Streams Replication Manager Driver
The Streams Replication Manager Driver is responsible for executing the configured replication work between Kafka clusters. This includes data replication, consumer group offset replication, and heartbeating.
The Streams Replication Manager Driver role (SRM Driver) is built on top of the Kafka Connect framework and utilizes a group of connectors to execute replication. While Kafka Connect is bound to a single Kafka cluster by design, the SRM Driver must connect to multiple Kafka clusters. The SRM Driver achieves this by wrapping multiple Connect workers in a single driver process. Specifically, for each possible replication between the configured clusters, the SRM Driver spins up a separate Connect worker. The Connect workers join a Connect group which is dedicated to a single replication in the target Kafka cluster. Afterwards, each Connect group creates a single MirrorSourceConnector, a single MirrorCheckpointConnector and a single MirrorHeartbeatConnector. These Connectors and the task instances they generate are responsible for different aspects of the replication work.
When SRM Driver High Availability is in use, the Connect workers that are tied to a specific replication, but are running in different SRM Driver processes, coordinate through the Connect group protocol and balance the load.