paper

Jitsu: Just-In-Time Summoning of Unikernels

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📜 Abstract

Network latency is a problem for all cloud services. It can be mitigated by moving computation out of remote datacenters by rapidly instantiating local services near the user. This requires an embedded cloud platform on which to deploy multiple applications securely and quickly. We present Jitsu, a new Xen toolstack that satisfies the demands of secure multi-tenant isolation on resource-constrained embedded ARM devices. It does this by using unikernels: lightweight, compact, single address space, memory-safe virtual machines (VMs) written in a high-level language. Using fast shared memory channels, Jitsu provides a directory service that launches unikernels in response to network traffic and masks boot latency. Our evaluation shows Jitsu to be a power-efficient and responsive platform for hosting cloud services in the edge network while preserving the strong isolation guarantees of a type-1 hypervisor.

✨ Summary

  • The paper presents Jitsu, a Xen-based toolstack for launching memory-safe MirageOS unikernels on demand, particularly on resource-constrained ARM devices. Its main mechanisms are optimized VM creation, zero-copy shared-memory communication through Conduits, and Synjitsu, a proxy that transfers TCP state after the target unikernel has booted.
  • The evaluation reports cold-start response times of approximately 300–350 ms on ARM and about 30 ms on x86, while preserving type-1 hypervisor isolation. The implementation also demonstrated substantially lower startup latency than the Docker configuration evaluated by the authors.
  • A documented follow-on research project is Fractal: Automated Application Scaling, which provides extensions and an API over Jitsu for application-controlled replica creation, lifecycle management, failure recovery, and traffic distribution. (arxiv.org)
  • The associated open-source Jitsu implementation continued as a DNS server and VM-management system capable of booting unikernels on demand; its repository documents support for MirageOS and Rumprun and multiple virtualization backends. (github.com)
  • The sources reviewed show clear influence on subsequent unikernel and self-scaling systems research, but they do not provide evidence of a specific commercial or industrial deployment of Jitsu itself. The paper’s bibliographic identity and publication details are corroborated by USENIX and DBLP. (usenix.org)