AWS EC2 Spot Price Terraform module

An easy way to get the best Spot price to control costs.

data "aws_ami" "ubuntu" {
  most_recent = true

  filter {
    name   = "name"
    values = ["ubuntu/images/hvm-ssd/ubuntu-focal-20.04-amd64-server-*"]
  }

  filter {
    name   = "virtualization-type"
    values = ["hvm"]
  }

  owners = ["099720109477"] # Canonical
}

data "aws_availability_zones" "available" {
  state = "available"
}

locals {
  instance_types_list = ["t3a.xlarge"]
}

module "ec2_spot_price" {
  source                        = "fivexl/ec2-spot-price/aws"
  version                       = "2.0.0"
  instance_types_list           = local.instance_types_list
  availability_zones_names_list = data.aws_availability_zones.available.names
}

resource "aws_spot_instance_request" "spot" {
  ami           = data.aws_ami.ubuntu.id
  spot_price    = module.ec2_spot_price.spot_price_current_max
  instance_type = local.instance_type
}

Requirements

Name	Version
terraform	>= 0.13
aws	>= 3.13.0

Inputs

Name	Description	Type	Default	Required
instance_types_list	List of instance types. If not default will overwrite instance_types_weighted_map.	list(string)	[]	no
instance_types_weighted_map	Map of instance_type and their weighted_capacity. Conflict with instance_types_list	list(object({ instance_type = string, weighted_capacity = string}))	[{ instance_type = "t3.micro", weighted_capacity = "1" }]	no
instance_weight_default	Default number of capacity units for all instance types.	number	1	no
availability_zones_names_list	The list with AZs names	list(string)		yes
product_description_list	The product description list for the Spot price (Linux/UNIX, Red Hat Enterprise Linux , SUSE Linux , Windows , Linux/UNIX (Amazon VPC) , Red Hat Enterprise Linux (Amazon VPC) , SUSE Linux (Amazon VPC) , Windows (Amazon VPC)).	list(string)	"Linux/UNIX"	no
custom_price_modifier	Modifier for getting custom prices. Must be between 1 and 2. Values greater than 1.7 will often not make sense. Because it will be equal or greater than on-demand price.	number	1.05	no
normalization_modifier	Modifier for price normalization (rounded up / ceil). Helps to avoid small price fluctuations. Must be 10, 100, 1000 or 10000.	number	1000	no

Outputs

Name	Description
spot_price_current_max	Maximum current Spot Price, which allows to run all Instance Types in all AZ. Maximum stability.
spot_price_current_max_mod	Modified maximum current Spot Price. (multiplied by the custom_price_modifier). Additional stability on rare runs of terraform apply.
spot_price_current_min	Minimum current Spot Price, which allows to run at least one Instance Type in at least one AZ. Lowest price.
spot_price_current_min_mod	Modified minimum current Spot Price. (multiplied by the custom_price_modifier). Additional stability on rare runs of terraform apply.
spot_price_current_optimal	Optimal current Spot Price, which allows to run at least one Instance Type in all AZ. Balance between stability and costs.
spot_price_current_optimal_mod	Modified optimal current Spot Price. (multiplied by the custom_price_modifier). Additional stability on rare runs of terraform apply.

License

Apache 2 Licensed. See LICENSE for full details.

Notes

Amazon EC2 Pricing

• On-Demand
• Spot Instances
• Savings Plans
• Reserved Instances
• Dedicated Hosts

AWS EC2 Auto Scaling

• Instance weighting

How to determine how much Spot Instance costs - Spot Instance data feed

Spot Instance data feed

data "aws_canonical_user_id" "current" {}

module "s3_spot_datafeed" {
  source  = "terraform-aws-modules/s3-bucket/aws"
  version = "1.17.0"

  bucket = "spot-data-feed-example"
  acl    = null
  grant = [{
    type        = "CanonicalUser"
    permissions = ["FULL_CONTROL"]
    id          = data.aws_canonical_user_id.current.id
    }, {
    type        = "CanonicalUser"
    permissions = ["FULL_CONTROL"]
    id          = "c4c1ede66af53448b93c283ce9448c4ba468c9432aa01d700d3878632f77d2d0"
    # Ref. https://github.com/terraform-providers/terraform-provider-aws/issues/12512
    # Ref. https://docs.aws.amazon.com/AmazonCloudFront/latest/DeveloperGuide/AccessLogs.html
  }]

  versioning = {
    enabled = true
  }

  server_side_encryption_configuration = {
    rule = {
      apply_server_side_encryption_by_default = {
        sse_algorithm = "AES256"
      }
    }
  }

  // S3 bucket-level Public Access Block configuration
  block_public_acls       = true
  block_public_policy     = true
  ignore_public_acls      = true
  restrict_public_buckets = true
}

# There is only a single subscription allowed per account.
resource "aws_spot_datafeed_subscription" "default" {
  bucket = module.s3_spot_datafeed.this_s3_bucket_id
  prefix = "spot-data-feed" #required
}