(Ive been testing against the latest from github as 0.10.1.1 is too buggy) Seeing quite a few of these this morning:
2017-01-01 16:56:53,299 [StreamThread-1] DEBUG o.a.kafka.common.network.Selector - Connection with /<ip address> disconnected java.io.EOFException: null at org.apache.kafka.common.network.NetworkReceive.readFromReadableChannel(NetworkReceive.java:83) at org.apache.kafka.common.network.NetworkReceive.readFrom(NetworkReceive.java:71) at org.apache.kafka.common.network.KafkaChannel.receive(KafkaChannel.java:169) at org.apache.kafka.common.network.KafkaChannel.read(KafkaChannel.java:150) at org.apache.kafka.common.network.Selector.pollSelectionKeys(Selector.java:355) at org.apache.kafka.common.network.Selector.poll(Selector.java:303) at org.apache.kafka.clients.NetworkClient.poll(NetworkClient.java:341) at org.apache.kafka.clients.consumer.internals.ConsumerNetworkClient.poll(ConsumerNetworkClient.java:235) at org.apache.kafka.clients.consumer.internals.ConsumerNetworkClient.poll(ConsumerNetworkClient.java:181) at org.apache.kafka.clients.consumer.internals.AbstractCoordinator.joinGroupIfNeeded(AbstractCoordinator.java:309) at org.apache.kafka.clients.consumer.internals.AbstractCoordinator.ensureActiveGroup(AbstractCoordinator.java:278) at org.apache.kafka.clients.consumer.internals.ConsumerCoordinator.poll(ConsumerCoordinator.java:261) at org.apache.kafka.clients.consumer.KafkaConsumer.pollOnce(KafkaConsumer.java:1039) at org.apache.kafka.clients.consumer.KafkaConsumer.poll(KafkaConsumer.java:1004) at org.apache.kafka.streams.processor.internals.StreamThread.runLoop(StreamThread.java:570) at org.apache.kafka.streams.processor.internals.StreamThread.run(StreamThread.java:359)