Only add docker group for the docker runtime

pkg/drivers/ssh/ssh.go

@@ -20,6 +20,7 @@ import (
 	"fmt"
 	"net"
 	"os"
+	"os/exec"
 	"path"
 	"strconv"
 	"time"
@@ -124,6 +125,12 @@ func (d *Driver) Create() error {
 		}
 	}
 
+	if d.runtime.Name() == "Docker" {
+		if _, err := d.exec.RunCmd(exec.Command("sudo", "usermod", "-aG", "docker", d.GetSSHUsername())); err != nil {
+			return errors.Wrap(err, "usermod")
+		}
+	}
+
 	log.Debugf("IP: %s", d.IPAddress)
 
 	return nil

pkg/minikube/machine/start.go

@@ -174,12 +174,6 @@ func createHost(api libmachine.API, cfg *config.ClusterConfig, n *config.Node) (
 		return h, errors.Wrap(err, "post-start")
 	}
 
-	if driver.IsSSH(h.Driver.DriverName()) {
-		if _, err := h.RunSSHCommand(fmt.Sprintf("sudo usermod -aG docker %s", h.Driver.GetSSHUsername())); err != nil {
-			return h, errors.Wrap(err, "usermod")
-		}
-	}
-
 	if err := saveHost(api, h, cfg, n); err != nil {
 		return h, err
 	}