Dockerfile for Kafka

Index

• Introduction
• Deployment example
• Image explained

Introduction

This project contains a Dockerfile that creates an image that does not start an embedded Zookeeper. The image relies on a Zookeeper to be present. This enables cluster deployments without hassle (the number of ZooKeeper instances is unrelated to the number of Kafka instances).

The image bootstraps the configuration files automatically (first run) and additionally merges this with the provided environment variables.

Example

The image expects three volumes to be defined, and any environment variables meant for Kafka must be prefixed with KAFKA.. For example:

#!/bin/bash
echo "About to start Kafka-1 as docker container..."
docker run --detach \
    --name kafka-1 \
    --restart yes \
    --network="kafka-cluster" \
    --ip="192.168.100.100" \
    --volume /var/data/kafka1/config:/etc/kafka/install/config \
    --volume /var/data/kafka1/data:/etc/kafka/install/data \
    --volume /var/data/kafka1/logs:/etc/kafka/install/logs \
    --env "KAFKA.BROKER.ID=1" \
    --env "KAFKA.ZOOKEEPER.CONNECT=192.168.100.10:2181,192.168.100.11:2181,192.168.100.12:2181" \
    --env "KAFKA.WHAT.EVER=value" \
    technolords/kafka:latest
echo "...done!"

The data volume contains the log.dirs (i.e. topic data) while the logs volume contains the Kafka logging itself (i.e. log4j).

Using the example above will create a what.ever=value entry in the server.properties file.

For more properties, see:

• https://github.com/apache/kafka/blob/trunk/config/server.properties