Kafka single node setup

On a single machine, a 3 broker kafka instance is at best the minimum, for a hassle-free working. Also, replication factor is set to 2.

Say X,Y and Z are our kafka brokers. With replication factor 2, the data in X will be copied to both Y & Z, the data in Y will be copied to X & Z and the data of Z is copied to X & Y.

Prerequisites

• have java >= 1.8 installed.
• get binary distribution of Kafka from here .

Setup

Extract the contents of the kafka archive to a convenient place and cd into it. Use a terminal multiplexer to run the components that make the kafka eco-system.

Zookeeper

• Edit the config file config/server.properties and change the dataDir entry to some place that does not get wiped after a reboot. Ex:dataDir=/home/user/tmp/zookeeper
• Start the zookeeper instance with $ bin/zookeeper-server-start.sh config/zookeeper.properties

Kafka brokers

• In the config folder there would be a server.properties file. This is the kafka server's config file. We need 3 instances of kafka brokers.
• Make a copy. $ cp config/server.properties config/server.b1.properties
• In the copy make the following changes

broker.id=1  #unique id for our broker instance
port=9092    #port where it listens
delete.topic.enable=true   #if we want to delete kafka topic stored in broker
log.dirs=/home/thatcoder/kafka-logs/01  #to a place thats not volatile
advertised.host.name=10.0.0.81 #prevents leader not found error when connecting from remote machine

• Make 2 more copies of this file and change the fields broker.id, port and log.dirs for each file.
• Run the individual brokers like

$  bin/kafka-server-start.sh config/server.b1.properties
$  bin/kafka-server-start.sh config/server.b2.properties
$  bin/kafka-server-start.sh config/server.b3.properties

**Tip : ** Executing a $ jps on the shell would give all JVM instances. To kill the processes kill -9 <pid> would do the trick.

Testing out the install

• Create a topic with $ bin/kafka-topics.sh --create --zookeeper localhost:2181 --replication-factor 2 --partitions 3 --topic <topicname>
• Push data onto it $ bin/kafka-console-producer.sh --broker-list localhost:9092,localhost:9093,localhost:9094 --sync --topic <topicname>
• Fetch data from it $ bin/kafka-console-consumer.sh --zookeeper localhost:2181 --topic <topicname> --from-beginning

Program Setup

To start the application in development mode,

npm run dev

In production mode use,

npm start