Ubuntu: error for minikube cache add images

[fenglixa]

The exact command to reproduce the issue:
$ minikube cache add ubuntu:16.04

The full output of the command that failed:
$ minikube cache add ubuntu:16.04

💣 Failed to cache and load images: Error creating new ssh host from driver: Error getting ssh host name for driver: driver does not support ssh commands

😿 Sorry that minikube crashed. If this was unexpected, we would love to hear from you:
👉 https://github.com/kubernetes/minikube/issues/new

The output of the minikube logs command:
None
The operating system version:
DISTRIB_ID=Ubuntu
DISTRIB_RELEASE=18.04

[fenglixa]

Checked the code. Why the logic of return error directly if the driver is none?

• none.go:

// GetSSHHostname returns hostname for use with ssh
func (d *Driver) GetSSHHostname() (string, error) {
	return "", fmt.Errorf("driver does not support ssh commands")   =====>>> Here
}

// GetSSHPort returns port for use with ssh
func (d *Driver) GetSSHPort() (int, error) {
	return 0, fmt.Errorf("driver does not support ssh commands")
}

[fenglixa]

Modified minikube code locally and setup password-less to localhost. I workarounded this issue:

$ ssh-copy-id -i ~/.ssh/id_rsa.pub 127.0.0.1
... ...
$ /opt/minikube# out/minikube cache add ubuntu:16.04
$ /opt/minikube# out/minikube cache list
ubuntu:16.04

[afbjorklund]

This can be fixed by switching runner for the none driver, run the load command locally instead of over ssh. It can also skip the copy step.

[afbjorklund]

Also note that caching is now disabled by default for the none driver, since the container runtime storage is persistent anyway.