Introduction
Apache Kafka is a popular distributed message broker designed to handle large volumes of real-time data. A Kafka cluster is highly scalable and fault-tolerant. It also has a much higher throughput compared to other message brokers like ActiveMQ and RabbitMQ. Though it is generally used as a publish/subscribe messaging system, a lot of organizations also use it for log aggregation because it offers persistent storage for published messages. How To Install Apache Kafka on Ubuntu
A publish/subscribe messaging system allows one or more producers to publish messages without considering the number of consumers or how they will process the messages. Subscribed clients are notified automatically about updates and the creation of new messages. This system is more efficient and scalable than systems where clients poll periodically to determine if new messages are available.
In this tutorial, you will install and use Apache Kafka 2.6.3 on Ubuntu 20.04.
Prerequisites
To follow along, you will need:
- One Ubuntu 20.04 server and a non-root user with sudo privileges. Follow the steps specified in this guide if you do not have a non-root user set up.
- At least 4GB of RAM on your server. Installations without this amount of RAM may cause the Kafka service to fail.
- OpenJDK 11 installed on your server. To install this version, follow our tutorial How To Install Java with APT on Ubuntu 20.04. Kafka is written in Java, so it requires a JVM.
Step 1 — Creating a User for Kafka
Because Kafka can handle requests over a network, your first step is to create a dedicated user for the service. This minimizes damage to your Ubuntu machine in the event that someone compromises the Kafka server. We will create a dedicated kafka user in this step.
Logged in as your non-root sudo user, create a user called kafka:
sudo adduser kafka
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Follow the prompts to set a password and create the kafka user.
Next, add the kafka user to the sudo group with the adduser command. You need these privileges to install Kafka’s dependencies:
sudo adduser kafka sudo
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Your kafka user is now ready. Log into the account using su:
su -l kafka
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Now that you’ve created a Kafka-specific user, you are ready to download and extract the Kafka binaries.
Step 2 — Downloading and Extracting the Kafka Binaries
Let’s download and extract the Kafka binaries into dedicated folders in our kafka user’s home directory.
To start, create a directory in /home/kafka called Downloads to store your downloads:
mkdir ~/Downloads
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Use curl to download the Kafka binaries:
curl "https://downloads.apache.org/kafka/2.6.3/kafka_2.13-2.6.3.tgz" -o ~/Downloads/kafka.tgz
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Create a directory called kafka and change to this directory. This will be the base directory of the Kafka installation:
mkdir ~/kafka && cd ~/kafka
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Extract the archive you downloaded using the tar command:
tar -xvzf ~/Downloads/kafka.tgz --strip 1
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We specify the --strip 1 flag to ensure that the archive’s contents are extracted in ~/kafka/ itself and not in another directory (such as ~/kafka/kafka_2.13-2.6.3/) inside of it.
Now that we’ve downloaded and extracted the binaries successfully, we can start configuring our Kafka server.
Step 3 — Configuring the Kafka Server
Kafka’s default behavior will not allow you to delete a topic. A Kafka topic is the category, group, or feed name to which messages can be published. To modify this, you must edit the configuration file.
Kafka’s configuration options are specified in server.properties. Open this file with nano or your favorite editor:
nano ~/kafka/config/server.properties
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First, add a setting that will allow us to delete Kafka topics. Add the following to the bottom of the file:
~/kafka/config/server.properties
delete.topic.enable = true
Second, change the directory where the Kafka logs are stored by modifying the logs.dir property:
~/kafka/config/server.properties
log.dirs=/home/kafka/logs
Save and close the file. Now that you’ve configured Kafka, your next step is to create systemd unit files for running and enabling the Kafka server on startup.
Step 4 — Creating Systemd Unit Files and Starting the Kafka Server
In this section, you will create systemd unit files for the Kafka service. This will help you perform common service actions such as starting, stopping, and restarting Kafka in a manner consistent with other Linux services.
Zookeeper is a service that Kafka uses to manage its cluster state and configurations. It is used in many distributed systems. If you would like to know more about it, visit the official Zookeeper docs.
Create the unit file for zookeeper:
sudo nano /etc/systemd/system/zookeeper.service
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Enter the following unit definition into the file:
/etc/systemd/system/zookeeper.service
[Unit]
Requires=network.target remote-fs.target
After=network.target remote-fs.target
[Service]
Type=simple
User=kafka
ExecStart=/home/kafka/kafka/bin/zookeeper-server-start.sh /home/kafka/kafka/config/zookeeper.properties
ExecStop=/home/kafka/kafka/bin/zookeeper-server-stop.sh
Restart=on-abnormal
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WantedBy=multi-user.target
The [Unit] section specifies that Zookeeper requires networking and the filesystem to be ready before it can start.
The [Service] section specifies that systemd should use the zookeeper-server-start.sh and zookeeper-server-stop.sh shell files for starting and stopping the service. It also specifies that Zookeeper should be restarted if it exits abnormally.
After adding this content, save and close the file.
Next, create the systemd service file for kafka:
sudo nano /etc/systemd/system/kafka.service
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Enter the following unit definition into the file:
/etc/systemd/system/kafka.service
[Unit]
Requires=zookeeper.service
After=zookeeper.service
[Service]
Type=simple
User=kafka
ExecStart=/bin/sh -c '/home/kafka/kafka/bin/kafka-server-start.sh /home/kafka/kafka/config/server.properties > /home/kafka/kafka/kafka.log 2>&1'
ExecStop=/home/kafka/kafka/bin/kafka-server-stop.sh
Restart=on-abnormal
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WantedBy=multi-user.target
The [Unit] section specifies that this unit file depends on zookeeper.service. This will ensure that zookeeper gets started automatically when the kafka service starts.
The [Service] section specifies that systemd should use the kafka-server-start.sh and kafka-server-stop.sh shell files for starting and stopping the service. It also specifies that Kafka should be restarted if it exits abnormally.
Now that you have defined the units, start Kafka with the following command:
sudo systemctl start kafka
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To ensure that the server has started successfully, check the journal logs for the kafka unit:
sudo systemctl status kafka
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You will receive output like this:
Output● kafka.service
Loaded: loaded (/etc/systemd/system/kafka.service; disabled; vendor preset: enabled)
Active: active (running) since Wed 2021-02-10 00:09:38 UTC; 1min 58s ago
Main PID: 55828 (sh)
Tasks: 67 (limit: 4683)
Memory: 315.8M
CGroup: /system.slice/kafka.service
├─55828 /bin/sh -c /home/kafka/kafka/bin/kafka-server-start.sh /home/kafka/kafka/config/server.properties > /home/kafka/kafka/kafka.log 2>&1
└─55829 java -Xmx1G -Xms1G -server -XX:+UseG1GC -XX:MaxGCPauseMillis=20 -XX:InitiatingHeapOccupancyPercent=35 -XX:+ExplicitGCInvokesConcurrent -XX:MaxInlineLevel=15 -Djava.awt.headless=true -Xlog:gc*:file=>
Feb 10 00:09:38 cart-67461-1 systemd[1]: Started kafka.service.
You now have a Kafka server listening on port 9092.
You have started the kafka service. But if you rebooted your server, Kafka would not restart automatically. To enable the kafka service on server boot, run the following commands:
sudo systemctl enable zookeeper
sudo systemctl enable kafka
