What is Envelope?
Brokers use this to forward client requests to the KRaft controller while preserving the original client's identity for authorization. When a broker proxies a CreateTopics request to the controller, the ACL check uses the actual client's principal, not the broker's.
| Version | Kafka | Changes |
|---|---|---|
| EnvelopeRequest | ||
| v0 | 2.8 | + RequestData bytes+ RequestPrincipal bytes+ ClientHostAddress bytes~ Flexible encoding enabled FLEXIBLE |
| EnvelopeResponse | ||
| v0 | 2.8 | + ResponseData bytes+ ErrorCode int16~ Flexible encoding enabled FLEXIBLE |