable like CONTAINER_RUNTIME_ENDPOINT="unix:///var/run/crio/crio.sock".

In the meantime, using crictl -r unix:///var/run/crio/crio.sock ps works fine, but must be used on every command (or just export CONTAINER_RUNTIME_ENDPOINT="unix:///var/run/crio/crio.sock")

[prabhatsharma]

I had to run below to make it work
$sudo crictl -r unix:///var/run/containerd/containerd.sock ps

[tstromberg]

Dupe of #3043