EC2 Fleet and Spot Fleet request types - Amazon Elastic Compute Cloud
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EC2 Fleet and Spot Fleet request types

The request type for an EC2 Fleet or Spot Fleet determines whether the request is synchronous or asynchronous, and whether it is a one-time request for the desired target capacity or an ongoing effort to maintain the capacity over time. When configuring your fleet, you must specify the request type.

Both EC2 Fleet and Spot Fleet offer two request types: request and maintain. In addition, EC2 Fleet offers a third request type called instant.

Fleet request types
instant (EC2 Fleet only)

If you configure the request type as instant, EC2 Fleet places a synchronous one-time request for your desired capacity. In the API response, it returns the instances that launched and provides errors for those instances that could not be launched. For more information, see Configure an EC2 Fleet of type instant.

request

If you configure the request type as request, the fleet places an asynchronous one-time request for your desired capacity. If capacity diminishes due to Spot interruptions, the fleet does not attempt to replenish Spot Instances, nor does it submit requests in alternative Spot capacity pools if capacity is unavailable. When creating a Spot Fleet of type request using the console, clear the Maintain target capacity checkbox.

maintain (default)

If you configure the request type as maintain, the fleet places an asynchronous request for your desired capacity, and maintains it by automatically replenishing any interrupted Spot Instances. When creating a Spot Fleet of type maintain using the console, select the Maintain target capacity checkbox