Tutorial: Use EC2 Fleet with On-Demand as the primary capacity

This tutorial uses a fictitious company called ABC Online to illustrate the process of requesting an EC2 Fleet with On-Demand as the primary capacity, and Spot capacity if available.

Objective

ABC Online, a restaurant delivery company, wants to be able to provision Amazon EC2 capacity across EC2 instance types and purchasing options to achieve their desired scale, performance, and cost.

Plan

ABC Online requires a fixed capacity to operate during peak periods, but would like to benefit from increased capacity at a lower price. ABC Online determines the following requirements for their EC2 Fleet:

• On-Demand Instance capacity – ABC Online requires 15 On-Demand Instances to ensure that they can accommodate traffic at peak periods.

• Spot Instance capacity – ABC Online would like to improve performance, but at a lower price, by provisioning 5 Spot Instances.

Verify permissions

Before creating an EC2 Fleet, ABC Online verifies that it has an IAM role with the required permissions. For more information, see EC2 Fleet prerequisites.

Create a launch template

Next, ABC Online creates a launch template. The launch template ID is used in the following step. For more information, see Create a launch template.

Create the EC2 Fleet

ABC Online creates a file, config.json, with the following configuration for its EC2 Fleet. In the following example, replace the resource identifiers with your own resource identifiers.

{
    "LaunchTemplateConfigs": [
        {
            "LaunchTemplateSpecification": {
                "LaunchTemplateId": "lt-07b3bc7625cdab851",
                "Version": "2"
            }

        }
    ],
    "TargetCapacitySpecification": {
        "TotalTargetCapacity": 20,
        "OnDemandTargetCapacity":15,
        "DefaultTargetCapacityType": "spot"
    }
}

ABC Online creates the EC2 Fleet using the following create-fleet command.

aws ec2 create-fleet \
    --cli-input-json file://config.json

For more information, see Create an EC2 Fleet.

Fulfillment

The allocation strategy determines that the On-Demand capacity is always fulfilled, while the balance of the target capacity is fulfilled as Spot if there is capacity and availability.