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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, many organizations also use it for log aggregation because it offers persistent storage for published messages.
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 configure Apache Kafka 2.8.2 on Ubuntu 20.04.
To follow along, you will need:
sudo
privileges. You can set this up by following our Initial Server Setup guide if you do not have a non-root user set up. Installations with less than 4GB of RAM may cause the Kafka service to fail.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. You will create a dedicated kafka
user in this step.
Log in to your server as your non-root sudo
user, then create a user called kafka
:
- sudo adduser kafka
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
Your kafka
user is now ready. Log in to the kafka
account using su
:
- su -l kafka
Now that you’ve created a Kafka-specific user, you are ready to download and extract the Kafka binaries.
In this step, you’ll download and extract the Kafka binaries into dedicated folders in your kafka
user’s home directory.
To start, create a directory in /home/kafka
called Downloads
to store your downloads:
- mkdir ~/Downloads
Use curl
to download the Kafka binaries:
- curl "https://downloads.apache.org/kafka/2.8.2/kafka_2.13-2.8.2.tgz" -o ~/Downloads/kafka.tgz
Create a directory called kafka
and move to this directory. You’ll use this directory as the base directory of the Kafka installation:
- mkdir ~/kafka && cd ~/kafka
Extract the archive you downloaded using the tar
command:
- tar -xvzf ~/Downloads/kafka.tgz --strip 1
You 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_2.13-2.8.2/
) inside of it.
Now that you’ve downloaded and extracted the binaries successfully, you can start configuring your Kafka server.
A Kafka topic is the category, group, or feed name to which messages can be published. However, Kafka’s default behavior will not allow you to delete a topic. To modify this, you must edit the configuration file, which you will do in this step.
Kafka’s configuration options are specified in server.properties
. Open this file with nano
or your favorite editor:
- nano ~/kafka/config/server.properties
First, add a setting that will allow you to delete Kafka topics. Add the following line to the bottom of the file:
delete.topic.enable = true
Second, you’ll change the directory where the Kafka logs are stored by modifying the log.dirs
property. Find the log.dirs
property and replace the existing route with the highlighted route:
log.dirs=/home/kafka/logs
Save and close the file.
Now that you’ve configured Kafka, you can create systemd
unit files for running and enabling the Kafka server on startup.
systemd
Unit Files and Starting the Kafka ServerIn this section, you will create systemd
unit files for the Kafka service. These files will help you perform common service actions such as starting, stopping, and restarting Kafka in a manner consistent with other Linux services.
Kafka uses Zookeeper to manage its cluster state and configurations. It is used in many distributed systems, and you can read more about the tool in the official Zookeeper docs. You’ll use Zookeper as a service with these unit files.
Create the unit file for zookeeper
:
- sudo nano /etc/systemd/system/zookeeper.service
Enter the following unit definition into the file:
[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
[Install]
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
Enter the following unit definition into the file:
[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
[Install]
WantedBy=multi-user.target
The [Unit]
section specifies that this unit file depends on zookeeper.service
, which 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.
Save and close the file.
Now that you have defined the units, start Kafka with the following command:
- sudo systemctl start kafka
To ensure that the server has started successfully, check the journal logs for the kafka
unit:
- sudo systemctl status kafka
You will receive output like this:
Output● kafka.service
Loaded: loaded (/etc/systemd/system/kafka.service; disabled; vendor preset>
Active: active (running) since Wed 2023-02-01 23:44:12 UTC; 4s ago
Main PID: 17770 (sh)
Tasks: 69 (limit: 4677)
Memory: 321.9M
CGroup: /system.slice/kafka.service
├─17770 /bin/sh -c /home/kafka/kafka/bin/kafka-server-start.sh /ho>
└─17793 java -Xmx1G -Xms1G -server -XX:+UseG1GC -XX:MaxGCPauseMill>
You now have a Kafka server listening on port 9092
, which is the default port the Kafka server uses.
You have started the kafka
service. But if you reboot your server, Kafka will not restart automatically. To enable the kafka
service on server boot, run the following command:
- sudo systemctl enable zookeeper
You’ll receive a response that a symlink was created:
OutputCreated symlink /etc/systemd/system/multi-user.target.wants/zookeeper.service → /etc/systemd/system/zookeeper.service.
