Source manifest: http://milinda.pathirage.org/kappa-architecture.com/
What is Kappa Architecture?
Kappa Architecture is a software architecture pattern. Rather than using a relational DB like SQL or a key-value store like Cassandra, the canonical data store in a Kappa Architecture system is an append-only immutable log. From the log, data is streamed through a computational system and fed into auxiliary stores for serving.
Kappa Architecture is a simplification of Lambda Architecture. A Kappa Architecture system is like a Lambda Architecture system with the batch processing system removed. To replace batch processing, data is simply fed through the streaming system quickly.
Kappa Architecture revolutionizes database migrations and reorganizations: just delete your serving layer database and populate a new copy from the canonical store! Since there is no batch processing layer, only one set of code needs to be maintained.