fix: limit HTTP transport tuables to affordable values (#9383)

Close connections pro-actively in transient calls

cmd/admin-handlers.go

@@ -986,7 +986,7 @@ func (a adminAPIHandlers) TraceHandler(w http.ResponseWriter, r *http.Request) {
 	// Use buffered channel to take care of burst sends or slow w.Write()
 	traceCh := make(chan interface{}, 4000)
 
-	peers := getRestClients(globalEndpoints)
+	peers := newPeerRestClients(globalEndpoints)
 
 	globalHTTPTrace.Subscribe(traceCh, ctx.Done(), func(entry interface{}) bool {
 		return mustTrace(entry, trcAll, trcErr)
@@ -1051,7 +1051,7 @@ func (a adminAPIHandlers) ConsoleLogHandler(w http.ResponseWriter, r *http.Reque
 
 	logCh := make(chan interface{}, 4000)
 
-	peers := getRestClients(globalEndpoints)
+	peers := newPeerRestClients(globalEndpoints)
 
 	globalConsoleSys.Subscribe(logCh, ctx.Done(), node, limitLines, logKind, nil)
 
@@ -1482,7 +1482,9 @@ func (a adminAPIHandlers) ServerInfoHandler(w http.ResponseWriter, r *http.Reque
 func fetchLambdaInfo(cfg config.Config) []map[string][]madmin.TargetIDStatus {
 
 	// Fetch the configured targets
-	targetList, err := notify.FetchRegisteredTargets(cfg, GlobalContext.Done(), NewGatewayHTTPTransport(), true, false)
+	tr := NewGatewayHTTPTransport()
+	defer tr.CloseIdleConnections()
+	targetList, err := notify.FetchRegisteredTargets(cfg, GlobalContext.Done(), tr, true, false)
 	if err != nil && err != notify.ErrTargetsOffline {
 		logger.LogIf(GlobalContext, err)
 		return nil
@@ -1605,12 +1607,8 @@ func checkConnection(endpointStr string, timeout time.Duration) error {
 		return pErr
 	}
 
-	tr := newCustomHTTPTransport(
-		&tls.Config{RootCAs: globalRootCAs},
-		timeout,
-		0, /* Default value */
-	)()
-
+	tr := newCustomHTTPTransport(&tls.Config{RootCAs: globalRootCAs}, timeout)()
+	defer tr.CloseIdleConnections()
 	if dErr := u.DialHTTP(tr); dErr != nil {
 		if urlErr, ok := dErr.(*url.Error); ok {
 			// To treat "connection refused" errors as un reachable endpoint.

cmd/bootstrap-peer-server.go

@@ -247,7 +247,7 @@ func newBootstrapRESTClient(endpoint Endpoint) (*bootstrapRESTClient, error) {
 		}
 	}
 
-	trFn := newCustomHTTPTransport(tlsConfig, rest.DefaultRESTTimeout, rest.DefaultRESTTimeout)
+	trFn := newCustomHTTPTransport(tlsConfig, rest.DefaultRESTTimeout)
 	restClient, err := rest.NewClient(serverURL, trFn, newAuthToken)
 	if err != nil {
 		return nil, err

cmd/bucket-notification-handlers.go

@@ -286,7 +286,7 @@ func (api objectAPIHandlers) ListenBucketNotificationHandler(w http.ResponseWrit
 	// Use buffered channel to take care of burst sends or slow w.Write()
 	listenCh := make(chan interface{}, 4000)
 
-	peers := getRestClients(globalEndpoints)
+	peers := newPeerRestClients(globalEndpoints)
 
 	globalHTTPListen.Subscribe(listenCh, ctx.Done(), func(evI interface{}) bool {
 		ev, ok := evI.(event.Event)

cmd/lock-rest-client.go

@@ -170,7 +170,7 @@ func newlockRESTClient(endpoint Endpoint) *lockRESTClient {
 		}
 	}
 
-	trFn := newCustomHTTPTransport(tlsConfig, rest.DefaultRESTTimeout, rest.DefaultRESTTimeout)
+	trFn := newCustomHTTPTransport(tlsConfig, rest.DefaultRESTTimeout)
 	restClient, err := rest.NewClient(serverURL, trFn, newAuthToken)
 	if err != nil {
 		logger.LogIf(GlobalContext, err)

cmd/notification.go

@@ -1171,7 +1171,7 @@ func NewNotificationSys(endpoints EndpointZones) *NotificationSys {
 		targetList:                 event.NewTargetList(),
 		bucketRulesMap:             make(map[string]event.RulesMap),
 		bucketRemoteTargetRulesMap: make(map[string]map[event.TargetID]event.RulesMap),
-		peerClients:                getRestClients(endpoints),
+		peerClients:                newPeerRestClients(endpoints),
 	}
 }
 

cmd/object-handlers.go

@@ -27,6 +27,7 @@ import (
 	"sort"
 	"strconv"
 	"strings"
+	"sync"
 
 	"time"
 
@@ -663,6 +664,10 @@ func getCpObjTagsFromHeader(ctx context.Context, r *http.Request, tags string) (
 	return tags, nil
 }
 
+// getRemoteInstanceTransport contains a singleton roundtripper.
+var getRemoteInstanceTransport http.RoundTripper
+var getRemoteInstanceTransportOnce sync.Once
+
 // Returns a minio-go Client configured to access remote host described by destDNSRecord
 // Applicable only in a federated deployment
 var getRemoteInstanceClient = func(r *http.Request, host string) (*miniogo.Core, error) {
@@ -673,7 +678,10 @@ var getRemoteInstanceClient = func(r *http.Request, host string) (*miniogo.Core,
 	if err != nil {
 		return nil, err
 	}
-	core.SetCustomTransport(NewGatewayHTTPTransport())
+	getRemoteInstanceTransportOnce.Do(func() {
+		getRemoteInstanceTransport = NewGatewayHTTPTransport()
+	})
+	core.SetCustomTransport(getRemoteInstanceTransport)
 	return core, nil
 }
 

cmd/peer-rest-client.go

@@ -1002,7 +1002,8 @@ func getRemoteHosts(endpointZones EndpointZones) []*xnet.Host {
 	return remoteHosts
 }
 
