What guarantees does Kafka provide within the CAP theorem?

Within the framework of the CAP theorem (Consistency, Availability, Partition tolerance), Apache Kafka provides the following guarantees:

• Partition tolerance — Kafka is designed as a distributed system and guarantees operation during network partitions.

• Availability — Kafka ensures high data availability through partition replication and automatic leader failover.

• Consistency — Kafka provides consistency within partitions, meaning the order of messages within a partition is strictly maintained. However, global consistency across partitions is not guaranteed.

Thus, Kafka balances between availability and consistency, ensuring strong consistency within partitions and high availability and partition tolerance. This aligns with the CP (Consistency + Partition tolerance) model at the partition level, with some trade-offs to ensure high performance and scalability.