Make iso-url configurable through config command

cmd/minikube/cmd/config/config.go

@@ -92,6 +92,11 @@ var settings = []Setting{
 		name: "kubernetes-version",
 		set:  SetString,
 	},
+	{
+		name:        "iso-url",
+		set:         SetString,
+		validations: []setFn{IsValidURL},
+	},
 	{
 		name: config.WantUpdateNotification,
 		set:  SetBool,

cmd/minikube/cmd/config/validations.go

@@ -19,6 +19,7 @@ package config
 import (
 	"fmt"
 	"net"
+	"net/url"
 	"os"
 	"strconv"
 
@@ -50,6 +51,14 @@ func IsValidDiskSize(name string, disksize string) error {
 	return nil
 }
 
+func IsValidURL(name string, location string) error {
+	_, err := url.Parse(location)
+	if err != nil {
+		return fmt.Errorf("%s is not a valid URL", location)
+	}
+	return nil
+}
+
 func IsPositive(name string, val string) error {
 	i, err := strconv.Atoi(val)
 	if err != nil {

docs/minikube_config.md

@@ -17,6 +17,7 @@ Configurable fields:
  * show-libmachine-logs
  * log_dir
  * kubernetes-version
+ * iso-url
  * WantUpdateNotification
  * ReminderWaitPeriodInHours
  * WantReportError