Use Amazon EC2 Spot best practices for Amazon Batch

Choose the SPOT_CAPACITY_OPTIMIZED allocation strategy – Amazon Batch chooses Amazon EC2 instances from the deepest Amazon EC2 Spot capacity pools. If you’re concerned about interruptions, this is a suitable choice. For more information, see Instance type allocation strategies for Amazon Batch.

Diversify instance types – To diversify your instance types, consider compatible sizes and families, then let Amazon Batch choose based on price or availability. For example, consider c5.24xlarge as an alternative to c5.12xlarge or c5a, c5n, c5d, m5, and m5d families. For more information, see Be flexible about instance types and Availability Zones.

Reduce job runtime or checkpoint – We advise against running jobs that take an hour or more when using Amazon EC2 Spot instances to avoid interruptions. If you divide or checkpoint your jobs into smaller parts that consist of 30 minutes or less, you can significantly reduce the possibility of interruptions.

Use automated retries – To avoid disruptions to Amazon Batch jobs, set automated retries for jobs. Batch jobs can be disrupted for any of the following reasons: a non-zero exit code is returned, a service error occurs, or an instance reclamation occurs. You can set up to 10 automated retries. For a start, we recommend that you set at least 1-3 automated retries. For information about tracking Amazon EC2 Spot interruptions, see Spot Interruption Dashboard.

For Amazon Batch, if you set the retry parameter, the job is placed at the front of the job queue. That is, the job is given priority. When you create the job definition or you submit the job in the Amazon CLI, you can configure a retry strategy. For more information, see submit-job.

$ aws batch submit-job --job-name MyJob \
    --job-queue MyJQ \
    --job-definition MyJD \
    --retry-strategy attempts=2

Use custom retries – You can configure a job retry strategy to a specific application exit code or instance reclamation. In the following example, if the host causes the failure, the job can be retried up to five times. However, if the job fails for a different reason, the job exits and the status is set to FAILED.

"retryStrategy": {
    "attempts": 5,
    "evaluateOnExit":
    [{
        "onStatusReason" :"Host EC2*",
        "action": "RETRY"
    },{
      "onReason" : "*",
        "action": "EXIT"
    }]
}

Use the Spot Interruption Dashboard – You can use the Spot Interruption Dashboard to track Spot interruptions. The application provides metrics on Amazon EC2 Spot instances that are reclaimed and which Availability Zones that Spot instances are in. For more information, see Spot Interruption Dashboard