netutil: add url comparison without resolver to URLStringsEqual

If one of the nodes in the cluster has lost a dns record,
restarting the second node will break it.
This PR makes an attempt to add a comparison without using a resolver,
which allows to protect cluster from dns errors and does not break
the current logic of comparing urls in the URLStringsEqual function.
You can read more in the issue #7798

Fixes #7798

Signed-off-by: Prasad Chandrasekaran <prasadc@vmware.com>

pkg/netutil/netutil.go

@@ -174,21 +174,13 @@ func URLStringsEqual(ctx context.Context, lg *zap.Logger, a []string, b []string
 	if len(a) != len(b) {
 		return false, fmt.Errorf("len(%q) != len(%q)", a, b)
 	}
-	urlsA := make([]url.URL, 0)
-	for _, str := range a {
-		u, err := url.Parse(str)
-		if err != nil {
-			return false, fmt.Errorf("failed to parse %q", str)
-		}
-		urlsA = append(urlsA, *u)
+	urlsA, err := stringsToURLs(a)
+	if err != nil {
+		return false, err
 	}
-	urlsB := make([]url.URL, 0)
-	for _, str := range b {
-		u, err := url.Parse(str)
-		if err != nil {
-			return false, fmt.Errorf("failed to parse %q", str)
-		}
-		urlsB = append(urlsB, *u)
+	urlsB, err := stringsToURLs(b)
+	if err != nil {
+		return false, err
 	}
 	return urlsEqual(ctx, lg, urlsA, urlsB)
 }
@@ -201,6 +193,18 @@ func urlsToStrings(us []url.URL) []string {
 	return rs
 }
 
+func stringsToURLs(us []string) ([]url.URL, error) {
+	urls := make([]url.URL, 0, len(us))
+	for _, str := range us {
+		u, err := url.Parse(str)
+		if err != nil {
+			return nil, fmt.Errorf("failed to parse %q", str)
+		}
+		urls = append(urls, *u)
+	}
+	return urls, nil
+}
+
 func IsNetworkTimeoutError(err error) bool {
 	nerr, ok := err.(net.Error)
 	return ok && nerr.Timeout()