AWS Batch Gains Finer Control Over Instance Allocation
AWS Batch now allows engineers to manually prioritize specific EC2 instance types for their compute environments, optimizing for cost or performance.
Editorial summary and commentary based on the original from AWS What's New. Read the original
What's new
AWS Batch has introduced two new allocation strategies: Best Fit Progressive Ordered (BFPO) for on-demand instances and Spot Capacity Optimized Prioritized (SCOP) for Spot instances. These strategies enable users to define a custom, ordered list of EC2 instance types or families that Batch should attempt to provision. Previously, Batch used its own internal logic for instance selection. With BFPO and SCOP, engineers can explicitly guide Batch to prefer certain instances, giving more granular control over the underlying compute resources.
Why it matters
This update addresses a common challenge in managing large-scale, cost-sensitive, or performance-critical batch workloads. While AWS Batch is excellent for abstracting away infrastructure, there are scenarios where the default instance allocation might not be optimal. For example, a specific workload might perform significantly better on a particular instance family due to CPU architecture or memory configuration. With BFPO, you can ensure your preferred, high-performance instances are tried first for on-demand jobs, potentially reducing overall job execution time and cost by avoiding less efficient alternatives.
For Spot instances, SCOP is particularly impactful. Engineers often have a good understanding of which Spot instance types are generally available or offer the best price-performance for their region and workload. By providing a prioritized list, you can direct Batch to attempt provisioning these known-good Spot instances first, potentially improving job startup times and reducing interruptions compared to relying solely on AWS's capacity-optimized defaults. This feature empowers engineers to leverage their operational knowledge to fine-tune resource provisioning, leading to more predictable performance and potentially lower costs. It shifts some of the instance selection intelligence from AWS's black box into the user's hands, which is a welcome addition for advanced use cases.
How to use it
When creating or updating a compute environment, specify BEST_FIT_PROGRESSIVE_ORDERED or SPOT_CAPACITY_OPTIMIZED_PRIORITIZED and provide your ordered list of instance types via the API or console.
Source (AWS What's New): AWS Batch now supports customer-ordered instance allocation strategies