AWS autoscaling documentation change
Summary
Added 'Reservations then balanced' strategy documentation prioritizing capacity reservations over AZ balancing
Security assessment
Documents cost-optimization strategy for reserved instances without security controls or vulnerability mitigations
Diff
diff --git a/autoscaling/ec2/userguide/ec2-auto-scaling-availability-zone-balanced.md b/autoscaling/ec2/userguide/ec2-auto-scaling-availability-zone-balanced.md index cd17bcca1..e4241569d 100644 --- a//autoscaling/ec2/userguide/ec2-auto-scaling-availability-zone-balanced.md +++ b//autoscaling/ec2/userguide/ec2-auto-scaling-availability-zone-balanced.md @@ -20,0 +21,11 @@ Auto Scaling maintains an equal number of instances across enabled Availability +**Reservations then balanced** + + +Auto Scaling first launches instances into the Capacity Reservations associated with the group, prioritizing reservation use over even distribution across the group's enabled Availability Zones. After all available reservations are filled, Auto Scaling distributes any remaining capacity evenly across the enabled Availability Zones. Use this strategy for cost-sensitive workloads that use Capacity Reservations, such as GPU, high performance computing (HPC), or machine learning workloads. With this strategy, maximizing reservation utilization takes priority over even Availability Zone distribution. + +You specify the reservations to prioritize by providing a Capacity Reservation group or an individual Capacity Reservation ID. You can specify the target in your launch template or on the Auto Scaling group using [CapacityReservationTarget](https://docs.aws.amazon.com/autoscaling/ec2/APIReference/API_CapacityReservationTarget.html). To prioritize more than one reservation, you can create a Capacity Reservation resource group. This strategy supports On-Demand Capacity Reservations, Capacity Blocks, and interruptible Capacity Reservations. + +###### Note + +During scale in, Auto Scaling removes instances that are not in a reservation first, to preserve reservation utilization. If further scale in is required, Auto Scaling then removes reserved instances, starting with the Availability Zone that has the most reserved instances. + @@ -22,0 +34,2 @@ The Availability Zone distribution strategy selection is in the **Network** sect +When you choose the **Reservations then balanced** strategy, you must also specify the Capacity Reservations to prioritize, either by Capacity Reservation group or by individual Capacity Reservation ID. +