Public clouds provide on-demand computing resources over the Internet. The largest are called hyperscalers.
Almost all hyperscalers, at the notable exception of Microsoft Azure, depend on open-source software to support their platform . Put simply, without open-source software, they wouldn't exist, at least not in their current form.
Isn't there an equivalent to these custom building blocks available for everyone to reuse?
Rust-vmm (or Rust-Virtual Machine Monitor) is an ongoing effort among software and hardware companies, including some hyperscalers, to share more of their codebase. Rust-vmm provides a platform to share reusable virtualization-related code by means of Rust-crates .
As of 2021, this project offers the closest open-source equivalent to the aforementioned custom software used by hyperscalers.
At least three key projects using Linux and KVM are also taking advantage of Rust-vmm :
crosvm (2010 --)
firecracker (2018 --)
Cloud Hypervisor (2019 --)
|Support for non-Unix guests||No||No||Yes|
Until recently, any attempt to create a local-first, free and open-source operating system that could run atop affordable, virtualization-friendly hardware using basic building blocks similar to those used by major public clouds would rightfully be met with skepticism.
Thanks to the rust-vmm umbrella project, assembling such an operating system is now becoming a possibility.
Phyllome OS intends to tap into some modern software- and hardware-related innovations used in the cloud and make them available to a wider audience locally: to bring some of the cloud back home, so to speak.
Nowadays, the majority of the cloud market is captured by Amazon and Microsoft. AWS runs on Xen, and Microsoft on Hyper-V which, incidentally, is very similar to Xen design-wise. Amazon is gradually shifting away from Xen, but it will take a very long time for them to migrate to KVM. Microsoft, at least for now, is sticking with Hyper-V. Oracle Cloud used to be on Xen but is gradually migrating to KVM (Thanks to Pasha Tatashin for the summary). Some references: Google Cloud, Honig and Porter, “7 Ways We Harden Our KVM Hypervisor at Google Cloud.”; Alibaba Cloud, Zhang, “KVM Forum 2017.” AWS, Hamilton, “AWS Nitro System – Perspectives.” In the comment section of his article, James Hamilton, one of the designers of the new AWS Nitro System which powers EC2 instances on AWS, explains : “The Nitro hypervisor is built on a minimized and modified Linux kernel, including the KVM subsystem that is responsible for programming hardware virtualization features of the processor.” ↩︎
Open-source or free software are software that are freely available to the general public to reuse, read and modify. ↩︎
In particular, the Linux operating system and its Kernel-based Virtual Machine (KVM) module are two basic, essential, open-source building blocks upon which these hyperscalers are built. ↩︎
Just as most of today’s computing landscape, a witty reader might add ↩︎
For instance, Google Cloud does not rely on QEMU. In an attempt to reduce the attack surface of the platform, its designers decided to replace QEMU – which by default comes with a vast amount of generic features – with their own specialized user-space emulator, which is rumored to be called Vanadium. According to the Wikipedia article, Vanadium as as physical compound “is a hard, silvery-grey, malleable transition metal [...] rarely found in nature [...] [O]nce isolated artificially, the formation of an oxide layer [...] somewhat stabilizes the free metal against further oxidation.” Vanadium would surely be a fitting name for a user-space emulator... ↩︎
he fact that the hyperscalers’ foundations are closed source has several key consequences which go beyond the issues that Phyllome OS seeks to address. Individuals, private companies, and public entities increasingly rely on public clouds to run their most critical workloads. The core engine that propels those hyperscalers is made of computer code that no external party can audit, which means that the aforementioned critical workloads are ultimately not auditable. In other words, individuals, private companies and public entities are building their own essential digital infrastructures on top of black boxes. ↩︎
Crates are snippets of Rust code which provide certain functions or sets of functions. ↩︎
Hyperscalers tend to rely more on custom-made hardware, which might significantly raise the entry bar for new competitors in the future ↩︎