I am currently trying to expose Kafka outside of the Kubernetes cluster. And currently, it is working very randomly. Whenever I update the Kafka cluster using yaml file, sometimes it can consume and produce correctly, but sometimes it doesn't. This happens whenever I do rolling-update. The current pattern is that every second time that I try to re-update. It does not work. So it connects correctly with 50% chance. I am assuming I still have some issue in port mapping.
Here is my load balancer (currently using ebs):
spec:
selector:
app: kafka
ports:
- protocol: TCP
port: 31492
nodePort: 31492
targetPort: 9093
type: LoadBalancer
Here is my kafka:
apiVersion: apps/v1
kind: StatefulSet
metadata:
name: kafka
spec:
selector:
matchLabels:
app: kafka
serviceName: "kafka-svc"
replicas: 3
template:
metadata:
labels:
app: kafka
spec:
terminationGracePeriodSeconds: 100
affinity:
podAntiAffinity:
requiredDuringSchedulingIgnoredDuringExecution:
- labelSelector:
matchExpressions:
- key: "app"
operator: In
values:
- kafka
topologyKey: "kubernetes.io/hostname"
podAffinity:
preferredDuringSchedulingIgnoredDuringExecution:
- weight: 1
podAffinityTerm:
labelSelector:
matchExpressions:
- key: "app"
operator: In
values:
- zk
topologyKey: "kubernetes.io/hostname"
containers:
- name: kafka
imagePullPolicy: Always
image: gcr.io/google_samples/k8skafka:v1
resources:
requests:
memory: "1Gi"
cpu: 500m
ports:
- containerPort: 9093
name: server
- containerPort: 31492
lifecycle:
preStop:
exec:
command: ["/bin/sh", "-c", "/opt/kafka/bin/kafka-server-stop.sh; sleep 3000"]
command:
- sh
- -c
- "exec kafka-server-start.sh /opt/kafka/config/server.properties --override broker.id=${HOSTNAME##*-} \
--override listeners='INTERNAL://0.0.0.0:9093,EXTERNAL://0.0.0.0:31492' \
--override listener.security.protocol.map='INTERNAL:PLAINTEXT,EXTERNAL:PLAINTEXT' \
--override advertised.listeners=INTERNAL://$(MY_POD_IP):9093,EXTERNAL://$(K8S_ELB_PORT_31492_TCP_ADDR):31492 \
--override inter.broker.listener.name=INTERNAL \
--override zookeeper.connect=zk-0.zk-svc.default.svc.cluster.local:2181,zk-1.zk-svc.default.svc.cluster.local:2181,zk-2.zk-svc.default.svc.cluster.local:2181 \
--override log.dir=/var/lib/kafka \
--override auto.create.topics.enable=true \
--override auto.leader.rebalance.enable=true \
--override background.threads=10 \
--override compression.type=producer \
--override delete.topic.enable=false \
--override leader.imbalance.check.interval.seconds=300 \
--override leader.imbalance.per.broker.percentage=10 \
--override log.flush.interval.messages=9223372036854775807 \
--override log.flush.offset.checkpoint.interval.ms=60000 \
--override log.flush.scheduler.interval.ms=9223372036854775807 \
--override log.retention.bytes=-1 \
--override log.retention.hours=168 \
--override log.roll.hours=168 \
--override log.roll.jitter.hours=0 \
--override log.segment.bytes=1073741824 \
--override log.segment.delete.delay.ms=60000 \
--override message.max.bytes=1000012 \
--override min.insync.replicas=1 \
--override num.io.threads=8 \
--override num.network.threads=3 \
--override num.recovery.threads.per.data.dir=1 \
--override num.replica.fetchers=1 \
--override offset.metadata.max.bytes=4096 \
--override offsets.commit.required.acks=-1 \
--override offsets.commit.timeout.ms=5000 \
--override offsets.load.buffer.size=5242880 \
--override offsets.retention.check.interval.ms=600000 \
--override offsets.retention.minutes=1440 \
--override offsets.topic.compression.codec=0 \
--override offsets.topic.num.partitions=50 \
--override offsets.topic.replication.factor=3 \
--override offsets.topic.segment.bytes=104857600 \
--override queued.max.requests=500 \
