Cloud Hypervisor vs QEMU

Cloud Hypervisor is a free, open-source virtual machine monitor written in Rust for modern cloud workloads. It runs modern Linux and Windows guests on Linux hosts with x86-64 or AArch64 architectures, using minimal hardware emulation. Operators can manage VM lifecycles through a REST API or command-line interface, with an optional D-Bus API. It supports snapshots, nested virtualization, paravirtualized devices, physical device passthrough, and live migration between hosts without interrupting VMs. Migration data can be encrypted using mutual TLS. The maker says direct kernel boot reaches userspace in less than 100 ms. The project is supported by Kata Containers for running secure containerized workloads and is governed openly as part of the Linux Foundation. It has no commercial plan or usage limits stated. Linux hosts need kernel 4.11 or later for required KVM functionality; kernel 5.6 is recommended for adequate performance. Packages for some popular Linux distributions are available through the Open Build Service. For help, the project points users to GitHub discussions or Slack, with GitHub issues for bug reports and a mailing list for broader discussion.

QEMU is a free, open-source machine emulator and virtualizer. System emulation models an entire machine, including its CPU, memory and devices, so it can run a guest operating system. User-mode emulation runs processes built for one CPU architecture on another. The package also includes qemu-img, a command-line utility for creating, converting and modifying disk images. QEMU can work with KVM, Xen and Hypervisor.Framework so guests can run directly on the host CPU. Supported build platforms include Linux, macOS, FreeBSD, NetBSD, OpenBSD and Windows. Windows support is limited to 64-bit, while macOS requires the newest version currently available; support for the prior version is eventually dropped. For complex networking and storage configurations, the project recommends management tools such as virt-manager. Its security guidance distinguishes virtualization with an accelerator and listed machine type from TCG non-virtualization use, which does not provide guest-isolation or security guarantees. QEMU is released under GNU GPL version 2, with some components under specific licenses.