launching multiple kafka broker fails - kubernetes

Question

The repo used is: https://github.com/Yolean/kubernetes-kafka/
So I'm trying to run a Kafka cluster that connects to a Zookeeper cluster in Kubernetes, the first pod runs alright, but then the second Kafka pod tries to connect to the zookeeper cluster and it has this error:
kafka.common.InconsistentBrokerIdException: Configured broker.id 1
doesn't match stored broker.id 0 in meta.properties. If you moved your
data, make sure your configured broker.id matches. If you intend to
create a new broker, you should remove all data in your data
directories (log.dirs).
I understand the error is in the second broker id but shouldn't the zookeeper cluster allow multiple broker connections? or how could the config be changed to allow it?
or is it a Kafka configuration problem? The config file is:
kind: ConfigMap
metadata:
name: broker-config
namespace: whitenfv
labels:
name: kafka
system: whitenfv
apiVersion: v1
data:
init.sh: |-
#!/bin/bash
set -x
cp /etc/kafka-configmap/log4j.properties /etc/kafka/
KAFKA_BROKER_ID=${HOSTNAME##*-}
SEDS=("s/#init#broker.id=#init#/broker.id=$KAFKA_BROKER_ID/")
LABELS="kafka-broker-id=$KAFKA_BROKER_ID"
ANNOTATIONS=""
hash kubectl 2>/dev/null || {
SEDS+=("s/#init#broker.rack=#init#/#init#broker.rack=# kubectl not found in path/")
} && {
ZONE=$(kubectl get node "$NODE_NAME" -o=go-template='{{index .metadata.labels "failure-domain.beta.kubernetes.io/zone"}}')
if [ $? -ne 0 ]; then
SEDS+=("s/#init#broker.rack=#init#/#init#broker.rack=# zone lookup failed, see -c init-config logs/")
elif [ "x$ZONE" == "x<no value>" ]; then
SEDS+=("s/#init#broker.rack=#init#/#init#broker.rack=# zone label not found for node $NODE_NAME/")
else
SEDS+=("s/#init#broker.rack=#init#/broker.rack=$ZONE/")
LABELS="$LABELS kafka-broker-rack=$ZONE"
fi
OUTSIDE_HOST=$(kubectl get node "$NODE_NAME" -o jsonpath='{.status.addresses[?(#.type=="InternalIP")].address}')
if [ $? -ne 0 ]; then
echo "Outside (i.e. cluster-external access) host lookup command failed"
else
OUTSIDE_PORT=3240${KAFKA_BROKER_ID}
SEDS+=("s|#init#advertised.listeners=OUTSIDE://#init#|advertised.listeners=OUTSIDE://${OUTSIDE_HOST}:${OUTSIDE_PORT}|")
ANNOTATIONS="$ANNOTATIONS kafka-listener-outside-host=$OUTSIDE_HOST kafka-listener-outside-port=$OUTSIDE_PORT"
fi
if [ ! -z "$LABELS" ]; then
kubectl -n $POD_NAMESPACE label pod $POD_NAME $LABELS || echo "Failed to label $POD_NAMESPACE.$POD_NAME - RBAC issue?"
fi
if [ ! -z "$ANNOTATIONS" ]; then
kubectl -n $POD_NAMESPACE annotate pod $POD_NAME $ANNOTATIONS || echo "Failed to annotate $POD_NAMESPACE.$POD_NAME - RBAC issue?"
