Amazon Application Recovery Controller (ARC) Region Switch helps customers orchestrate the failover of their multi-Region applications to achieve a bounded recovery time in the event of a Regional impairment. Today, we are announcing the Lambda event source mapping execution block, which automates the coordinated failover of event streams for multi-Region workloads.

Customers running event-driven architectures use Lambda functions with event source mappings to process event streams from Kinesis, DynamoDB Streams, MSK, or SQS. For active-passive workloads, customers may maintain Lambda functions in each Region but process events in only one Region at a time. These event source mappings must be toggled during failover to avoid duplicate processing—a manual, error-prone step. The Lambda event source mapping execution block automates this by enabling or disabling event source mappings in either the activating or deactivating Region. To control duplicate processing, customers can configure two Lambda event source mapping execution blocks in sequence: a disable block to stop event processing in the deactivating Region, and an enable block to start it in the activating Region. The disable block can be overridden by running the plan in “ungraceful” mode for unplanned failovers where the deactivating Region may be impaired. Native cross-account support enables a single plan to handle event stream failover across multiple accounts.

To get started, see the Lambda event source mapping execution block documentation. ARC Region switch is available in all commercial Regions. See ARC Region switch availability