[hyperv] if no vswitch is specified, only pick the first external one

Dowideit, Sven (O&A, St. Lucia) · Dowideit, Sven (O&A, St. Lucia) · commit 30acfcbedcda · 2018-01-30T16:11:39.000+10:00
Signed-off-by: Dowideit, Sven (O&amp;A, St. Lucia) &lt;Sven.Dowideit@csiro.au&gt;
diff --git a/drivers/hyperv/hyperv.go b/drivers/hyperv/hyperv.go
@@ -255,21 +255,29 @@ func (d *Driver) Create() error {
 }
 
 func (d *Driver) chooseVirtualSwitch() (string, error) {
-	stdout, err := cmdOut("(Get-VMSwitch).Name")
-	if err != nil {
-		return "", err
-	}
+	if d.VSwitch == "" {
+		// Default to the first external switche and in the process avoid DockerNAT
+		stdout, err := cmdOut("(Get-VMSwitch -SwitchType External).Name")
+		if err != nil {
+			return "", err
+		}
 
-	switches := parseLines(stdout)
+		switches := parseLines(stdout)
 
-	if d.VSwitch == "" {
 		if len(switches) < 1 {
-			return "", fmt.Errorf("no vswitch found. A valid vswitch must be available for this command to run. Check https://docs.docker.com/machine/drivers/hyper-v/")
+			return "", fmt.Errorf("no External vswitch found. A valid vswitch must be available for this command to run. Check https://docs.docker.com/machine/drivers/hyper-v/")
 		}
 
 		return switches[0], nil
 	}
 
+	stdout, err := cmdOut("(Get-VMSwitch).Name")
+	if err != nil {
+		return "", err
+	}
+
+	switches := parseLines(stdout)
+
 	found := false
 	for _, name := range switches {
 		if name == d.VSwitch {
