I forgot to include some information about this problem. When I sent the produce request, the following appeared in server.log:
[2016-01-10 23:03:44,957] ERROR [KafkaApi-3] error when handling request Name: ProducerRequest; Version: 0; CorrelationId: 1; ClientId: null; RequiredAcks: 1; AckTimeoutMs: 10000 ms; TopicAndPartition: [topic_1,3] -> 37 (kafka.server.KafkaApis) java.lang.NullPointerException at org.apache.kafka.common.metrics.JmxReporter.getMBeanName(JmxReporter.java:127) at org.apache.kafka.common.metrics.JmxReporter.addAttribute(JmxReporter.java:106) at org.apache.kafka.common.metrics.JmxReporter.metricChange(JmxReporter.java:76) at org.apache.kafka.common.metrics.Metrics.registerMetric(Metrics.java:288) at org.apache.kafka.common.metrics.Sensor.add(Sensor.java:177) at org.apache.kafka.common.metrics.Sensor.add(Sensor.java:162) at kafka.server.ClientQuotaManager.getOrCreateQuotaSensors(ClientQuotaManager.scala:209) at kafka.server.ClientQuotaManager.recordAndMaybeThrottle(ClientQuotaManager.scala:111) at kafka.server.KafkaApis.kafka$server$KafkaApis$$sendResponseCallback$2(KafkaApis.scala:353) at kafka.server.KafkaApis$$anonfun$handleProducerRequest$1.apply(KafkaApis.scala:371) at kafka.server.KafkaApis$$anonfun$handleProducerRequest$1.apply(KafkaApis.scala:371) at kafka.server.ReplicaManager.appendMessages(ReplicaManager.scala:348) at kafka.server.KafkaApis.handleProducerRequest(KafkaApis.scala:366) at kafka.server.KafkaApis.handle(KafkaApis.scala:68) at kafka.server.KafkaRequestHandler.run(KafkaRequestHandler.scala:60) at java.lang.Thread.run(Thread.java:745) Later when I tried sending another produce request I got a somewhat similar error: [2016-01-11 08:15:05,153] ERROR [KafkaApi-3] error when handling request Name: ProducerRequest; Version: 0; CorrelationId: 1; ClientId: null; RequiredAcks: 1; AckTimeoutMs: 10000 ms; TopicAndPartition: [topic_1,3] -> 37 (kafka.server.KafkaApis) java.lang.IllegalArgumentException: A metric named 'MetricName [name=throttle-time, group=Produce, description=Tracking average throttle-time per client, tags={client-id=null}]' already exists, can't register another one. at org.apache.kafka.common.metrics.Metrics.registerMetric(Metrics.java:285) at org.apache.kafka.common.metrics.Sensor.add(Sensor.java:177) at org.apache.kafka.common.metrics.Sensor.add(Sensor.java:162) at kafka.server.ClientQuotaManager.getOrCreateQuotaSensors(ClientQuotaManager.scala:209) at kafka.server.ClientQuotaManager.recordAndMaybeThrottle(ClientQuotaManager.scala:111) at kafka.server.KafkaApis.kafka$server$KafkaApis$$sendResponseCallback$2(KafkaApis.scala:353) at kafka.server.KafkaApis$$anonfun$handleProducerRequest$1.apply(KafkaApis.scala:371) at kafka.server.KafkaApis$$anonfun$handleProducerRequest$1.apply(KafkaApis.scala:371) at kafka.server.ReplicaManager.appendMessages(ReplicaManager.scala:348) at kafka.server.KafkaApis.handleProducerRequest(KafkaApis.scala:366) at kafka.server.KafkaApis.handle(KafkaApis.scala:68) at kafka.server.KafkaRequestHandler.run(KafkaRequestHandler.scala:60) at java.lang.Thread.run(Thread.java:745) In both cases I was running kafka-console-consumer.sh to consume messages from the topic I was sending to, and the consumer did see the message I sent. Dave -----Original Message----- From: d...@dspeterson.com Sent: Monday, January 11, 2016 12:32am To: users@kafka.apache.org Subject: trouble sending produce requests to 0.9.0.0 broker cluster Hi, I'm having trouble sending produce requests to a Kafka 0.9.0.0 broker cluster consisting of 4 brokers with IDs 0, 1, 2, and 3. All 4 brokers are running locally on my CentOS 7 development box, listening on ports 9092, 9093, 9094, and 9095 respectively. I am running my own producer code (Bruce, see https://github.com/ifwe/bruce), which works without problems with Kafka 0.8, but has problems with 0.9.0.0. When I send a produce request consisting of a single message, I often get a response consisting of error ACK -1 (Unknown, unexpected server error) although I have also seen other errors such as 6 (NotLeaderForPartition). During one observed instance of this behavior