Imaginary Machines: A Serverless Model for Cloud Applications

TL;DR

This paper addresses the mismatch between VM-based cloud apps and serverless elasticity by proposing Imaginary Machines, a serverless model that preserves the network-of-hosts programming interface while enabling automated, on-demand resource orchestration through application-level signals. The approach envisions extending Boxer-style overlays to run unmodified applications on public FaaS platforms (e.g., AWS Lambda), observing resource allocation and release signals to transparently manage host functions without explicit runtime orchestration. It discusses feasibility and latency considerations (e.g., host instantiation times on Lambda) and outlines a concrete realization path, signaling potential gains in resource utilization and operational simplicity. If successful, Imaginary Machines could let ordinary cloud applications enjoy serverless benefits without rearchitecting to a FaaS-specific model, reducing management overhead and improving utilization.

Abstract

Serverless Function-as-a-Service (FaaS) platforms provide applications with resources that are highly elastic, quick to instantiate, accounted at fine granularity, and without the need for explicit runtime resource orchestration. This combination of the core properties underpins the success and popularity of the serverless FaaS paradigm. However, these benefits are not available to most cloud applications because they are designed for networked virtual machines/containers environments. Since such cloud applications cannot take advantage of the highly elastic resources of serverless and require run-time orchestration systems to operate, they suffer from lower resource utilization, additional management complexity, and costs relative to their FaaS serverless counterparts. We propose Imaginary Machines, a new serverless model for cloud applications. This model (1.) exposes the highly elastic resources of serverless platforms as the traditional network-of-hosts model that cloud applications expect, and (2.) it eliminates the need for explicit run-time orchestration by transparently managing application resources based on signals generated during cloud application executions. With the Imaginary Machines model, unmodified cloud applications become serverless applications. While still based on the network-of-host model, they benefit from the highly elastic resources and do not require runtime orchestration, just like their specialized serverless FaaS counterparts, promising increased resource utilization while reducing management costs.