Installing kafka and running kafka

Create a topic

create topic 'my-first-topic'

list topics

send messages to the topic

Using the Offset Explorer

Courtesy of Ralf Ueberfuhr

The Offset Explorer (formerly: Kafka Tool) is a GUI application for managing Kafka. We can download and install it quickly. Then, we create a connection and specify the host and port of the Kafka broker

Open

You will see

Open

Yu can use this to administer the channels (kafka calls them logs)

Using UI for Apache Kafka (Kafka UI) - my preferred option

Courtesy of Ralf Ueberfuhr

The UI for Apache Kafka (Kafka UI) is a web UI, implemented with Spring Boot and React, and provided as a Docker container for a simple installation with the following command:

We can then open the UI in the browser using http://localhost:8080 and define a cluster, as this picture shows:

Because the Kafka broker runs in a different container than the Kafka UI’s backend, it will not have access to localhost:9092. We could instead address the host system using host.docker.internal:9092, but this is just the bootstrapping URL.

Unfortunately, Kafka itself will return a response that leads to a redirection to localhost:9092 again, which won’t work. If we do not want to configure Kafka (because this would break with the other clients then), we need to create a port forwarding from the Kafka UI’s container port 9092 to the host systems port 9092. The following sketch illustrates the connections (Courtesy of Ralf Ueberfuhr):

We can set up this container-internal port forwarding, e.g. using socat. We have to install it within the container (Alpine Linux), so we need to connect to the container’s bash with root permissions. So we need these commands, beginning within the host system’s command line:

Connect to the container's bash (find out the name with 'docker ps')

Courtesy of Ralf Ueberfuhr

Now, we are connected to the container's bash.

Let's install 'socat'

Use socat to create the port forwarding

kafka_producer app cheat sheet

Commands