fi
}
printf '%s\n' "${SEDS[#]}" | sed -f - /etc/kafka-configmap/server.properties > /etc/kafka/server.properties.tmp
[ $? -eq 0 ] && mv /etc/kafka/server.properties.tmp /etc/kafka/server.properties
server.properties: |-
############################# Log Basics #############################
# A comma seperated list of directories under which to store log files
# Overrides log.dir
log.dirs=/var/lib/kafka/data/topics
# The default number of log partitions per topic. More partitions allow greater
# parallelism for consumption, but this will also result in more files across
# the brokers.
num.partitions=1
default.replication.factor=3
min.insync.replicas=2
auto.create.topics.enable=true
# The number of threads per data directory to be used for log recovery at startup and flushing at shutdown.
# This value is recommended to be increased for installations with data dirs located in RAID array.
#num.recovery.threads.per.data.dir=1
############################# Server Basics #############################
# The id of the broker. This must be set to a unique integer for each broker.
#init#broker.id=#init#
#init#broker.rack=#init#
############################# Socket Server Settings #############################
# The address the socket server listens on. It will get the value returned from
# java.net.InetAddress.getCanonicalHostName() if not configured.
# FORMAT:
# listeners = listener_name://host_name:port
# EXAMPLE:
# listeners = PLAINTEXT://your.host.name:9092
#listeners=PLAINTEXT://:9092
listeners=OUTSIDE://:9094,PLAINTEXT://:9092
# Hostname and port the broker will advertise to producers and consumers. If not set,
# it uses the value for "listeners" if configured. Otherwise, it will use the value
# returned from java.net.InetAddress.getCanonicalHostName().
#advertised.listeners=PLAINTEXT://your.host.name:9092
#init#advertised.listeners=OUTSIDE://#init#,PLAINTEXT://:9092
# Maps listener names to security protocols, the default is for them to be the same. See the config documentation for more details
#listener.security.protocol.map=PLAINTEXT:PLAINTEXT,SSL:SSL,SASL_PLAINTEXT:SASL_PLAINTEXT,SASL_SSL:SASL_SSL
listener.security.protocol.map=PLAINTEXT:PLAINTEXT,SSL:SSL,SASL_PLAINTEXT:SASL_PLAINTEXT,SASL_SSL:SASL_SSL,OUTSIDE:PLAINTEXT
inter.broker.listener.name=PLAINTEXT
# The number of threads that the server uses for receiving requests from the network and sending responses to the network
#num.network.threads=3
# The number of threads that the server uses for processing requests, which may include disk I/O
#num.io.threads=8
# The send buffer (SO_SNDBUF) used by the socket server
#socket.send.buffer.bytes=102400
# The receive buffer (SO_RCVBUF) used by the socket server
#socket.receive.buffer.bytes=102400
# The maximum size of a request that the socket server will accept (protection against OOM)
#socket.request.max.bytes=104857600
############################# Internal Topic Settings #############################
# The replication factor for the group metadata internal topics "__consumer_offsets" and "__transaction_state"
# For anything other than development testing, a value greater than 1 is recommended for to ensure availability such as 3.
#offsets.topic.replication.factor=1
#transaction.state.log.replication.factor=1
#transaction.state.log.min.isr=1
############################# Log Flush Policy #############################
# Messages are immediately written to the filesystem but by default we only fsync() to sync
# the OS cache lazily. The following configurations control the flush of data to disk.
# There are a few important trade-offs here:
# 1. Durability: Unflushed data may be lost if you are not using replication.
# 2. Latency: Very large flush intervals may lead to latency spikes when the flush does occur as there will be a lot of data to flush.
# 3. Throughput: The flush is generally the most expensive operation, and a small flush interval may lead to excessive seeks.
