fix: proxies set keep-alive timeouts to be system dependent (#10199)

Split the DialContext's one for internode and another
for all other external communications especially
proxy forwarders, gateway transport etc.

cmd/utils.go

@@ -1,5 +1,5 @@
 /*
- * MinIO Cloud Storage, (C) 2015, 2016, 2017 MinIO, Inc.
+ * MinIO Cloud Storage, (C) 2015-2020 MinIO, Inc.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -170,7 +170,7 @@ const (
 	// (Acceptable values range from 1 to 10000 inclusive)
 	globalMaxPartID = 10000
 
-	// Default values used while communicating for internode communication.
+	// Default values used while communicating for gateway communication
 	defaultDialTimeout = 5 * time.Second
 )
 
@@ -449,6 +449,29 @@ func ToS3ETag(etag string) string {
 	return etag
 }
 
+func newInternodeHTTPTransport(tlsConfig *tls.Config, dialTimeout time.Duration) func() *http.Transport {
+	// For more details about various values used here refer
+	// https://golang.org/pkg/net/http/#Transport documentation
+	tr := &http.Transport{
+		Proxy:                 http.ProxyFromEnvironment,
+		DialContext:           xhttp.NewInternodeDialContext(dialTimeout),
+		MaxIdleConnsPerHost:   16,
+		MaxIdleConns:          16,
+		IdleConnTimeout:       1 * time.Minute,
+		ResponseHeaderTimeout: 3 * time.Minute, // Set conservative timeouts for MinIO internode.
+		TLSHandshakeTimeout:   10 * time.Second,
+		ExpectContinueTimeout: 10 * time.Second,
+		TLSClientConfig:       tlsConfig,
+		// Go net/http automatically unzip if content-type is
+		// gzip disable this feature, as we are always interested
+		// in raw stream.
+		DisableCompression: true,
+	}
+	return func() *http.Transport {
+		return tr
+	}
+}
+
 func newCustomHTTPTransport(tlsConfig *tls.Config, dialTimeout time.Duration) func() *http.Transport {
 	// For more details about various values used here refer
 	// https://golang.org/pkg/net/http/#Transport documentation