The company wants three things: minimize client-to-broker latency within the same Availability Zone, increase available bandwidth, and increase the scaling speed of the MSK cluster. The current brokers are Standard brokers (two per AZ). Clients use default settings, which means they are not explicitly configured for rack awareness or AZ affinity.
A common way to reduce latency in multi-AZ Kafka deployments is to enable rack awareness on clients and brokers so clients prefer brokers in the same “rack,” which can map to an Availability Zone. In Kafka, the client.rack setting allows the client to include rack information so the broker can return metadata that helps the client select replicas that are closest, reducing cross-AZ traffic and improving latency.
To increase bandwidth and improve scaling speed, the most direct approach in the choices is to move from Standard brokers to Express brokers. Express brokers are designed to provide higher throughput and faster scaling characteristics compared to standard broker types. Since the question explicitly calls out increasing available bandwidth and scaling speed, the broker type change is the key lever, and it can be combined with client.rack configuration to minimize cross-AZ latency.
Option C matches these requirements: it replaces Standard brokers with Express brokers (to improve throughput/bandwidth and scaling speed) and sets client.rack to the Availability Zone identifier (az_id) to improve locality and reduce latency between clients and brokers in the same AZ.
Option A is not appropriate because MSK does not use EC2 Auto Scaling predictive scaling in that manner, and Kafka clients/brokers are not “associated” with an EC2 placement group as a primary latency solution in MSK. Placement groups are for EC2 instance placement; MSK broker placement is managed by the service.
Option B introduces a proxy layer and MSK Connect in a way that increases complexity and does not directly guarantee lower latency or higher bandwidth. MSK Connect is for Kafka Connect workloads, not as a general-purpose low-latency routing proxy for Kafka clients. Cruise Control is used for partition rebalancing and cluster optimization, but it does not replace the benefits of higher-throughput broker types and client rack awareness for AZ locality.
Option D increases broker size and introduces PrivateLink endpoints. PrivateLink is about private connectivity from VPCs to services and does not inherently ensure AZ-local broker selection or reduce latency between clients and brokers in the same AZ. Also, resizing to xlarge increases capacity but does not address scaling speed and locality as directly as express brokers plus rack configuration.
Therefore, option C best meets all requirements.
[References:AWS documentation on Amazon MSK broker types, including performance and scaling characteristics of Standard and Express brokers.Apache Kafka concepts and AWS guidance on rack awareness and using client.rack to reduce cross-AZ traffic and latency in multi-AZ Kafka deployments., , , , ]
