Cloud Hypervisor feels need for speedy updates in 21.0 release

Cloud Hypervisor 21.0

A good month after getting a new home, virtual machine monitor Cloud Hypervisor is celebrating its first major release under the auspices of the Linux Foundation. 

Version 21 of the project is mainly about speeding up live upgrades. Users can now pass a --local option to the ch-remote send-migration command to pass file descriptors over the UNIX socket. This means the tool doesn’t have to copy the guest RAM anymore when upgrading a VMM, which the project claims lead to a speedup “in the order of 50ms vs 3s.”

Live migration should also lead to less problems starting with the release, since the process is now supported within firmware and shouldn’t lead to deadlocks when triggered during kernel boot anymore.

Other notable bug fixes mitigate issues around the OpenAPI CAML file, help to make direct=on work with hypervisor-fw boots, and validate the virtio-net descriptor chain so that users know when it wasnt set up properly.

Cloud Hypervisor is a Rust project which is based on the rust-vmm crates and runs on kernel-based virtual machines and Microsoft hypervisors. First released in 2019 by Intel, it promises to provide features to securely run modern cloud workloads on x86-64 and AArch64 architectures. 

Thanks to this focus, the project is a bit more lightweight than your typical hypervisor, as it allows its developers to get rid of drivers for physical devices and focus on input from paravirtualized (virtio) devices instead. Currently supported guest operating systems are 64-bit Linux and Windows 10/Windows Server 2019. 

Supported by companies such as Alibaba, Arm, and Microsoft, Cloud Hypervisor became part of the Linux Foundation in December 2021, looking to receive support in “accelerating development and adoption” of the project. Other projects currently hosted by the foundation include open source staples such as JavaScript runtime Node.js, container orchestrator Kubernetes, and continuous integration project Jenkins.