Important

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Security Overview

The Schema Registry currently supports all Kafka security features, including: communication and authentication with a secure Kafka cluster over SSL; authentication with ZooKeeper over SASL; authentication with Kafka over SASL; and end-user REST API calls over HTTPS.

For more details, check the configuration options.

Kafka Store

The Schema Registry uses Kafka to persist schemas, and all Kafka security features are supported by the Schema Registry.

ZooKeeper

The Schema Registry supports both unauthenticated and SASL authentication to Zookeeper.

Setting up ZooKeeper SASL authentication for the Schema Registry is similar to Kafka’s setup. Namely, create a keytab for the Schema Registry, create a JAAS configuration file, and set the appropriate JAAS Java properties.

In addition to the keytab and JAAS setup, be aware of the zookeeper.set.acl setting. This setting, when set to true, enables ZooKeeper ACLs, which limits access to znodes.

Important: if zookeeper.set.acl is set to true, the Schema Registry’s service name must be the same as Kafka’s, which is kafka by default. Otherwise, the Schema Registry will fail to create the _schemas topic, which will cause a leader not available error in the DEBUG log. The Schema Registry log will show org.apache.kafka.common.errors.TimeoutException: Timeout expired while fetching topic metadata when Kafka does not set ZooKeeper ACLs but the Schema Registry does. The Schema Registry’s service name can be set either with kafkastore.sasl.kerberos.service.name or in the JAAS file.

If the Schema Registry has a different service name than Kafka, at this time zookeeper.set.acl must be set to false in both the Schema Registry and Kafka.