diff --git a/app/vminsert/graphite/server.go b/app/vminsert/graphite/server.go
index 401d516d2..621e3c6e0 100644
--- a/app/vminsert/graphite/server.go
+++ b/app/vminsert/graphite/server.go
@@ -21,36 +21,62 @@ var (
 	writeErrorsUDP   = metrics.NewCounter(`vm_graphite_request_errors_total{name="write", net="udp"}`)
 )
 
-// Serve starts graphite server on the given addr.
-func Serve(addr string) {
+// Server accepts Graphite plaintext lines over TCP and UDP.
+type Server struct {
+	addr  string
+	lnTCP net.Listener
+	lnUDP net.PacketConn
+	wg    sync.WaitGroup
+}
+
+// MustStart starts graphite server on the given addr.
+//
+// MustStop must be called on the returned server when it is no longer needed.
+func MustStart(addr string) *Server {
 	logger.Infof("starting TCP Graphite server at %q", addr)
 	lnTCP, err := netutil.NewTCPListener("graphite", addr)
 	if err != nil {
 		logger.Fatalf("cannot start TCP Graphite server at %q: %s", addr, err)
 	}
-	listenerTCP = lnTCP
 
 	logger.Infof("starting UDP Graphite server at %q", addr)
 	lnUDP, err := net.ListenPacket("udp4", addr)
 	if err != nil {
 		logger.Fatalf("cannot start UDP Graphite server at %q: %s", addr, err)
 	}
-	listenerUDP = lnUDP
 
-	var wg sync.WaitGroup
-	wg.Add(1)
+	s := &Server{
+		addr:  addr,
+		lnTCP: lnTCP,
+		lnUDP: lnUDP,
+	}
+	s.wg.Add(1)
 	go func() {
-		defer wg.Done()
-		serveTCP(listenerTCP)
+		defer s.wg.Done()
+		serveTCP(lnTCP)
 		logger.Infof("stopped TCP Graphite server at %q", addr)
 	}()
-	wg.Add(1)
+	s.wg.Add(1)
 	go func() {
-		defer wg.Done()
-		serveUDP(listenerUDP)
+		defer s.wg.Done()
+		serveUDP(lnUDP)
 		logger.Infof("stopped UDP Graphite server at %q", addr)
 	}()
-	wg.Wait()
+	return s
+}
+
+// MustStop stops the server.
+func (s *Server) MustStop() {
+	logger.Infof("stopping TCP Graphite server at %q...", s.addr)
+	if err := s.lnTCP.Close(); err != nil {
+		logger.Errorf("cannot close TCP Graphite server: %s", err)
+	}
+	logger.Infof("stopping UDP Graphite server at %q...", s.addr)
+	if err := s.lnUDP.Close(); err != nil {
+		logger.Errorf("cannot close UDP Graphite server: %s", err)
+	}
+	s.wg.Wait()
+	logger.Infof("TCP and UDP Graphite servers at %q have been stopped", s.addr)
 }
 
 func serveTCP(ln net.Listener) {
@@ -59,6 +85,7 @@ func serveTCP(ln net.Listener) {
 		if err != nil {
 			if ne, ok := err.(net.Error); ok {
 				if ne.Temporary() {
+					logger.Errorf("graphite: temporary error when listening for TCP addr %q: %s", ln.Addr(), err)
 					time.Sleep(time.Second)
 					continue
 				}
@@ -97,6 +124,7 @@ func serveUDP(ln net.PacketConn) {
 					writeErrorsUDP.Inc()
 					if ne, ok := err.(net.Error); ok {
 						if ne.Temporary() {
+							logger.Errorf("graphite: temporary error when listening for UDP addr %q: %s", ln.LocalAddr(), err)
 							time.Sleep(time.Second)
 							continue
 						}
@@ -119,20 +147,3 @@ func serveUDP(ln net.PacketConn) {
 	}
 	wg.Wait()
 }
-
-var (
-	listenerTCP net.Listener
-	listenerUDP net.PacketConn
-)
-
-// Stop stops the server.
-func Stop() {
-	logger.Infof("stopping TCP Graphite server at %q...", listenerTCP.Addr())
-	if err := listenerTCP.Close(); err != nil {
-		logger.Errorf("cannot close TCP Graphite server: %s", err)
-	}
-	logger.Infof("stopping UDP Graphite server at %q...", listenerUDP.LocalAddr())
-	if err := listenerUDP.Close(); err != nil {
-		logger.Errorf("cannot close UDP Graphite server: %s", err)
-	}
-}
diff --git a/app/vminsert/main.go b/app/vminsert/main.go
index e16813df4..a724f7a0a 100644
--- a/app/vminsert/main.go
+++ b/app/vminsert/main.go
@@ -19,39 +19,47 @@ import (
 )
 
