Amazon EC2 On-Demand or Amazon EC2 Spot
Most AWS Batch customers use Amazon EC2 Spot instances because of the savings over On-Demand instances. However, if your workload runs for multiple hours and can't be interrupted, On-Demand instances might be more suitable for you. You can always try Spot instances first and switch to On-Demand if necessary.
If you have the following requirements and expectations, use Amazon EC2 On-Demand instances:
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The runtime of your jobs is more than an hour, and you can't tolerate interruptions to your workload.
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You have a strict SLO (service-level objective) for your overall workload and can’t increase computational time.
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The instances that you require are more likely to see interruptions.
If you have the following requirements and expectations, use Amazon EC2 Spot instances:
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The runtime for your jobs is typically 30 minutes or less.
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You can tolerate potential interruptions and job rescheduling as a part of your workload. For more information, see Spot Instance advisor
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Long running jobs can be restarted from a checkpoint if interrupted.
You can mix both purchasing models by submitting on Spot instance first and then use On-Demand instance as a
fallback option. For example, submit your jobs on a queue that's connected to compute environments that are running
on Amazon EC2 Spot instances. If a job gets interrupted, catch the event from Amazon EventBridge and correlate it to a Spot instance
reclamation. Then, resubmit the job to an On-Demand queue using an AWS Lambda function or AWS Step Functions. For more
information, see Tutorial: Sending Amazon Simple Notification Service alerts for failed job events, Best practices for handling Amazon EC2 Spot
Instance interruptions
Important
Use different instance types, sizes, and Availability Zones for your On-Demand compute environment to maintain Amazon EC2 Spot instance pool availability and decrease the interruption rate.