-func getRestClients(endpoints EndpointZones) []*peerRESTClient {
+// newPeerRestClients creates new peer clients.
+func newPeerRestClients(endpoints EndpointZones) []*peerRESTClient {
 	peerHosts := getRemoteHosts(endpoints)
 	restClients := make([]*peerRESTClient, len(peerHosts))
 	for i, host := range peerHosts {
@@ -1019,7 +1020,6 @@ func getRestClients(endpoints EndpointZones) []*peerRESTClient {
 
 // Returns a peer rest client.
 func newPeerRESTClient(peer *xnet.Host) (*peerRESTClient, error) {
-
 	scheme := "http"
 	if globalIsSSL {
 		scheme = "https"
@@ -1039,7 +1039,7 @@ func newPeerRESTClient(peer *xnet.Host) (*peerRESTClient, error) {
 		}
 	}
 
-	trFn := newCustomHTTPTransport(tlsConfig, rest.DefaultRESTTimeout, rest.DefaultRESTTimeout)
+	trFn := newCustomHTTPTransport(tlsConfig, rest.DefaultRESTTimeout)
 	restClient, err := rest.NewClient(serverURL, trFn, newAuthToken)
 	if err != nil {
 		return nil, err

cmd/prepare-storage.go

@@ -201,12 +201,12 @@ func IsServerResolvable(endpoint Endpoint) error {
 	}
 
 	httpClient := &http.Client{
-		Transport: newCustomHTTPTransport(tlsConfig, rest.DefaultRESTTimeout, rest.DefaultRESTTimeout)(),
+		Transport: newCustomHTTPTransport(tlsConfig, rest.DefaultRESTTimeout)(),
 	}
+	defer httpClient.CloseIdleConnections()
 
 	resp, err := httpClient.Do(req)
 	if err != nil {
-		httpClient.CloseIdleConnections()
 		return err
 	}
 	defer xhttp.DrainBody(resp.Body)

cmd/storage-rest-client.go

@@ -572,7 +572,7 @@ func newStorageRESTClient(endpoint Endpoint) *storageRESTClient {
 		}
 	}
 
-	trFn := newCustomHTTPTransport(tlsConfig, rest.DefaultRESTTimeout, rest.DefaultRESTTimeout)
+	trFn := newCustomHTTPTransport(tlsConfig, rest.DefaultRESTTimeout)
 	restClient, err := rest.NewClient(serverURL, trFn, newAuthToken)
 	if err != nil {
 		logger.LogIf(GlobalContext, err)

cmd/utils.go

@@ -173,7 +173,6 @@ const (
 
 	// Default values used while communicating for internode communication.
 	defaultDialTimeout = 5 * time.Second
-	defaultDialKeepAlive = 15 * time.Second
 )
 
 // isMaxObjectSize - verify if max object size
@@ -464,14 +463,16 @@ func newCustomDialContext(dialTimeout, dialKeepAlive time.Duration) dialContext
 	}
 }
 
-func newCustomHTTPTransport(tlsConfig *tls.Config, dialTimeout, dialKeepAlive time.Duration) func() *http.Transport {
+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
 	tr := &http.Transport{
 		Proxy:                 http.ProxyFromEnvironment,
-		DialContext:           newCustomDialContext(dialTimeout, dialKeepAlive),
-		MaxIdleConnsPerHost:   256,
-		IdleConnTimeout:       time.Minute,
+		DialContext:           newCustomDialContext(dialTimeout, 15*time.Second),
+		MaxIdleConnsPerHost:   16,
+		MaxIdleConns:          16,
+		MaxConnsPerHost:       64, // This is used per drive/rpc host. More requests will block until free.
+		IdleConnTimeout:       1 * time.Minute,
 		ResponseHeaderTimeout: 3 * time.Minute, // Set conservative timeouts for MinIO internode.
 		TLSHandshakeTimeout:   10 * time.Second,
 		ExpectContinueTimeout: 10 * time.Second,
@@ -493,9 +494,14 @@ func newCustomHTTPTransport(tlsConfig *tls.Config, dialTimeout, dialKeepAlive ti
 func NewGatewayHTTPTransport() *http.Transport {
 	tr := newCustomHTTPTransport(&tls.Config{
 		RootCAs: globalRootCAs,
-	}, defaultDialTimeout, defaultDialKeepAlive)()
+	}, defaultDialTimeout)()
 	// Set aggressive timeouts for gateway
 	tr.ResponseHeaderTimeout = 30 * time.Second
+
+	// Allow more requests to be in flight.
+	tr.MaxConnsPerHost = 256
+	tr.MaxIdleConnsPerHost = 16
+	tr.MaxIdleConns = 256
 	return tr
 }
 

cmd/web-handlers.go

@@ -2109,10 +2109,10 @@ func (web *webAPIHandlers) LoginSTS(r *http.Request, args *LoginSTSArgs, reply *
 	clnt := &http.Client{
 		Transport: NewGatewayHTTPTransport(),
 	}
+	defer clnt.CloseIdleConnections()
 
 	resp, err := clnt.Do(req)
 	if err != nil {
-		clnt.CloseIdleConnections()
 		return toJSONError(ctx, err)
 	}
 	defer xhttp.DrainBody(resp.Body)