Then run this command:
- sudo systemctl enable kafka
You’ll receive a response that a symlink was created:
OutputCreated symlink /etc/systemd/system/multi-user.target.wants/kafka.service → /etc/systemd/system/kafka.service.
In this step, you started and enabled the kafka
and zookeeper
services. In the next step, you will check the Kafka installation.
In this step, you will test your Kafka installation. You will publish and consume a Hello World message to make sure the Kafka server is behaving as expected.
Publishing messages in Kafka requires:
To begin, create a topic named TutorialTopic
:
- ~/kafka/bin/kafka-topics.sh --create --zookeeper localhost:2181 --replication-factor 1 --partitions 1 --topic TutorialTopic
You can create a producer from the command line using the kafka-console-producer.sh
script. It expects the Kafka server’s hostname, a port, and a topic as arguments.
You’ll receive a response that the topic was created:
OutputCreated topic TutorialTopic.
Now publish the string "Hello, World"
to the TutorialTopic
topic:
- echo "Hello, World" | ~/kafka/bin/kafka-console-producer.sh --broker-list localhost:9092 --topic TutorialTopic > /dev/null
Next, create a Kafka consumer using the kafka-console-consumer.sh
script. It expects the ZooKeeper server’s hostname and port, along with a topic name, as arguments. The following command consumes messages from TutorialTopic
. Note the use of the --from-beginning
flag, which allows the consumption of messages that were published before the consumer was started:
- ~/kafka/bin/kafka-console-consumer.sh --bootstrap-server localhost:9092 --topic TutorialTopic --from-beginning
If there are no configuration issues, you will receive a Hello, World
response in your terminal:
OutputHello, World
The script will continue to run, waiting for more messages to publish. To test this, open a new terminal window and log in to your server. Remember to log in as your kafka
user:
- su -l kafka
In this new terminal, start a producer to publish a second message:
- echo "Hello World from Sammy at DigitalOcean!" | ~/kafka/bin/kafka-console-producer.sh --broker-list localhost:9092 --topic TutorialTopic > /dev/null
This message will load in the consumer’s output in your original terminal:
OutputHello, World
Hello World from Sammy at DigitalOcean!
When you are done testing, press CTRL+C
to stop the consumer script in your original terminal.
You have now installed and configured a Kafka server on Ubuntu 20.04. In the next step, you will perform a few quick tasks to harden the security of your Kafka server.
With your installation complete, you can remove the kafka
user’s admin privileges and harden the Kafka server.
Before you do so, log out and log back in as any other non-root sudo
user. If you are still running the same shell session that you started this tutorial with, type exit
.
Remove the kafka
user from the sudo group:
- sudo deluser kafka sudo
To further improve your Kafka server’s security, lock the kafka
user’s password using the passwd
command. This action ensures that nobody can directly log into the server using this account:
- sudo passwd kafka -l
The -l
flag locks the command to change a user’s password (passwd
).
At this point, only root
or a sudo
user can log in as kafka
with the following command:
- sudo su - kafka
In the future, if you want to unlock the ability to change the password, use passwd
with the -u
option:
- sudo passwd kafka -u
You have now successfully restricted the kafka
user’s admin privileges. You are ready to begin using Kafka. You can optionally follow the next step, which will add KafkaT to your system.
KafkaT was developed to improve your ability to view details about your Kafka cluster and to perform certain administrative tasks from the command line. Because it is a Ruby gem, you will need Ruby to use it. You will also need the build-essential
package to build the other gems that KafkaT
depends on.
Install Ruby and the build-essential
package using apt
:
- sudo apt install ruby ruby-dev build-essential
You can now install KafkaT with the gem
command:
- sudo CFLAGS=-Wno-error=format-overflow gem install kafkat
The Wno-error=format-overflow
compilation flag is required to suppress Zookeeper’s warnings and errors during kafkat
’s installation process.
When the installation has finished, you’ll receive a response that it is done:
Output...
Done installing documentation for json, colored, retryable, highline, trollop, zookeeper, zk, kafkat after 3 seconds
8 gems installed
KafkaT uses .kafkatcfg
as the configuration file to determine the installation and log directories of your Kafka server. It should also have an entry pointing KafkaT to your ZooKeeper instance.
Create a new file called .kafkatcfg
:
- nano ~/.kafkatcfg
Add the following lines to specify the required information about your Kafka server and Zookeeper instance:
{
"kafka_path": "~/kafka",
"log_path": "/home/kafka/logs",
"zk_path": "localhost:2181"
}
Save and close the file. You are now ready to use KafkaT.