I saw the following: sent produce request -------------------- - single message set containing a single message - topic: "topic_1" - partition: 3 - empty key - value: "hello world" - API key: 0 (produce request) - API version: 0 - correlation ID: 1 - empty client ID - required ACKs: 1 - timeout: 10000 - message magic byte: 0 - message attributes: 0 (no compression) - destination broker ID: 3 received produce response ------------------------- - correlation ID: 1 - topic: "topic_1" - partition: 3 - error code: -1 I have included tcpdump output for the above request and response below. The topic/partition layout is as follows: $ bin/kafka-topics.sh --describe --zookeeper localhost:2181/kafka-0.9.0.0 Topic:topic_1 PartitionCount:4 ReplicationFactor:2 Configs: Topic: topic_1 Partition: 0 Leader: 0 Replicas: 0,1 Isr: 0,1 Topic: topic_1 Partition: 1 Leader: 1 Replicas: 1,2 Isr: 2,1 Topic: topic_1 Partition: 2 Leader: 2 Replicas: 2,3 Isr: 2,3 Topic: topic_1 Partition: 3 Leader: 3 Replicas: 3,0 Isr: 0,3 $ Does anyone have any ideas about what may be causing this behavior? Additionally, I was using tcpdump to watch communication between kafka-console-producer.sh and the broker cluster, and noticed that the console producer sends a value of 1 for the API version in its produce requests. Is there any documentation describing protocol changes between API versions 0 and 1? I looked here: https://cwiki.apache.org/confluence/display/KAFKA/A+Guide+To+The+Kafka+Protocol and didn't see anything about the new API version. Any help is much appreciated. Thanks, Dave Produce request... # tcpdump -i lo -X -s 0 -nn src port 51147 tcpdump: verbose output suppressed, use -v or -vv for full protocol decode listening on lo, link-type EN10MB (Ethernet), capture size 65535 bytes 23:03:44.947589 IP 127.0.0.1.51147 > 127.0.0.1.9095: Flags [P.], seq 2040824198:2040824280, ack 1758705421, win 342, options [nop,nop,TS val 71321820 ecr 71222139], length 82 0x0000: 4500 0086 4300 4000 4006 f96f 7f00 0001 E...C.@.@..o.... 0x0010: 7f00 0001 c7cb 2387 79a4 8186 68d3 b70d ......#.y...h... 0x0020: 8018 0156 fe7a 0000 0101 080a 0440 48dc ...V.z.......@H. 0x0030: 043e c37b 0000 004e 0000 0000 0000 0001 .>.{...N........ 0x0040: ffff 0001 0000 2710 0000 0001 0007 746f ......'.......to 0x0050: 7069 635f 3100 0000 0100 0000 0300 0000 pic_1........... 0x0060: 2500 0000 0000 0000 0000 0000 1973 acf7 %............s.. 0x0070: 7c00 00ff ffff ff00 0000 0b68 656c 6c6f |..........hello 0x0080: 2077 6f72 6c64 .world 23:03:44.956525 IP 127.0.0.1.51147 > 127.0.0.1.9095: Flags [.], ack 40, win 342, options [nop,nop,TS val 71321830 ecr 71321830], length 0 0x0000: 4500 0034 4301 4000 4006 f9c0 7f00 0001 E..4C.@.@....... 0x0010: 7f00 0001 c7cb 2387 79a4 81d8 68d3 b734 ......#.y...h..4 0x0020: 8010 0156 fe28 0000 0101 080a 0440 48e6 ...V.(.......@H. 0x0030: 0440 48e6 .@H. ^C 2 packets captured 4 packets received by filter 0 packets dropped by kernel # Produce response... # tcpdump -i lo -X -s 0 -nn dst port 51147 tcpdump: verbose output suppressed, use -v or -vv for full protocol decode listening on lo, link-type EN10MB (Ethernet), capture size 65535 bytes 23:03:44.947661 IP 127.0.0.1.9095 > 127.0.0.1.51147: Flags [.], ack 2040824280, win 32742, options [nop,nop,TS val 71321821 ecr 71321820], length 0 0x0000: 4500 0034 7476 4000 4006 c84b 7f00 0001 E..4tv@.@..K.... 0x0010: 7f00 0001 2387 c7cb 68d3 b70d 79a4 81d8 ....#...h...y... 0x0020: 8010 7fe6 fe28 0000 0101 080a 0440 48dd .....(.......@H. 0x0030: 0440 48dc .@H. 23:03:44.956499 IP 127.0.0.1.9095 > 127.0.0.1.51147: Flags [P.], seq 0:39, ack 1, win 32742, options [nop,nop,TS val 71321830 ecr 71321820], length 39 0x0000: 4500 005b 7477 4000 4006 c823 7f00 0001 E..[tw@.@..#.... 0x0010: 7f00 0001 2387 c7cb 68d3 b70d 79a4 81d8 ....#...h...y... 0x0020: 8018 7fe6 fe4f 0000 0101 080a 0440 48e6 .....O.......@H. 0x0030: 0440 48dc 0000 0023 0000 0001 0000 0001 .@H....#........ 0x0040: 0007 746f 7069 635f 3100 0000 0100 0000 ..topic_1....... 0x0050: 03ff ffff ffff ffff ffff ff ........... ^C 2 packets captured 4 packets received by filter 0 packets dropped by kernel #