 var (
-	graphiteListenAddr     = flag.String("graphiteListenAddr", "", "TCP and UDP address to listen for Graphite plaintext data. Usually :2003 must be set. Doesn't work if empty")
-	opentsdbListenAddr     = flag.String("opentsdbListenAddr", "", "TCP and UDP address to listen for OpentTSDB put messages. Usually :4242 must be set. Doesn't work if empty")
+	graphiteListenAddr = flag.String("graphiteListenAddr", "", "TCP and UDP address to listen for Graphite plaintext data. Usually :2003 must be set. Doesn't work if empty")
+	opentsdbListenAddr = flag.String("opentsdbListenAddr", "", "TCP and UDP address to listen for OpentTSDB metrics. "+
+		"Telnet put messages and HTTP /api/put messages are simultaneously served on TCP port. "+
+		"Usually :4242 must be set. Doesn't work if empty")
 	opentsdbHTTPListenAddr = flag.String("opentsdbHTTPListenAddr", "", "TCP address to listen for OpentTSDB HTTP put requests. Usually :4242 must be set. Doesn't work if empty")
 	maxInsertRequestSize   = flag.Int("maxInsertRequestSize", 32*1024*1024, "The maximum size of a single insert request in bytes")
 	maxLabelsPerTimeseries = flag.Int("maxLabelsPerTimeseries", 30, "The maximum number of labels accepted per time series. Superflouos labels are dropped")
 )
 
+var (
+	graphiteServer     *graphite.Server
+	opentsdbServer     *opentsdb.Server
+	opentsdbhttpServer *opentsdbhttp.Server
+)
+
 // Init initializes vminsert.
 func Init() {
 	storage.SetMaxLabelsPerTimeseries(*maxLabelsPerTimeseries)
 
 	concurrencylimiter.Init()
 	if len(*graphiteListenAddr) > 0 {
-		go graphite.Serve(*graphiteListenAddr)
+		graphiteServer = graphite.MustStart(*graphiteListenAddr)
 	}
 	if len(*opentsdbListenAddr) > 0 {
-		go opentsdb.Serve(*opentsdbListenAddr)
+		opentsdbServer = opentsdb.MustStart(*opentsdbListenAddr, int64(*maxInsertRequestSize))
 	}
 	if len(*opentsdbHTTPListenAddr) > 0 {
-		go opentsdbhttp.Serve(*opentsdbHTTPListenAddr, int64(*maxInsertRequestSize))
+		opentsdbhttpServer = opentsdbhttp.MustStart(*opentsdbHTTPListenAddr, int64(*maxInsertRequestSize))
 	}
 }
 
 // Stop stops vminsert.
 func Stop() {
 	if len(*graphiteListenAddr) > 0 {
-		graphite.Stop()
+		graphiteServer.MustStop()
 	}
 	if len(*opentsdbListenAddr) > 0 {
-		opentsdb.Stop()
+		opentsdbServer.MustStop()
 	}
 	if len(*opentsdbHTTPListenAddr) > 0 {
-		opentsdbhttp.Stop()
+		opentsdbhttpServer.MustStop()
 	}
 }
 