--override quota.consumer.default=9223372036854775807 \
--override quota.producer.default=9223372036854775807 \
--override replica.fetch.min.bytes=1 \
--override replica.fetch.wait.max.ms=500 \
--override replica.high.watermark.checkpoint.interval.ms=5000 \
--override replica.lag.time.max.ms=10000 \
--override replica.socket.receive.buffer.bytes=65536 \
--override replica.socket.timeout.ms=30000 \
--override request.timeout.ms=30000 \
--override socket.receive.buffer.bytes=102400 \
--override socket.request.max.bytes=104857600 \
--override socket.send.buffer.bytes=102400 \
--override unclean.leader.election.enable=true \
--override zookeeper.session.timeout.ms=6000 \
--override zookeeper.set.acl=false \
--override broker.id.generation.enable=true \
--override connections.max.idle.ms=600000 \
--override controlled.shutdown.enable=true \
--override controlled.shutdown.max.retries=3 \
--override controlled.shutdown.retry.backoff.ms=5000 \
--override controller.socket.timeout.ms=30000 \
--override default.replication.factor=1 \
--override fetch.purgatory.purge.interval.requests=1000 \
--override group.max.session.timeout.ms=300000 \
--override group.min.session.timeout.ms=6000 \
--override inter.broker.protocol.version=0.10.2-IV0 \
--override log.cleaner.backoff.ms=15000 \
--override log.cleaner.dedupe.buffer.size=134217728 \
--override log.cleaner.delete.retention.ms=86400000 \
--override log.cleaner.enable=true \
--override log.cleaner.io.buffer.load.factor=0.9 \
--override log.cleaner.io.buffer.size=524288 \
--override log.cleaner.io.max.bytes.per.second=1.7976931348623157E308 \
--override log.cleaner.min.cleanable.ratio=0.5 \
--override log.cleaner.min.compaction.lag.ms=0 \
--override log.cleaner.threads=1 \
--override log.cleanup.policy=delete \
--override log.index.interval.bytes=4096 \
--override log.index.size.max.bytes=10485760 \
--override log.message.timestamp.difference.max.ms=9223372036854775807 \
--override log.message.timestamp.type=CreateTime \
--override log.preallocate=false \
--override log.retention.check.interval.ms=300000 \
--override max.connections.per.ip=2147483647 \
--override num.partitions=1 \
--override producer.purgatory.purge.interval.requests=1000 \
--override replica.fetch.backoff.ms=1000 \
--override replica.fetch.max.bytes=1048576 \
--override replica.fetch.response.max.bytes=10485760 \
--override reserved.broker.max.id=1000 "
env:
- name: KAFKA_HEAP_OPTS
value : "-Xmx512M -Xms512M"
- name: KAFKA_OPTS
value: "-Dlogging.level=INFO"
- name: MY_POD_NAME
valueFrom:
fieldRef:
fieldPath: metadata.name
- name: MY_POD_NAMESPACE
valueFrom:
fieldRef:
fieldPath: metadata.namespace
- name: MY_POD_IP
valueFrom:
fieldRef:
fieldPath: status.podIP
volumeMounts:
- name: datadir
mountPath: /var/lib/kafka
readinessProbe:
exec:
command:
- sh
- -c
- "/opt/kafka/bin/kafka-broker-api-versions.sh --bootstrap-server=localhost:9093"
securityContext:
runAsUser: 1000
fsGroup: 1000
volumeClaimTemplates:
- metadata:
name: datadir
spec:
storageClassName: standard
accessModes: [ "ReadWriteOnce" ]
resources:
requests:
storage: 10Gi
For internal listener, I am assigning each pod's ip, but one concern is that it is using the secondary ip from the kafka aws instance. I am not sure whether that is okay. (Hopefully this makes sense) Is there any part that I missed to set up port mapping? I am mostly concerned about advertised listener for kafka.
The advertised listener must be unique per pod. If you are running multiple pods in your stateful set, you will need to have a external load balancer port or address dedicated to each broker, ie three replicas = three different load balancer ports. Then set the advertised listener for each pod to it's external port.