DAGit: A Platform For Enabling Serverless Applications.

Serverless computing is rapidly gaining popularity for provisioning composable, auto-scalable and cost-effective applications. An important mechanism for deploying serverless applications is specification of function workflows (via DAGs). The end-to-end life cycle of this process being DAG specification, DAG orchestration, execution of DAG components and persistent storage of application outputs. To the best of our knowledge, an open-source platform that offers functionality along all these components does not exist. Towards this, our primary contribution is DAGit, an open-source solution for serverless applications-as-a-service. The main features of DAGit are interfaces and specifications to register serverless functions, applications (via DAGs) and triggers to instantiate the serverless applications. DAGit provides a rich set of DAG primitives to enable a varied set of applications and also implements a scalable orchestrator for application execution. As part of this work, we present the architecture and design details of DAGit, and demonstrate its feature set via showcasing the specification and execution of a varied set of serverless applications. Further, we also present a performance and resource costs characterization of executing applications on the DAGit platform.