Chapter 3. Kafka Bridge configuration

Procedure

1. Edit the application.properties file provided with the Kafka Bridge installation archive.

   Use the properties file to specify Kafka and HTTP-related properties.

   1. Configure standard Kafka-related properties, including properties specific to the Kafka consumers and producers.

      Use:

      • kafka.bootstrap.servers to define the host/port connections to the Kafka cluster
      • kafka.producer.acks to provide acknowledgments to the HTTP client

      • kafka.consumer.auto.offset.reset to determine how to manage reset of the offset in Kafka

        For more information on configuration of Kafka properties, see the Apache Kafka website

   2. Configure HTTP-related properties to enable HTTP access to the Kafka cluster.

      For example:

      bridge.id=my-bridge
      http.host=0.0.0.0
      http.port=8080 

      1

      
      http.cors.enabled=true 

      2

      
      http.cors.allowedOrigins=https://strimzi.io 

      3

      
      http.cors.allowedMethods=GET,POST,PUT,DELETE,OPTIONS,PATCH 

      4

      1

      The default HTTP configuration for the Kafka Bridge to listen on port 8080.

      2

      Set to true to enable CORS.

      3

      Comma-separated list of allowed CORS origins. You can use a URL or a Java regular expression.

      4

      Comma-separated list of allowed HTTP methods for CORS.

2. Save the configuration file.

Procedure

1. Set the bridge.metrics configuration to jmxPrometheusExporter.

   Configuration for enabling metrics

   bridge.metrics=jmxPrometheusExporter

   Optionally, you can add a custom Prometheus JMX Exporter configuration using the bridge.metrics.exporter.config.path property. If not configured, a default embedded configuration file is used.

2. Run the Kafka Bridge run script.

   Running the Kafka Bridge

   ./bin/kafka_bridge_run.sh --config-file=<path>/application.properties

   With metrics enabled, you can scrape metrics in Prometheus format from the /metrics endpoint of the Kafka Bridge.

Procedure

1. Set the bridge.metrics configuration to strimziMetricsReporter.

   Configuration for enabling metrics

   bridge.metrics=strimziMetricsReporter

   Optionally, you can configure a comma-separated list of regular expressions to filter exposed metrics using the kafka.prometheus.metrics.reporter.allowlist property. If not configured, a default set of metrics is exposed.

   When needed, it is possible to configure the allowlist per client type. For example, by using the kafka.admin prefix and setting kafka.admin.prometheus.metrics.reporter.allowlist=, all admin client metrics are excluded.

   You can add any plugin configuration to the Kafka Bridge properties file using kafka., kafka.admin., kafka.producer., and kafka.consumer. prefixes. In the event that the same property is configured with multiple prefixes, the most specific prefix takes precedence. For example, kafka.producer.prometheus.metrics.reporter.allowlist takes precedence over kafka.prometheus.metrics.reporter.allowlist.

2. Run the Kafka Bridge run script.

   Running the Kafka Bridge

   ./bin/kafka_bridge_run.sh --config-file=<path>/application.properties

   With metrics enabled, you can scrape metrics in Prometheus format from the /metrics endpoint of the Kafka Bridge.

Procedure

1. Edit the application.properties file provided with the Kafka Bridge installation archive.

   Use the bridge.tracing property to enable the tracing you want to use.

   Example configuration to enable OpenTelemetry

   bridge.tracing=opentelemetry 

   1

   1

   The property for enabling OpenTelemetry is uncommented by removing the # at the beginning of the line.

   With tracing enabled, you initialize tracing when you run the Kafka Bridge script.

2. Save the configuration file.

3. Set the environment variables for tracing.

   Environment variables for OpenTelemetry

   OTEL_SERVICE_NAME=my-tracing-service 

   1

   
   OTEL_EXPORTER_OTLP_ENDPOINT=http://localhost:4317 

   2

   1

   The name of the OpenTelemetry tracer service.

   2

   The gRPC-based OTLP endpoint that listens for spans on port 4317.

4. Run the Kafka Bridge script with the property enabled for tracing.

   Running the Kafka Bridge with OpenTelemetry enabled

   ./bin/kafka_bridge_run.sh --config-file=<path>/application.properties

   The internal consumers and producers of the Kafka Bridge are now enabled for tracing.