Support Auto Scaling groups Attribute-Based Instance Type Selection for EC2 Auto Scaling (aws_autoscaling_group) and EC2 Fleet (aws_spot_fleet_request)

[jnerin]

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Description

AWS improved the way you select instance types for autoscaling or fleets, now instead of passing a list of possible instance types you can set some attributes (like min and max VCpuCount, and min and max MemoryMiB among others) and let the ABS (yeah, they named it like that, from attribute-based instance type selection) choose the instances.

New or Affected Resource(s)

• aws_autoscaling_group
• aws_spot_fleet_request

Potential Terraform Configuration

resource "aws_autoscaling_group" "example" {
  availability_zones = ["us-east-1a"]
  desired_capacity   = 1
  max_size           = 1
  min_size           = 1

  mixed_instances_policy {
    launch_template {
      launch_template_specification {
        launch_template_id = aws_launch_template.example.id
      }

      override {
        instance_requirements {
          vcpu_count {
            min = "2"
            max = "4"
          }
          memory_mib {
            min = "2048"
          }
        }
      }
    }
  }
}

References

• Announcement https://aws.amazon.com/about-aws/whats-new/2021/10/amazon-ec2-instance-auto-scaling-ec2-spot-fleet/
• Blog post https://aws.amazon.com/blogs/aws/new-attribute-based-instance-type-selection-for-ec2-auto-scaling-and-ec2-fleet/
• User guide https://docs.aws.amazon.com/autoscaling/ec2/userguide/create-asg-instance-type-requirements.html
• API docs https://docs.aws.amazon.com/autoscaling/ec2/APIReference/API_InstanceRequirements.html
• Go SDK https://github.com/aws/aws-sdk-go/releases/tag/v1.41.12

Requires

Requires AWS SDK v1.41.12

[wosiu]

+1000, some questions though:
Currently if I don't specify spot_max_price, it is calculated automatically based on the "on-demand" price (and I hope it gets the cheapest instance type I set in mixed_instances_policy->launch_template->override multiple times). How it's going to be calculated if ABS is provided and no specific instance type to refer to?
Or maybe the default behaviour I described is handled on AWS side and not tf provider?

[gudlyf]

+1 for sure on this. We're anxious to move to this model, but really cannot until Terraform supports it.

There are also "Additional Instance Attributes" that will need to be supported as part of this, which could be quite extensive (i.e., CPU manufacturers, Memory per vCPU, Instance generation, Instance storage, etc.). This will likely make the implementation a bit complex.

[mwos-sl]

Are there any plans or ETA for this one?

[ahujarajesh]

Is there any plan to add this support?

[AdamTylerLynch]

This change impacts the following resources (3):

1. aws_autoscaling_group
2. aws_ec2_fleet
3. aws_spot_fleet_request

https://aws.amazon.com/about-aws/whats-new/2021/10/amazon-ec2-instance-auto-scaling-ec2-spot-fleet/

Plus aws_launch_template - see #24543.

[github-actions]

This functionality has been released in v4.16.0 of the Terraform AWS Provider. Please see the Terraform documentation on provider versioning or reach out if you need any assistance upgrading.

For further feature requests or bug reports with this functionality, please create a new GitHub issue following the template. Thank you!

[github-actions]

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