Amazon ARC introduces automated Lambda event source mapping for failover

Amazon has announced a new feature for its Application Recovery Controller (ARC) Region Switch that simplifies the failover process for multi-Region applications. This new addition, known as the Lambda event source mapping execution block, streamlines the coordination of event streams during failovers.

For businesses utilizing event-driven architectures, Lambda functions paired with event source mappings are essential for processing data from sources like Kinesis, DynamoDB Streams, MSK, or SQS. In scenarios where active-passive workloads are deployed, Lambda functions may exist in multiple Regions, but only one Region processes events at a time. Traditionally, switching these event source mappings during a failover has been a manual and potentially error-prone task.

The new Lambda event source mapping execution block automates this process by enabling or disabling mappings in the appropriate Regions during a failover. Customers can configure two types of execution blocks: a disable block to halt event processing in the Region that is being deactivated, and an enable block to initiate processing in the Region that is activating. In cases of unplanned failovers, where the deactivating Region may be compromised, the disable block can be bypassed by executing the plan in “ungraceful” mode.

Additionally, the feature supports cross-account operations, allowing a single failover plan to manage event stream transitions across multiple accounts. This enhancement is available in all commercial Regions where ARC Region Switch operates. For more information on how to implement this feature, refer to the Lambda event source mapping execution block documentation.