For setting up Kafka Cluster for Multi Broker/ Server on single Machine follow below steps:
In below example we will create Kafka cluster with three brokers on single machine. All steps are same as configured for Kafka Cluster with Single Server on same machine additionally created two more file for additional brokers and run it on same Cluster.
Download and Installation
Download Latest version of Kafka from link download , copy it to installation directory and run below command to install it.
tar -zxvf kafka_2.11-0.10.0.0
Configuration Changes for Zookeeper and Server
Make below changes in zookeeper.properties configuration file in config directory.
clientPort is the port where client will connect. By Default port is 2181 if port will update in zookeeper.properties have to update in below server.properties too.
Make below changes in server.properties configuration file in config directory.
config/server.properties: broker.id=0 listeners=PLAINTEXT://:9092 log.dir=/tmp/kafka-logs zookeeper.connect=localhost:2181
By default server.properties file have above fields with default values.
broker.id : Represents broker unique id by which zookeeper recognize brokers in Kafka Cluster. If Kafka Cluster is having multiple server this broker id will in incremental order for servers.
listeners : Each broker runs on different port by default port for broker is 9092 and can change also.
log.dir: keep path of logs where Kafka will store steams records. By default point /tmp/kafka-logs.
For more change on property for server.properties file follow link Kafka Server Properties Configuration.
Multi Server/Broker :
For creating three brokers create two more copy of server.properties configuration file as server1.properties and server2.properties and make below changes in files so that configuration will ready with three brokers on Kafka cluster .
Create copy of server.properties file.
cp config/server.properties config/server1.properties cp config/server.properties config/server2.properties
make below changes corresponding to each configuration file.
config/server1.properties: broker.id=1 listeners=PLAINTEXT://:9093 log.dir=/tmp/kafka-logs-1 zookeeper.connect=localhost:2181 config/server2.properties: broker.id=2 listeners=PLAINTEXT://:9094 log.dir=/tmp/kafka-logs-2 zookeeper.connect=localhost:2181
Start Zookeeper and Servers
Run below files as below in Kafka directory
screen -d -m bin/zookeeper-server-start.sh config/zookeeper.properties screen -d -m bin/kafka-server-start.sh config/server.properties screen -d -m bin/kafka-server-start.sh config/server1.properties screen -d -m bin/kafka-server-start.sh config/server2.properties
Check status of Zookeeper & Servers
Below commands will return the port of Zookeeper and Servers processes Id
ps aux | grep zookeeper.properties ps aux | grep server.properties ps aux | grep server1.properties ps aux | grep server2.properties
Now Kafka is ready to create topic publish and subscribe messages also.
Create a Topic and Check Status
Create topic with user defined name and by passing replication and number partitions for topic. For more info about how partition stores in Kafka Cluster Env follow link for Kafka Introduction and Architecture.
bin/kafka-topics.sh --create --zookeeper localhost:2181 --replication-factor 3 --partitions 1 --topic multi-test Result: Created topic "multi-test".
above command will create a topic multi-test with configured partition as 1 and replica as 3.
List of available Topics in Zookeeper
Run below command to get list of topics
bin/kafka-topics.sh --list --zookeeper localhost:2181 Result: test multi-test
Description of Topic
bin/kafka-topics.sh --describe --zookeeper localhost:2181 --topic multi-test Result: Topic:multi-test PartitionCount:1 ReplicationFactor:3 Configs: Topic: multi-test Partition: 0 Leader: 2 Replicas: 2,0,1 Isr: 2,0,1
In above command response .The first line gives a summary of all the partitions, each additional line provide information about one partition. We have only one line for this topic because there is one partition.
- “leader” is the broker responsible for all reads and writes for the given partition. Each broker will be the leader for a randomly selected portion of the partitions.
- “replicas” is the list of brokers that replicate the log for this partition regardless of whether they are the leader or even if they are currently alive.
- “isr” is the set of “in-sync” replicas. This is the subset of the replicas list that is currently alive and caught-up to the leader.
In above example broker 2 is the leader for one partition for the topic and replicas of these portion are stored on broker 0 and then 1. If any message publish for topic will store in partition 2 first then in brokers 0 and 1 in sequence.
For all the request for this topic will taken care by Broker 2 and if broker is busy or fail by some reason like shutdown then broker 0 will become lead. See below example I have stopped broker 2 and run below command again and there lead is showing as 0.
bin/kafka-topics.sh --describe --zookeeper localhost:2181 --topic multi-test Topic:multi-test PartitionCount:1 ReplicationFactor:3 Configs: Topic: multi-test Partition: 0 Leader: 0 Replicas: 2,0,1 Isr: 0,1
Publish Messages to Topic
To test topic push your messages to topic by running below command
bin/kafka-console-producer.sh --broker-list localhost:9092 --topic multi-test Input Messages: Hi Dear How r u doing? Where are u these days?
These message after publish to Topic will retain as logs retention is configured for server even it’s read by consumer or not. To get information about Retention Policy configuration follow link Kafka Server Properties Configuration.
Subscribe Messages by Consumer from Topic
Run below command to get all published messages from multi-test Topic. It will return all these messages from beginning.
bin/kafka-console-consumer.sh --zookeeper localhost:2181 --from-beginning --topic multi-test Output Messages: Hi Dear How r u doing? Where are u these days?
Let me know your thought on this post.
Happy Learning !!!
Read More on Kafka
- Kafka Introduction and Architecture
- Kafka Server Properties Configuration
- Setup Kafka Cluster for Single Server/Broker
- Integrate Java with Kafka
- Integrate Logstash with Kafka
- Integrate Filebeat with Kafka
- Kafka and Zookeeper Common Issues