Approach

SCAR provides a command-line interface to create a Lambda function to execute a container out of a Docker image stored in Docker Hub. Each invocation of the Lambda function will result in the execution of such a container (optionally executing a shell-script inside the container for further versatility).

The following underlying technologies are employed:

• udocker: A tool to execute Docker containers in user space.
  • The Fakechroot execution mode of udocker is employed, since Docker containers cannot be natively run on AWS Lambda. Isolation is provided by the boundary of the Lambda function itself.
• AWS Lambda: A serverless compute service that runs Lambda functions in response to events.

SCAR can optionally define a trigger so that the Lambda function is executed whenever a file is uploaded to an Amazon S3 bucket. This file is automatically made available to the underlying Docker container run on AWS Lambda so that an user-provided shell-script can process the file. See the Event-Driven File-Processing Programming Model for more details.