Kafka

A single-node Kafka broker running in KRaft mode (no ZooKeeper).

Default image: apache/kafka:4.0.0Exposed port: 9092Wait strategy: log message ".*Kafka Server started.*"

Member	Returns
KafkaContainer.start(image?)	Promise<KafkaContainer> — boots the container
.bootstrapServers	A PLAINTEXT://host:port bootstrap-servers address

Example

import { KafkaContainer } from "rightsize/modules";
import { Kafka } from "kafkajs";

await using kafka = await KafkaContainer.start();
const client = new Kafka({ brokers: [kafka.bootstrapServers.replace("PLAINTEXT://", "")] });
const producer = client.producer();
await producer.connect();
await producer.send({ topic: "t", messages: [{ value: "hello" }] });
await producer.disconnect();

Backend notes

• The advertised listener is rewritten to carry the mapped host port, known only once ports are allocated — the same customizeSpec mechanism Redpanda uses, applied here to Kafka's single advertised listener.
• The image's default JVM heap (1GB) is lowered to 256MB by this module. The apache/kafka image's default heap exceeds microsandbox's default microVM RAM and aborts the JVM outright; a single-node KRaft dev broker runs comfortably in 256MB, and the override is harmless on Docker (which isn't memory-constrained the same way here).