Description
When the kafka.network.Acceptor in SocketServer.scala accepts a new connection in the `accept` function, it handles the `TooManyConnectionsException` and `ConnectionThrottledException`. However, the socketChannel operations (line 720 or 721 or 722) within the try block may potentially throw an IOException as well, which is not handled.
//core/src/main/scala/kafka/network/SocketServer.scala // Acceptor class private def accept(key: SelectionKey): Option[SocketChannel] = { val serverSocketChannel = key.channel().asInstanceOf[ServerSocketChannel] val socketChannel = serverSocketChannel.accept() // line 717 try { connectionQuotas.inc(endPoint.listenerName, socketChannel.socket.getInetAddress, blockedPercentMeter) socketChannel.configureBlocking(false) // line 720 socketChannel.socket().setTcpNoDelay(true) // line 721 socketChannel.socket().setKeepAlive(true) // line 722 if (sendBufferSize != Selectable.USE_DEFAULT_BUFFER_SIZE) socketChannel.socket().setSendBufferSize(sendBufferSize) Some(socketChannel) } catch { case e: TooManyConnectionsException => info(s"Rejected connection from ${e.ip}, address already has the configured maximum of ${e.count} connections.") close(endPoint.listenerName, socketChannel) None case e: ConnectionThrottledException => val ip = socketChannel.socket.getInetAddress debug(s"Delaying closing of connection from $ip for ${e.throttleTimeMs} ms") val endThrottleTimeMs = e.startThrottleTimeMs + e.throttleTimeMs throttledSockets += DelayedCloseSocket(socketChannel, endThrottleTimeMs) None } }
This thrown IOException is caught in the caller `acceptNewConnections` in line 706, which only prints an error message. The socketChannel that throws this IOException is not closed.
//core/src/main/scala/kafka/network/SocketServer.scala private def acceptNewConnections(): Unit = { val ready = nioSelector.select(500) if (ready > 0) { val keys = nioSelector.selectedKeys() val iter = keys.iterator() while (iter.hasNext && isRunning) { try { val key = iter.next iter.remove() if (key.isAcceptable) { accept(key).foreach { socketChannel => ... } while (!assignNewConnection(socketChannel, processor, retriesLeft == 0)) } } else throw new IllegalStateException("Unrecognized key state for acceptor thread.") } catch { case e: Throwable => error("Error while accepting connection", e) // line 706 } } } }
We found during testing this would cause our Kafka clients to experience errors (InvalidReplicationFactorException) for 40+ seconds when creating new topics. After 40 seconds, the clients would be able to create new topics successfully.
We check that after adding the socketChannel.close() upon IOException, the symptoms will disappear, so the clients do not need to wait for 40s to be working again.
Attachments
Issue Links
- relates to
-
HADOOP-18024 SocketChannel is not closed when IOException happens in Server$Listener.doAccept
-
- Reopened
-
- links to