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Enable OAuth2/OIDC support for Apache Kafka® REST proxy

Secure your Apache Kafka® resources by integrating OAuth 2.0/OpenID Connect (OIDC) with the Karapace REST proxy and enabling REST proxy authorization. This setup ensures that only authorized individuals can manage Apache Kafka resources through both token-based authentication and access control rules.

OAuth2/OIDC token handling

Karapace processes the JSON Web Token (JWT) obtained from the Authorization HTTP header, specifically when employing the Bearer authentication scheme. This allows OAuth2/OIDC credentials to be supplied directly to the REST proxy, which uses the provided token to authorize requests to Apache Kafka. When a Bearer token is presented, Kafka clients configured by Karapace use the SASL OAUTHBEARER mechanism to send the JWT for validation.

Authorization enforcement

In the underlying Aiven for Apache Kafka® service, the default mechanism for authorization, uses the sub claim from the JWT as the username. This username is then verified against the configured Access Control Lists (ACLs) to authorize user operations on Kafka resources.

While the sub claim is the default identifier, this setting is configurable. You can specify a different JWT claim for authentication by adjusting the kafka.sasl_oauthbearer_sub_claim_name parameter. For more information on configuring this, see Enable OAuth2/OIDC via Aiven Console.

To authenticate and authorize a user in Aiven for Apache Kafka, both a service user and an ACL entry describing the permissions are required. The JWT claim value used for authentication must explicitly match the service user in the system. Furthermore, this service user must be associated with an ACL entry that outlines their permissions, ensuring that the identity of the user making the request aligns with both the service user and the ACL entry.

Managing token expiry

With OAuth2/OIDC enabled, Karapace manages Kafka client connections for security and performance. It automatically cleans up idle clients and those with tokens nearing expiration, typically on a 5-minute cycle. This cleanup prevents unauthorized access with expired tokens and clears idle connections.


Before your token expires, remove any linked consumers and producers to avoid security issues and service interruptions. After removal, refresh your OAuth2 JWT tokens and reconnect with the new tokens.

Configure OAuth2/OIDC authentication

To establish OAuth2/OIDC authentication for the Karapace REST proxy, complete the following prerequisites and configuration steps:


Configuration via Aiven Console

  1. In Aiven Console, select your project, and choose your Aiven for Apache Kafka® service.
  2. In the service page, select Service settings from the sidebar.
  3. On the Service settings page, scroll down to the Advanced configuration section, and click Configure.
  4. In the Advanced configuration dialog, select Add configuration options.
  5. Look for kafka_rest_authorization parameter and set it to True.

Configuration via Aiven CLI

To enable REST proxy authorization, use the following command in the Aiven CLI, replacing SERVICE_NAME with your actual service name:

avn service update -c kafka_rest_authorization=true SERVICE_NAME

Disable REST proxy authorization, use:

avn service update -c kafka_rest_authorization=false SERVICE_NAME

Enabling Apache Kafka REST proxy authorization can disrupt access for users if the Kafka access control rules have not been configured properly. For more information, see Enable Apache Kafka® REST proxy authorization.