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Kafka storage Configuration

Many aspects of the monitor extension are configurable. The configuration files are stored in the data directory under the monitoring directory:

<data_directory>
    monitoring/
        monitor.properties

In particular:

  • monitor.properties - Can be extended to set the connection details to Apache Kafka.

Monitor Storage

How request data is persisted is configurable via the storage property defined in the monitor.properties file. The following values are supported for the storage property:

  • memory - Request data is to be persisted in memory alone.
  • hibernate - Request data is to be persisted in a relational database via Hibernate.
  • kafka - Request data is to be persisted in Apache Kafka.

The default value is memory, in order to use Apache Kafka the storage configuration needs to be switched to kafka.

In addition you can set the topic name with the kafka.topic property. The default value is geoserver-monitor.

You can set all the Kafka properties for a kafka producer by prefixing it with the kafka keyword e.g. set the acks to 1 with kafka.acks=1. For further details on the Kafka producer properties see the Kafka documentation.

The following is an example of the monitor.properties file configured to use Apache Kafka:

storage=kafka
... other properties ...
kafka.bootstrap.servers=localhost:9092
kafka.topic=monitor
kafka.acks=1
kafka.retries=3
kafka.batch.size=65536
kafka.linger.ms=200
kafka.compression.type=snappy
kafka.schema.registry.url=http://localhost:8081

In order to use Confluent Cloud you need to configure these properties:

storage=kafka
... other properties ...
kafka.bootstrap.servers=pkc-def12.europe-west.gcp.confluent.cloud:9092
kafka.topic=monitor
kafka.security.protocol=SASL_SSL
kafka.sasl.mechanism=PLAIN
kafka.sasl.jaas.config=org.apache.kafka.common.security.plain.PlainLoginModule required username='KAFKA_API_KEY' password='KAFKA_SECRET';
kafka.schema.registry.url=https://psrc-abc12.europe-west.gcp.confluent.cloud
kafka.schema.registry.basic.auth.credentials.source=USER_INFO
kafka.schema.registry.basic.auth.user.info=SR_API_KEY:SR_API_SECRET

kafka.acks=1
kafka.retries=0
kafka.batch.size=65536
kafka.linger.ms=200
kafka.compression.type=snappy

It might be a good idea to set the kafka.linger.ms to avoid too many requests to the Kafka broker and get the benefits from batching and compression. One request can cause multiple messages to be sent to Kafka as a load of multiple tiles may does. Also the compressions should be quite effective as the messages repeat some data. Make sure to also set the kafka.compression.type.