Amazon ECS Managed Instances adds cross-instance and Spot consolidation

Amazon ECS Managed Instances now supports cross-instance consolidation, which evaluates tasks across multiple underutilized instances to pack them onto fewer instances, improving resource utilization and lowering costs. This feature evaluates task placement across the fleet rather than per instance, enabling more efficient repacking when a capacity provider uses a narrow range of instance types. Previously, optimization operated on each instance in isolation, limiting consolidation opportunities in such configurations.

Spot consolidation extends this capability to Spot Instances by first verifying replacement capacity is available before consolidating underutilized Spot Instances. Both optimizations apply to On-Demand and Spot workloads, with the system continuously monitoring the fleet to reclaim idle capacity and consolidate tasks with minimal disruption. The process includes graceful start-before-stop task replacement to maintain workload availability during consolidation.

In testing with a capacity provider configured for c9g instances, cross-instance consolidation reduced a fleet from 19 instances to 13 while raising CPU utilization from 42% to 91% and memory utilization from 41% to 88%. The fleet transitioned from a mix of 4xlarge, 8xlarge, 12xlarge, and 24xlarge instances to primarily 4xlarge and 8xlarge instances, demonstrating significant efficiency gains.

Cross-instance and Spot consolidation are available at no additional cost in all AWS Regions and apply automatically to existing and new ECS Managed Instances capacity providers. The enhancements aim to deliver deeper cost optimization for both On-Demand and Spot workloads without requiring manual intervention or configuration changes.