diff --git a/app/vminsert/opentsdb/listener_switch.go b/app/vminsert/opentsdb/listener_switch.go
new file mode 100644
index 000000000..bd4689587
--- /dev/null
+++ b/app/vminsert/opentsdb/listener_switch.go
@@ -0,0 +1,159 @@
+package opentsdb
+
+import (
+	"io"
+	"net"
+	"sync"
+	"time"
+
+	"github.com/VictoriaMetrics/VictoriaMetrics/lib/logger"
+)
+
+// listenerSwitch listens for incoming connections and multiplexes them to OpenTSDB http or telnet listeners
+// depending on the first byte in the accepted connection.
+//
+// It is expected that both listeners - http and telnet consume incoming connections as soon as possible.
+type listenerSwitch struct {
+	ln net.Listener
+	wg sync.WaitGroup
+
+	telnetConnsCh chan net.Conn
+	httpConnsCh   chan net.Conn
+
+	closeLock sync.Mutex
+	closed    bool
+	acceptErr error
+	closeErr  error
+}
+
+func newListenerSwitch(ln net.Listener) *listenerSwitch {
+	ls := &listenerSwitch{
+		ln: ln,
+	}
+	ls.telnetConnsCh = make(chan net.Conn)
+	ls.httpConnsCh = make(chan net.Conn)
+	ls.wg.Add(1)
+	go func() {
+		ls.worker()
+		close(ls.telnetConnsCh)
+		close(ls.httpConnsCh)
+		ls.wg.Done()
+	}()
+	return ls
+}
+
+func (ls *listenerSwitch) stop() error {
+	var err error
+	ls.closeLock.Lock()
+	if !ls.closed {
+		err = ls.ln.Close()
+		ls.closeErr = err
+		ls.closed = true
+	}
+	ls.closeLock.Unlock()
+
+	if err == nil {
+		// Wait until worker detects the closed ls.ln and exits.
+		ls.wg.Wait()
+	}
+	return err
+}
+
+func (ls *listenerSwitch) worker() {
+	var buf [1]byte
+	for {
+		c, err := ls.ln.Accept()
+		if err != nil {
+			if ne, ok := err.(net.Error); ok && ne.Temporary() {
+				logger.Infof("listenerSwitch: temporary error at %q: %s; sleeping for a second...", ls.ln.Addr(), err)
+				time.Sleep(time.Second)
+				continue
+			}
+			ls.closeLock.Lock()
+			ls.acceptErr = err
+			ls.closeLock.Unlock()
+			return
+		}
+		if _, err := io.ReadFull(c, buf[:]); err != nil {
+			logger.Errorf("listenerSwitch: cannot read one byte from the underlying connection for %q: %s", ls.ln.Addr(), err)
+			_ = c.Close()
+			continue
+		}
+
+		// It is expected that both listeners - http and telnet consume incoming connections as soon as possible,
+		// so the below code shouldn't block for extended periods of time.
+		pc := &peekedConn{
+			Conn:      c,
+			firstChar: buf[0],
+		}
+		if buf[0] == 'p' {
+			// Assume the request starts with `put`.
+			ls.telnetConnsCh <- pc
+		} else {
+			// Assume the request starts with `POST`.
+			ls.httpConnsCh <- pc
+		}
+	}
+}
+
+type peekedConn struct {
+	net.Conn
+	firstChar     byte
+	firstCharRead bool
+}
+
+func (pc *peekedConn) Read(p []byte) (int, error) {
+	// It is assumed that the pc cannot be read from concurrent goroutines.
+	if pc.firstCharRead {
+		// Fast path - first char already read.
+		return pc.Conn.Read(p)
+	}
+
+	// Slow path - read the first char.
+	if len(p) == 0 {
+		return 0, nil
+	}
+	p[0] = pc.firstChar
+	pc.firstCharRead = true
+	n, err := pc.Conn.Read(p[1:])
+	return n + 1, err
+}
+
+func (ls *listenerSwitch) newTelnetListener() *chanListener {
+	return &chanListener{
+		ls: ls,
+		ch: ls.telnetConnsCh,
+	}
+}
+
+func (ls *listenerSwitch) newHTTPListener() *chanListener {
+	return &chanListener{
+		ls: ls,
+		ch: ls.httpConnsCh,
+	}
+}
+
+type chanListener struct {
+	ls *listenerSwitch
+	ch chan net.Conn
+}
+
+func (cl *chanListener) Accept() (net.Conn, error) {
+	c, ok := <-cl.ch
+	if ok {
+		return c, nil
+	}
+
+	cl.ls.closeLock.Lock()
+	err := cl.ls.acceptErr
+	cl.ls.closeLock.Unlock()
+	return nil, err
+}
+
+func (cl *chanListener) Close() error {
+	return cl.ls.stop()
+}
+
+func (cl *chanListener) Addr() net.Addr {
+	return cl.ls.ln.Addr()
+}
diff --git a/app/vminsert/opentsdb/server.go b/app/vminsert/opentsdb/server.go
index 229e09a35..ce6d14367 100644
--- a/app/vminsert/opentsdb/server.go
+++ b/app/vminsert/opentsdb/server.go
@@ -7,6 +7,7 @@ import (
 	"sync"
 	"time"
 
