EC2Spot

Inspired by prior art lox/ec2spot. EC2Spot takes a list of instance types and dumps out spot pricing over the last 7 days include min, max, and avg spot pricing. It also provides the instance_type, full on-demand price, savings percentage, and an estimate of interrupts from EC2 Spot Advisor.

This gem requires an authenticated AWS client. You can use whatever auth you want, but the easiest way to do that is to set environment variables for AWS_ACCESS_KEY_ID, AWS_SECRET_ACCESS_KEY, and AWS_REGION.

If you're making new IAM keys you can pretty tightly scope them with the following policy:

{
  "Version": "2012-10-17",
  "Statement": [
    {
      "Effect": "Allow",
      "Action": [
        "ec2:DescribeInstanceTypeOfferings",
        "ec2:DescribeSpotPriceHistory",
        "pricing:DescribeServices",
        "pricing:ListPriceLists",
        "pricing:GetAttributeValues",
        "pricing:GetPriceListFileUrl",
        "pricing:GetProducts",
        "ec2:DescribeInstanceTypes"
      ],
      "Resource": "*"
    }
  ]
}

export AWS_ACCESS_KEY_ID="AKIA0123456789012345"
export AWS_SECRET_ACCESS_KEY="someiamsecretaccesskey"
export AWS_REGION="us-east-2"

You can unset them to cleanup

unset AWS_ACCESS_KEY_ID
unset AWS_SECRET_ACCESS_KEY
unset AWS_REGION

The class is a singleton so you can grab the instance with #instance or if you have updated your config and want to refresh the AWS SDK clients #instance!.

require "ec2spot"

instances = [
  "m4.large",
  "m5.large"
]

EC2Spot.instance.prices(*instances)
# =>
# [{:instance=>"m4.large", :min=>0.0478, :max=>0.057, :avg=>0.05334242424242424, :full=>0.1, :savings=>0.46657575757575764, :interrupts=>"<5%"},
# {:instance=>"m5.large", :min=>0.031, :max=>0.0338, :avg=>0.03227777777777777, :full=>0.096, :savings=>0.6637731481481481, :interrupts=>"10-15%"}]