...

Please keep the discussion on the mailing list rather than commenting on the wiki (wiki discussions get unwieldy fast).

Motivation

KIP-13 introduced client quotas in Kafka 0.9.0.0. Rate limits on producers and consumers are enforced to prevent clients saturating the network or monopolizing broker resources. The current implementation allocates quotas to client-ids. This works well in single user clusters or clusters that use PLAINTEXT where all users have the same identity. But since client-id is unauthenticated and can be set to any value by the client, multi-tenant secure installations require quotas to be enforced for authenticated principals to guarantee fair allocation of resources and prevent denial-of-service.

...