kafka-synth-client

packaged by Chainguard

Chainguard Container for kafka-synth-client

Synthetic Kafka Client for Monitoring E2E Latencies

Chainguard Containers are regularly-updated, secure-by-default container images.

Download this Container Image

For those with access, this container image is available on cgr.dev:

docker pull cgr.dev/ORGANIZATION/kafka-synth-client:latest

Be sure to replace the ORGANIZATION placeholder with the name used for your organization's private repository within the Chainguard Registry.

Compatibility Notes

The Chainguard kafka-synth-client image is a replacement for the upstream JVM-mode ghcr.io/spoud/kafka-synth-client image. Kafka Synth Client is a synthetic Kafka producer and consumer, built with Java 21 and Quarkus and licensed under the MIT License, that sends probe messages through every broker, consumes them back, and exposes the measured end-to-end latencies as Prometheus metrics alongside a built-in web UI. This image tracks upstream v1.11.7.

Like the upstream image, the entrypoint is /opt/jboss/container/java/run/run-java.sh, which launches /deployments/quarkus-run.jar using the JAVA_APP_JAR, JAVA_OPTS_APPEND, and JAVA_MAX_MEM_RATIO environment variables. The image runs as the non-root jboss user (UID 185) with /home/jboss as its home and working directory. Unlike the Red Hat UBI-based upstream image, it runs on Chainguard's OpenJDK 21 runtime and does not include the UBI s2i or Maven tooling.

Getting Started

Start the client against a Kafka broker reachable at kafka:9092:

docker run -d --name synth -p 8081:8081 \
  -e KAFKA_BOOTSTRAP_SERVERS=kafka:9092 \
  -e SYNTH_CLIENT_TOPIC=synth.e2e.messages \
  -e SYNTH_CLIENT_TOPIC_REPLICATION_FACTOR=1 \
  cgr.dev/ORGANIZATION/kafka-synth-client:latest

Check health and scrape the latency metrics:

curl -fsS http://localhost:8081/q/health
curl -fsS http://localhost:8081/q/metrics | grep synth_client

The web UI is served at http://localhost:8081/.

Configuration

• The application listens on port 8081 by default (quarkus.http.port). Override it with QUARKUS_HTTP_PORT, for example -e QUARKUS_HTTP_PORT=8080.
• Kafka client properties are set with KAFKA_* environment variables (for example KAFKA_BOOTSTRAP_SERVERS, KAFKA_SECURITY_PROTOCOL, KAFKA_SASL_MECHANISM, KAFKA_SASL_JAAS_CONFIG), and client settings with SYNTH_CLIENT_* variables (for example SYNTH_CLIENT_RACK, SYNTH_CLIENT_TOPIC, SYNTH_CLIENT_AUTO_CREATE_TOPIC).
• JVM options can be added through JAVA_OPTS_APPEND; heap sizing follows JAVA_MAX_MEM_RATIO (default 50).
• Any mounted directory the application writes to must be writable by UID 185.

Documentation and Resources

• Kafka Synth Client GitHub
• Kafka Synth Client documentation

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This software listing is packaged by Chainguard. The trademarks set forth in this offering are owned by their respective companies, and use of them does not imply any affiliation, sponsorship, or endorsement by such companies.