+	"github.com/VictoriaMetrics/VictoriaMetrics/app/vminsert/opentsdbhttp"
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/bytesutil"
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/logger"
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/netutil"
@@ -21,44 +22,91 @@ var (
 	writeErrorsUDP   = metrics.NewCounter(`vm_opentsdb_request_errors_total{name="write", net="udp"}`)
 )
 
-// Serve starts OpenTSDB collector on the given addr.
-func Serve(addr string) {
+// Server is a server for collecting OpenTSDB TCP and UDP metrics.
+//
+// It accepts simultaneously Telnet put requests and HTTP put requests over TCP.
+type Server struct {
+	addr       string
+	ls         *listenerSwitch
+	httpServer *opentsdbhttp.Server
+	lnUDP      net.PacketConn
+	wg         sync.WaitGroup
+}
+
+// MustStart starts OpenTSDB collector on the given addr.
+//
+// MustStop must be called on the returned server when it is no longer needed.
+func MustStart(addr string, maxRequestSize int64) *Server {
 	logger.Infof("starting TCP OpenTSDB collector at %q", addr)
 	lnTCP, err := netutil.NewTCPListener("opentsdb", addr)
 	if err != nil {
 		logger.Fatalf("cannot start TCP OpenTSDB collector at %q: %s", addr, err)
 	}
-	listenerTCP = lnTCP
+	ls := newListenerSwitch(lnTCP)
+	lnHTTP := ls.newHTTPListener()
+	lnTelnet := ls.newTelnetListener()
+	httpServer := opentsdbhttp.MustServe(lnHTTP, maxRequestSize)
 
 	logger.Infof("starting UDP OpenTSDB collector at %q", addr)
 	lnUDP, err := net.ListenPacket("udp4", addr)
 	if err != nil {
 		logger.Fatalf("cannot start UDP OpenTSDB collector at %q: %s", addr, err)
 	}
-	listenerUDP = lnUDP
 
-	var wg sync.WaitGroup
-	wg.Add(1)
+	s := &Server{
+		addr:       addr,
+		ls:         ls,
+		httpServer: httpServer,
+		lnUDP:      lnUDP,
+	}
+	s.wg.Add(1)
 	go func() {
-		defer wg.Done()
-		serveTCP(listenerTCP)
-		logger.Infof("stopped TCP OpenTSDB collector at %q", addr)
+		defer s.wg.Done()
+		serveTelnet(lnTelnet)
+		logger.Infof("stopped TCP telnet OpenTSDB server at %q", addr)
 	}()
-	wg.Add(1)
+	s.wg.Add(1)
 	go func() {
-		defer wg.Done()
-		serveUDP(listenerUDP)
-		logger.Infof("stopped UDP OpenTSDB collector at %q", addr)
+		defer s.wg.Done()
+		httpServer.Wait()
+		// Do not log when httpServer is stopped, since this is logged by the server itself.
 	}()
-	wg.Wait()
+	s.wg.Add(1)
+	go func() {
+		defer s.wg.Done()
+		serveUDP(lnUDP)
+		logger.Infof("stopped UDP OpenTSDB server at %q", addr)
+	}()
+	return s
 }
 
