Add more debug logs

pkg/minikube/driver/driver.go

@@ -111,6 +111,7 @@ func Choose(options []registry.DriverState) (registry.DriverState, []registry.Dr
 			continue
 		}
 		if ds.Priority > pick.Priority {
+			glog.V(1).Infof("%q has a higher priority (%d) than %q (%d)", ds.Name, ds.Priority, pick.Name, pick.Priority)
 			pick = ds
 		}
 	}

pkg/minikube/registry/global.go

@@ -17,6 +17,8 @@ limitations under the License.
 package registry
 
 import (
+	"os"
+
 	"github.com/golang/glog"
 )
 
@@ -54,12 +56,16 @@ func Driver(name string) DriverDef {
 // Installed returns a list of installed drivers in the global registry
 func Installed() []DriverState {
 	sts := []DriverState{}
+	glog.Infof("Querying for installed drivers using PATH=%s", os.Getenv("PATH"))
+
 	for _, d := range globalRegistry.List() {
 		if d.Status == nil {
 			glog.Errorf("%q does not implement Status", d.Name)
 			continue
 		}
 		s := d.Status()
+		glog.Infof("%s priority: %d, state: %+v", d.Name, d.Priority, s)
+
 		if !s.Installed {
 			glog.Infof("%q not installed: %v", d.Name, s.Error)
 			continue

test/integration/a_serial_test.go

@@ -55,7 +55,14 @@ func TestDownloadOnly(t *testing.T) {
 				// Explicitly does not pass StartArgs() to test driver default
 				// --force to avoid uid check
 				args := []string{"start", "--download-only", "-p", profile, "--force", "--alsologtostderr", fmt.Sprintf("--kubernetes-version=%s", v)}
-				rrr, err = Run(t, exec.CommandContext(ctx, Target(), args...))
+
+				// Preserve the initial run-result for debugging
+				if rrr == nil {
+					rrr, err = Run(t, exec.CommandContext(ctx, Target(), args...))
+				} else {
+					_, err = Run(t, exec.CommandContext(ctx, Target(), args...))
+				}
+
 				if err != nil {
 					t.Errorf("%s failed: %v", args, err)
 				}