Add metric for internode RPC calls errors (#11669)

cmd/rest/client.go

@@ -42,6 +42,19 @@ const (
 	closed
 )
 
+// Hold the number of failed RPC calls due to networking errors
+var networkErrsCounter uint64
+
+// GetNetworkErrsCounter returns the number of failed RPC requests
+func GetNetworkErrsCounter() uint64 {
+	return atomic.LoadUint64(&networkErrsCounter)
+}
+
+// ResetNetworkErrsCounter resets the number of failed RPC requests
+func ResetNetworkErrsCounter() {
+	atomic.StoreUint64(&networkErrsCounter, 0)
+}
+
 // NetworkError - error type in case of errors related to http/transport
 // for ex. connection refused, connection reset, dns resolution failure etc.
 // All errors returned by storage-rest-server (ex errFileNotFound, errDiskNotFound) are not considered to be network errors.
@@ -120,6 +133,7 @@ func (c *Client) Call(ctx context.Context, method string, values url.Values, bod
 	resp, err := c.httpClient.Do(req)
 	if err != nil {
 		if c.HealthCheckFn != nil && xnet.IsNetworkOrHostDown(err, c.ExpectTimeouts) {
+			atomic.AddUint64(&networkErrsCounter, 1)
 			if c.MarkOffline() {
 				logger.LogIf(ctx, fmt.Errorf("Marking %s temporary offline; caused by %w", c.url.String(), err))
 			}