-func serveTCP(ln net.Listener) {
+// MustStop stops the server.
+func (s *Server) MustStop() {
+	// Stop HTTP server. Do not emit log message, since it is emitted by the httpServer.
+	s.httpServer.MustStop()
+
+	logger.Infof("stopping TCP telnet OpenTSDB server at %q...", s.addr)
+	if err := s.ls.stop(); err != nil {
+		logger.Errorf("cannot stop TCP telnet OpenTSDB server: %s", err)
+	}
+
+	logger.Infof("stopping UDP OpenTSDB server at %q...", s.addr)
+	if err := s.lnUDP.Close(); err != nil {
+		logger.Errorf("cannot stop UDP OpenTSDB server: %s", err)
+	}
+
+	// Wait until all the servers are stopped.
+	s.wg.Wait()
+	logger.Infof("TCP and UDP OpenTSDB servers at %q have been stopped", s.addr)
+}
+
+func serveTelnet(ln net.Listener) {
 	for {
 		c, err := ln.Accept()
 		if err != nil {
 			if ne, ok := err.(net.Error); ok {
 				if ne.Temporary() {
+					logger.Errorf("opentsdb: temporary error when listening for TCP addr %q: %s", ln.Addr(), err)
 					time.Sleep(time.Second)
 					continue
 				}
@@ -97,6 +145,7 @@ func serveUDP(ln net.PacketConn) {
 					writeErrorsUDP.Inc()
 					if ne, ok := err.(net.Error); ok {
 						if ne.Temporary() {
+							logger.Errorf("opentsdb: temporary error when listening for UDP addr %q: %s", ln.LocalAddr(), err)
 							time.Sleep(time.Second)
 							continue
 						}
@@ -119,20 +168,3 @@ func serveUDP(ln net.PacketConn) {
 	}
 	wg.Wait()
 }
-
-var (
-	listenerTCP net.Listener
-	listenerUDP net.PacketConn
-)
-
-// Stop stops the server.
-func Stop() {
-	logger.Infof("stopping TCP OpenTSDB server at %q...", listenerTCP.Addr())
-	if err := listenerTCP.Close(); err != nil {
-		logger.Errorf("cannot close TCP OpenTSDB server: %s", err)
-	}
-	logger.Infof("stopping UDP OpenTSDB server at %q...", listenerUDP.LocalAddr())
-	if err := listenerUDP.Close(); err != nil {
-		logger.Errorf("cannot close UDP OpenTSDB server: %s", err)
-	}
-}
diff --git a/app/vminsert/opentsdbhttp/server.go b/app/vminsert/opentsdbhttp/server.go
index 6652d21fe..cb882838a 100644
--- a/app/vminsert/opentsdbhttp/server.go
+++ b/app/vminsert/opentsdbhttp/server.go
@@ -2,11 +2,14 @@ package opentsdbhttp
 
 import (
 	"context"
+	"net"
 	"net/http"
+	"sync"
 	"time"
 
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/httpserver"
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/logger"
+	"github.com/VictoriaMetrics/VictoriaMetrics/lib/netutil"
 	"github.com/VictoriaMetrics/metrics"
 )
 
@@ -15,56 +18,84 @@ var (
 	writeErrors   = metrics.NewCounter(`vm_http_request_errors_total{path="/api/put", protocol="opentsdb-http"}`)
 )
 
-var (
-	httpServer     *http.Server
-	httpAddr       string
-	maxRequestSize int64
-)
+// Server represents HTTP OpenTSDB server.
+type Server struct {
+	s  *http.Server
+	ln net.Listener
+	wg sync.WaitGroup
+}
 
-// Serve starts HTTP OpenTSDB server on the given addr.
-func Serve(addr string, maxReqSize int64) {
+// MustStart starts HTTP OpenTSDB server on the given addr.
+//
+// MustStop must be called on the returned server when it is no longer needed.
+func MustStart(addr string, maxRequestSize int64) *Server {
 	logger.Infof("starting HTTP OpenTSDB server at %q", addr)
-	httpAddr = addr
-	maxRequestSize = maxReqSize
-	httpServer = &http.Server{
-		Addr:         addr,
-		Handler:      http.HandlerFunc(requestHandler),
+	lnTCP, err := netutil.NewTCPListener("opentsdbhttp", addr)
+	if err != nil {
+		logger.Fatalf("cannot start HTTP OpenTSDB collector at %q: %s", addr, err)
+	}
+	return MustServe(lnTCP, maxRequestSize)
+}
+
+// MustServe serves OpenTSDB HTTP put requests from ln with up to maxRequestSize size.
+//
+// MustStop must be called on the returned server when it is no longer needed.
+func MustServe(ln net.Listener, maxRequestSize int64) *Server {
+	h := newRequestHandler(maxRequestSize)
+	hs := &http.Server{
+		Handler:      h,
 		ReadTimeout:  30 * time.Second,
 		WriteTimeout: 10 * time.Second,
 	}
+	s := &Server{
+		s:  hs,
+		ln: ln,
+	}
+	s.wg.Add(1)
 	go func() {
-		err := httpServer.ListenAndServe()
+		defer s.wg.Done()
+		err := s.s.Serve(s.ln)
 		if err == http.ErrServerClosed {
 			return
 		}
 		if err != nil {
-			logger.Fatalf("error serving HTTP OpenTSDB: %s", err)
+			logger.Fatalf("error serving HTTP OpenTSDB at %q: %s", s.ln.Addr(), err)
 		}
 	}()
+	return s
 }
 