To view details about all Kafka partitions, try running this command:
- kafkat partitions
You will receive the following output:
Output[DEPRECATION] The trollop gem has been renamed to optimist and will no longer be supported. Please switch to optimist as soon as possible.
/var/lib/gems/2.7.0/gems/json-1.8.6/lib/json/common.rb:155: warning: Using the last argument as keyword parameters is deprecated
...
Topic Partition Leader Replicas ISRs
TutorialTopic 0 0 [0] [0]
__consumer_offsets 0 0 [0] [0]
...
...
The output will include TutorialTopic
and __consumer_offsets
, an internal topic used by Kafka for storing client-related information. You can safely ignore lines starting with __consumer_offsets
.
To learn more about KafkaT, refer to its GitHub repository.
You now have Apache Kafka running securely on your Ubuntu server. You can integrate Kafka into your favorite programming language using Kafka clients.
To learn more about Kafka, you can also consult its documentation.
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Use the following command to create a Topic for Kafka version 3.7.0.
Step 5: Updates
gzip error is occuring because the file is not really a zipped file. I think the problem is the source that expired or deprecated. I have passed this issue by taking the link from https://kafka.apache.org/downloads.
Most of the steps are still valid. Some updates need to be considered.
For example:
For the rest, this quite generic and useful. Thanks.
hello i don’t understand why but i can’t create log for the program :
‘’'sudo systemctl status kafka × kafka.service Loaded: loaded (/etc/systemd/system/kafka.service; enabled; vendor preset: enabled) Active: failed (Result: exit-code) since Wed 2022-08-10 10:29:05 CEST; 2min 21s ago Process: 7519 ExecStart=/bin/sh -c /home/dorianrosse/programs/kafka_2.13-3.2.1/bin/kafka-server-start.sh /home/dorianrosse/programs/kafka_2.13-3.2.1/config/server.properties > /home/dorianrosse/programs/kafka_2.13-3.2.1/kafka.log 2>&1 (code=exited, status=2) Main PID: 7519 (code=exited, status=2) CPU: 3ms
août 10 10:29:05 Ubuntu-ThinkPad-X250 systemd[1]: Started kafka.service. août 10 10:29:05 Ubuntu-ThinkPad-X250 sh[7519]: /bin/sh: 1: cannot create /home/dorianrosse/programs/kafka_2.13-3.2.1/kafka.log: Permission denied août 10 10:29:05 Ubuntu-ThinkPad-X250 systemd[1]: kafka.service: Main process exited, code=exited, status=2/INVALIDARGUMENT août 10 10:29:05 Ubuntu-ThinkPad-X250 systemd[1]: kafka.service: Failed with result ‘exit-code’.
thanks you in advance to help myself fully repair apache kafka,
regards.
Azaretdodo.
Forgot to read the fine-print: “at least 4 gigs of memory is needed or the server won’t start…”
You don’t get a helpful error message, like “not enough memory to start kafka server.” It just fails with status=1.
Kafka version is updated so that url is trying to download a previous version from URL “https://downloads.apache.org/kafka/2.6.3/kafka_2.13-2.6.3.tgz”. that’s why the
curl command
doesn’t work anymore.You can see a list of kafka verions available now from here - https://downloads.apache.org/kafka/
and change the expected version url of yours.
In short you can use this curl command as an alternative of abode istruction to download the latest version for now -
curl "https://downloads.apache.org/kafka/3.2.0/kafka-3.2.0-src.tgz" -o ~/Downloads/kafka.tgz
or
curl "https://dlcdn.apache.org/kafka/3.2.0/kafka-3.2.0-src.tgz" -o ~/Downloads/kafka.tgz
For everyone complaining for gzip error, I think something changed in the kafka website about source download, currently the url is https://dlcdn.apache.org/kafka/3.2.0/kafka-3.2.0-src.tgz ( taken from official download page )
This will solve the gzip error.
Also, in 3.2.0, you cannot start the service if you do not build it with “./gradlew jar -PscalaVersion=2.13.6”
I am getting the same error as MASuwandi
Anyone know a solution?
use the following command to download the correct file curl “https://dlcdn.apache.org/kafka/3.1.0/kafka_2.13-3.1.0.tgz” -o ~/Downloads/kafka.tgz