# The settings below allow one to configure the flush policy to flush data after a period of time or
# every N messages (or both). This can be done globally and overridden on a per-topic basis.
# The number of messages to accept before forcing a flush of data to disk
#log.flush.interval.messages=10000
# The maximum amount of time a message can sit in a log before we force a flush
#log.flush.interval.ms=1000
############################# Log Retention Policy #############################
# The following configurations control the disposal of log segments. The policy can
# be set to delete segments after a period of time, or after a given size has accumulated.
# A segment will be deleted whenever *either* of these criteria are met. Deletion always happens
# from the end of the log.
# https://cwiki.apache.org/confluence/display/KAFKA/KIP-186%3A+Increase+offsets+retention+default+to+7+days
offsets.retention.minutes=10080
# The minimum age of a log file to be eligible for deletion due to age
log.retention.hours=-1
# A size-based retention policy for logs. Segments are pruned from the log unless the remaining
# segments drop below log.retention.bytes. Functions independently of log.retention.hours.
#log.retention.bytes=1073741824
# The maximum size of a log segment file. When this size is reached a new log segment will be created.
#log.segment.bytes=1073741824
# The interval at which log segments are checked to see if they can be deleted according
# to the retention policies
#log.retention.check.interval.ms=300000
############################# Zookeeper #############################
# Zookeeper connection string (see zookeeper docs for details).
# This is a comma separated host:port pairs, each corresponding to a zk
# server. e.g. "127.0.0.1:3000,127.0.0.1:3001,127.0.0.1:3002".
# You can also append an optional chroot string to the urls to specify the
# root directory for all kafka znodes.
zookeeper.connect=zoo-0.zoo:2181,zoo-1.zoo:2181,zoo-2.zoo:2181
# Timeout in ms for connecting to zookeeper
#zookeeper.connection.timeout.ms=6000
############################# Group Coordinator Settings #############################
# The following configuration specifies the time, in milliseconds, that the GroupCoordinator will delay the initial consumer rebalance.
# The rebalance will be further delayed by the value of group.initial.rebalance.delay.ms as new members join the group, up to a maximum of max.poll.interval.ms.
# The default value for this is 3 seconds.
# We override this to 0 here as it makes for a better out-of-the-box experience for development and testing.
# However, in production environments the default value of 3 seconds is more suitable as this will help to avoid unnecessary, and potentially expensive, rebalances during application startup.
#group.initial.rebalance.delay.ms=0
log4j.properties: |-
# Unspecified loggers and loggers with additivity=true output to server.log and stdout
# Note that INFO only applies to unspecified loggers, the log level of the child logger is used otherwise
log4j.rootLogger=INFO, stdout
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=[%d] %p %m (%c)%n
log4j.appender.kafkaAppender=org.apache.log4j.DailyRollingFileAppender
log4j.appender.kafkaAppender.DatePattern='.'yyyy-MM-dd-HH
log4j.appender.kafkaAppender.File=${kafka.logs.dir}/server.log
log4j.appender.kafkaAppender.layout=org.apache.log4j.PatternLayout
log4j.appender.kafkaAppender.layout.ConversionPattern=[%d] %p %m (%c)%n
log4j.appender.stateChangeAppender=org.apache.log4j.DailyRollingFileAppender
log4j.appender.stateChangeAppender.DatePattern='.'yyyy-MM-dd-HH
log4j.appender.stateChangeAppender.File=${kafka.logs.dir}/state-change.log
log4j.appender.stateChangeAppender.layout=org.apache.log4j.PatternLayout
log4j.appender.stateChangeAppender.layout.ConversionPattern=[%d] %p %m (%c)%n
log4j.appender.requestAppender=org.apache.log4j.DailyRollingFileAppender
log4j.appender.requestAppender.DatePattern='.'yyyy-MM-dd-HH
log4j.appender.requestAppender.File=${kafka.logs.dir}/kafka-request.log