-// requestHandler handles HTTP OpenTSDB insert request.
-func requestHandler(w http.ResponseWriter, r *http.Request) {
-	switch r.URL.Path {
-	case "/api/put":
-		writeRequests.Inc()
-		if err := insertHandler(r, maxRequestSize); err != nil {
-			writeErrors.Inc()
-			httpserver.Errorf(w, "error in %q: %s", r.URL.Path, err)
-			return
-		}
-		w.WriteHeader(http.StatusNoContent)
-	default:
-		httpserver.Errorf(w, "unexpected path requested on HTTP OpenTSDB server: %q", r.URL.Path)
-	}
+// Wait waits until the server is stopped with MustStop.
+func (s *Server) Wait() {
+	s.wg.Wait()
 }
 
-// Stop stops HTTP OpenTSDB server.
-func Stop() {
-	logger.Infof("stopping HTTP OpenTSDB server at %q...", httpAddr)
+// MustStop stops HTTP OpenTSDB server.
+func (s *Server) MustStop() {
+	logger.Infof("stopping HTTP OpenTSDB server at %q...", s.ln.Addr())
 	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
 	defer cancel()
-	if err := httpServer.Shutdown(ctx); err != nil {
-		logger.Fatalf("cannot close HTTP OpenTSDB server: %s", err)
+	if err := s.s.Shutdown(ctx); err != nil {
+		logger.Fatalf("cannot close HTTP OpenTSDB server at %q: %s", s.ln.Addr(), err)
 	}
+	s.wg.Wait()
+	logger.Infof("OpenTSDB HTTP server at %q has been stopped", s.ln.Addr())
+}
+
+func newRequestHandler(maxRequestSize int64) http.Handler {
+	rh := func(w http.ResponseWriter, r *http.Request) {
+		switch r.URL.Path {
+		case "/api/put":
+			writeRequests.Inc()
+			if err := insertHandler(r, maxRequestSize); err != nil {
+				writeErrors.Inc()
+				httpserver.Errorf(w, "error in %q: %s", r.URL.Path, err)
+				return
+			}
+			w.WriteHeader(http.StatusNoContent)
+		default:
+			httpserver.Errorf(w, "unexpected path requested on HTTP OpenTSDB server: %q", r.URL.Path)
+		}
+	}
+	return http.HandlerFunc(rh)
 }
diff --git a/lib/netutil/tcplistener.go b/lib/netutil/tcplistener.go
index 31d3ae40e..02f8dda9f 100644
--- a/lib/netutil/tcplistener.go
+++ b/lib/netutil/tcplistener.go
@@ -6,6 +6,7 @@ import (
 	"net"
 	"time"
 
+	"github.com/VictoriaMetrics/VictoriaMetrics/lib/logger"
 	"github.com/VictoriaMetrics/metrics"
 )
 
@@ -72,6 +73,8 @@ func (ln *TCPListener) Accept() (net.Conn, error) {
 		ln.accepts.Inc()
 		if err != nil {
 			if ne, ok := err.(net.Error); ok && ne.Temporary() {
+				logger.Errorf("temporary error when listening for TCP addr %q: %s", ln.Addr(), err)
+				time.Sleep(time.Second)
 				continue
 			}
 			ln.acceptErrors.Inc()