I run 1 kafka and 3 zookeeper-server in docker on kubernetes following this instruction. I cannot produce/consume topics outside pod(docker container).
bin/kafka-console-producer.sh --broker-list 1.2.3.4:9092 --topic
[2016-06-11 15:14:46,889] ERROR Error when sending message to topic test with key: null, value: 3 bytes with error: (org.apache.kafka.clients.producer.internals.ErrorLoggingCallback)
org.apache.kafka.common.errors.TimeoutException: Batch containing 3 record(s) expired due to timeout while requesting metadata from brokers for test-0
bin/kafka-console-consumer.sh --zookeeper 5.6.7.8:2181 --topic test --from-beginning
[2016-06-11 15:15:58,985] WARN Fetching topic metadata with correlation id 0 for topics [Set(test)] from broker [BrokerEndPoint(1001,kafka-service,9092)] failed (kafka.client.ClientUtils$)
java.nio.channels.ClosedChannelException
at kafka.network.BlockingChannel.send(BlockingChannel.scala:110)
at kafka.producer.SyncProducer.liftedTree1$1(SyncProducer.scala:80)
at kafka.producer.SyncProducer.kafka$producer$SyncProducer$doSend(SyncProducer.scala:79)
at kafka.producer.SyncProducer.send(SyncProducer.scala:124)
at kafka.client.ClientUtils$.fetchTopicMetadata(ClientUtils.scala:59)
at kafka.client.ClientUtils$.fetchTopicMetadata(ClientUtils.scala:94)
at kafka.consumer.ConsumerFetcherManager$LeaderFinderThread.doWork(ConsumerFetcherManager.scala:66)
at kafka.utils.ShutdownableThread.run(ShutdownableThread.scala:63)
[2016-06-11 15:15:58,992] WARN [console-consumer-66869_tattoo-NV49C-1465629357799-ce1529da-leader-finder-thread], Failed to find leader for Set([test,0]) (kafka.consumer.ConsumerFetcherManager$LeaderFinderThread)
kafka.common.KafkaException: fetching topic metadata for topics [Set(test)] from broker [ArrayBuffer(BrokerEndPoint(1001,kafka-service,9092))] failed
at kafka.client.ClientUtils$.fetchTopicMetadata(ClientUtils.scala:73)
at kafka.client.ClientUtils$.fetchTopicMetadata(ClientUtils.scala:94)
at kafka.consumer.ConsumerFetcherManager$LeaderFinderThread.doWork(ConsumerFetcherManager.scala:66)
at kafka.utils.ShutdownableThread.run(ShutdownableThread.scala:63)
Caused by: java.nio.channels.ClosedChannelException
at kafka.network.BlockingChannel.send(BlockingChannel.scala:110)
at kafka.producer.SyncProducer.liftedTree1$1(SyncProducer.scala:80)
at kafka.producer.SyncProducer.kafka$producer$SyncProducer$doSend(SyncProducer.scala:79)
at kafka.producer.SyncProducer.send(SyncProducer.scala:124)
at kafka.client.ClientUtils$.fetchTopicMetadata(ClientUtils.scala:59)
... 3 more
kafka log:
[2016-06-11 07:47:58,269] INFO [Kafka Server 1001], started (kafka.server.KafkaServer)
[2016-06-11 07:53:50,404] INFO [ReplicaFetcherManager on broker 1001] Removed fetcher for partitions [test,0] (kafka. server.ReplicaFetcherManager)
[2016-06-11 07:53:50,443] INFO Completed load of log test-0 with log end offset 0 (kafka.log.Log)
[2016-06-11 07:53:50,458] INFO Created log for partition [test,0] in /kafka/kafka-logs-kafka-controller-3rsv3 with properties {compression.type -> producer, message.format.version -> 0.10.0-IV1, file.delete.delay.ms -> 60000, max. message.bytes -> 1000012, message.timestamp.type -> CreateTime, min.insync.replicas -> 1, segment.jitter.ms -> 0, preallocate -> false, min.cleanable.dirty.ratio -> 0.5, index.interval.bytes -> 4096, unclean.leader.election.enable -> true, retention.bytes -> -1, delete.retention.ms -> 86400000, cleanup.policy -> delete, flush.ms -> 9223372036854775807, segment.ms -> 604800000, segment.bytes -> 1073741824, retention.ms -> 604800000, message. timestamp.difference.max.ms -> 9223372036854775807, segment.index.bytes -> 10485760, flush.messages -> 9223372036854775807}. (kafka.log.LogManager)
[2016-06-11 07:53:50,459] INFO Partition [test,0] on broker 1001: No checkpointed highwatermark is found for partition [test,0] (kafka.cluster.Partition)
[2016-06-11 07:57:57,955] INFO [Group Metadata Manager on Broker 1001]: Removed 0 expired offsets in 0 milliseconds. ( kafka.coordinator.GroupMetadataManager)
And the config/server.properties
broker.id=-1
log.dirs=/kafka/kafka-logs-kafka-controller-3rsv3
num.partitions=1
zookeeper.connect=zookeeper-1:2181,zookeeper-2:2181,zookeeper-3:2181
zookeeper.connection.timeout.ms=6000
service.port.9092.tcp.addr=10.254.68.65
service.port.9092.tcp.proto=tcp
service.service.port.kafka.port=9092
service.service.port=9092
service.port=tcp://10.254.68.65:9092
service.port.9092.tcp.port=9092
version=0.10.0.0
service.service.host=10.254.68.65
port=9092
advertised.host.name=kafka-service
service.port.9092.tcp=tcp://10.254.68.65:9092
advertised.port=9092
But I can do bin/kafka-console-producer.sh --broker-list localhost:9092 --topic
and bin/kafka-console-consumer.sh --zookeeper 5.6.7.8:2181 --topic test --from-beginning
if I am inside the pod (docker container).
And I can create and list topics normally when connecting to zookeeper's service:
bin/kafka-topics.sh --describe --zookeeper 5.6.7.8:2181 --topic test
Topic:test PartitionCount:1 ReplicationFactor:1 Configs:
Topic: test Partition: 0 Leader: 1001 Replicas: 1001 Isr: 1001
And my yaml file for creating kafka replicaiton-congtroller and service:
---
apiVersion: v1
kind: Service
metadata:
name: kafka-service2
labels:
app: kafka2
spec:
clusterIP: None
ports:
- port: 9092
name: kafka-port
targetPort: 9092
protocol: TCP
selector:
app: kafka2
---
apiVersion: v1
kind: ReplicationController
metadata:
name: kafka-controller2
spec:
replicas: 1
selector:
app: kafka2
template:
metadata:
labels:
app: kafka2
spec:
containers:
- name: kafka2
image: wurstmeister/kafka
ports:
- containerPort: 9092
env:
- name: KAFKA_ADVERTISED_PORT
value: "9092"
- name: KAFKA_ADVERTISED_HOST_NAME
value: kafka-service2
- name: KAFKA_ZOOKEEPER_CONNECT
value: zoo1:2181,zoo2:2181,zoo3:2181
Kafka register to zookeeper with its service's name. And consuming/producing messages need access to the service names(here is dns records on zookeeper-1, zookeeper-2, zookeeper-3), which are only accessible through kubernetes' dns. So only application running on kubernetes can access my kafka. Therefore I cannot use the external IP of kafka-service or port-forwarding the kafka pod to localhost and then access it.
But why can I create, list and describe topics outside kubernetes cluster? I guess it is because zookeepers can do those operation by themselves. But consuming/producing message will need access to the ADVERTISED_HOST_NAME provided by kafka.