log4j.appender.requestAppender.layout=org.apache.log4j.PatternLayout
log4j.appender.requestAppender.layout.ConversionPattern=[%d] %p %m (%c)%n
log4j.appender.cleanerAppender=org.apache.log4j.DailyRollingFileAppender
log4j.appender.cleanerAppender.DatePattern='.'yyyy-MM-dd-HH
log4j.appender.cleanerAppender.File=${kafka.logs.dir}/log-cleaner.log
log4j.appender.cleanerAppender.layout=org.apache.log4j.PatternLayout
log4j.appender.cleanerAppender.layout.ConversionPattern=[%d] %p %m (%c)%n
log4j.appender.controllerAppender=org.apache.log4j.DailyRollingFileAppender
log4j.appender.controllerAppender.DatePattern='.'yyyy-MM-dd-HH
log4j.appender.controllerAppender.File=${kafka.logs.dir}/controller.log
log4j.appender.controllerAppender.layout=org.apache.log4j.PatternLayout
log4j.appender.controllerAppender.layout.ConversionPattern=[%d] %p %m (%c)%n
log4j.appender.authorizerAppender=org.apache.log4j.DailyRollingFileAppender
log4j.appender.authorizerAppender.DatePattern='.'yyyy-MM-dd-HH
log4j.appender.authorizerAppender.File=${kafka.logs.dir}/kafka-authorizer.log
log4j.appender.authorizerAppender.layout=org.apache.log4j.PatternLayout
log4j.appender.authorizerAppender.layout.ConversionPattern=[%d] %p %m (%c)%n
# Change the two lines below to adjust ZK client logging
log4j.logger.org.I0Itec.zkclient.ZkClient=INFO
log4j.logger.org.apache.zookeeper=INFO
# Change the two lines below to adjust the general broker logging level (output to server.log and stdout)
log4j.logger.kafka=INFO
log4j.logger.org.apache.kafka=INFO
# Change to DEBUG or TRACE to enable request logging
log4j.logger.kafka.request.logger=WARN, requestAppender
log4j.additivity.kafka.request.logger=false
# Uncomment the lines below and change log4j.logger.kafka.network.RequestChannel$ to TRACE for additional output
# related to the handling of requests
#log4j.logger.kafka.network.Processor=TRACE, requestAppender
#log4j.logger.kafka.server.KafkaApis=TRACE, requestAppender
#log4j.additivity.kafka.server.KafkaApis=false
log4j.logger.kafka.network.RequestChannel$=WARN, requestAppender
log4j.additivity.kafka.network.RequestChannel$=false
log4j.logger.kafka.controller=TRACE, controllerAppender
log4j.additivity.kafka.controller=false
log4j.logger.kafka.log.LogCleaner=INFO, cleanerAppender
log4j.additivity.kafka.log.LogCleaner=false
log4j.logger.state.change.logger=TRACE, stateChangeAppender
log4j.additivity.state.change.logger=false
# Change to DEBUG to enable audit log for the authorizer
log4j.logger.kafka.authorizer.logger=WARN, authorizerAppender
log4j.additivity.kafka.authorizer.logger=false

Answer 1

As per this: Launching multiple Kafka brokers fails, it's an issue with log.dirs in your server.properties where it can't be the same for all your brokers or it can't be shared.
You can probably use the ${HOSTNAME##*-} bash environment setting to modify your container entrypoint script that in of itself modifies your server.properties before the start, but the downside of that is that you are going to have to rebuild your Docker image.
Another strategy using StatefulSets is described here: How to pass args to pods based on Ordinal Index in StatefulSets?. But you will also have to make changes on how the Kafka entrypoint is called.
You could also try using completely different volumes for each of your Kafka broker pods.

Answer 2

First you must see the server configuration in the server.properties file.
~/kafka_2.11-2.1.0/bin$ egrep -v '^#|^$' ../config/server.properties
broker.id=0
num.network.threads=3
num.io.threads=8
socket.send.buffer.bytes=102400
socket.receive.buffer.bytes=102400
socket.request.max.bytes=104857600
log.dirs=/tmp/kafka-logs
...
Here you can see an attribute called log.dirs and a directory /tmp/kafka-logs as a value. Make sure that the directory has the right permissions for the user you are using to start the Kafka process.
~/kafka_2.11-2.1.0/bin$ ls -lrtd /tmp/kafka-logs
drwxr-xr-x 2 kafkauser kafkauser 4096 mar 1 08:26 /tmp/kafka-logs
Rremove all files under /tmp/kafka-logs
~/kafka_2.11-2.1.0/bin$ rm -fr /tmp/kafka-logs/*
And finally try again. Probably your problem is solved.