Combined Zookeeper and Kafka centos7 docker image
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krisgeus Merge pull request #7 from krisgeus/upgrade-kafka
Upgrade kafka and make starting more robust
Latest commit 2d75d87 Apr 5, 2018

Docker kafka plus zookeeper image

Building the image

docker build -f Dockerfile -t docker-kafka .

Configuring the image

Configuration of kafka can be changed/influenced by setting a set of environment variables

env var default options description
ADVERTISED_LISTENERS the listeners advertised to the outside world with associated listener name
LISTENERS the listeners being created by the broker with their associated name
SECURITY_PROTOCOL_MAP mapping from the listener names to security protocol
SSL_CERT Optional pem certificate
SSL_KEY Optional ssl private key
SSL_DN Optional subject to use for the generated certificate, e.g.,OU=data,O=example,L=Kris,S=Geus,C=NL
SSL_PASSWORD Optional password to use for the store and key otherwise will be automatically generated
INTER_BROKER the listener name the internal connections will use
LOG_RETENTION_HOURS 168 Number of hours the messages are kept in the topic log
LOG_RETENTION_BYTES 1073741824 Size of the topic logs at which pruning will take place
NUM_PARTITIONS 1 Default number of partitions for a topic
AUTO_CREATE_TOPICS true true, false Automatically create a topic when messages are produced
KAFKA_CREATE_TOPICS Comma separated list op topics to create. Topic can specify partitions, replication and cleanup.policy by appending a colon separated list of these configurations

Running the image

To run the image with 2 topics, advertising an internal (9092) and external listener (443). This example is useful when you have some kind of edge termination for ssl externally or port mapping, e.g. port 443 external SSL --> port 9092 internal.

docker run --rm -p 2181:2181 -p 9092:9092 -p 9093:9093 \
  --env ADVERTISED_LISTENERS=PLAINTEXT://kafka:443,INTERNAL://localhost:9093 \
  --env KAFKA_CREATE_TOPICS="test:36:1,krisgeus:12:1:compact" \
  --name kafka \


Testing if the image works can be done by using the kafka console producer/consumer since we named the image we need to add an entry to the /etc/hosts file to connect the name kafka to the local ip	kafka

Now we can use that hostname (the same as the advertised host) to connect the producer and consumer

kafka-console-producer --broker-list kafka:9092 \
  --topic test

Sending messages can be done by typeing the following in the console


To consume this use the following in a separate terminal window

kafka-console-consumer --bootstrap-server kafka:9092 \
  --topic test \

A compact topic needs a key so remember to start the producer with the mandatory parse.key and key.separator options!

kafka-console-producer --broker-list kafka:9092 \
  --topic krisgeus \
  --property "parse.key=true" \
  --property "key.separator=:"

Sending messages can be done by typeing the following in the console


To consume this use the following in a separate terminal window

kafka-console-consumer --bootstrap-server kafka:9092 \
  --topic krisgeus \

SSL key and cert example

  1. generate a private key
openssl genrsa -des3 -passout pass:apachepass -out pass.key 2048
openssl rsa -passin pass:apachepass -in pass.key -out ssl.key
  1. generate a cert
openssl req -new -key ssl.key -out fqdn.csr -subj "/C=/ST=/L=/O=/CN=domain”
  1. cert self-signing
openssl x509 -req -days 365 -in fqdn.csr -signkey ssl.key -out selfsign.crt
  1. passning a key and cert to the docker
--env SSL_CERT="`cat selfsign.crt`" \
--env SSL_KEY="`cat /ssl.key`" \
  1. generate a client truststore
keytool -import -alias localhost -keystore client.truststore.jks -file selfsign.crt -noprompt --storepass secretpass --keypass secretpass
  1. kafka client config

Kerberos consuming example

You can use the ticket cache or the keytab to configure


kinit kafka/$(hostname -f) -kt /kafka.keytab

vi /kafka-client.jaas

KafkaClient { required
export KAFKA_OPTS=""

${KAFKA_HOME}/ --bootstrap-server $(hostname):9092 --topic divolte --from-beginning --consumer-property security.protocol=SASL_PLAINTEXT


vi /kafka-client-keytab.jaas

KafkaClient { required
export KAFKA_OPTS=""

${KAFKA_HOME}/ --bootstrap-server $(hostname):9092 --topic divolte --from-beginning --consumer-property security.protocol=SASL_PLAINTEXT