[KAFKA-16612] Talking to controllers via AdminClient requires reconfiguring controller listener

• Type: Improvement
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Assignee: Unassigned
• Reporter: Gantigmaa Selenge
• Created: 24/Apr/24 11:19
• Updated: 28/Aug/24 14:57

Description

After KIP-919, Kafka controllers register themselves with the active controller once they start up. This registration includes information about the endpoints which the controller listener is configured with. This endpoint is then sent to admin clients (via DescribeClusterResponse) so that clients send requests to the active controller. If the controller listener is configured with "CONTROLLER://0.0.0.0:9093" , this will result in admin clients requests failing (trying to connect to localhost). This was not clearly stated in the KIP or the documentation.

When clients talking to brokers, advertised.listeners is used, however advertised.listener is forbidden for controllers. Should we allow advertised.listeners for controllers so that admin client can use it to talk to controllers, in the same way it uses it to talk to brokers? Or should the endpoints provided in controller.quorum.voters, be returned to admin client?

If the intention is to use the regular "listeners" configuration of controller for clients, this should be clearly documented.

Issue Links

• is caused by: KAFKA-16781 Expose advertised.listeners in controller node