Firecracker vs Cloud Hypervisor

Firecracker and Cloud Hypervisor are open-source virtual machine monitors (VMMs) written in Rust that use the Kernel-based Virtual Machine (KVM) to create lightweight VMs for cloud workloads. They both emphasize minimal device models, small attack surfaces, and fast boot times, but differ in scope, features, and supported guest operating systems. Firecracker, developed by Amazon Web Services, is optimized for high-density serverless and container workloads, supporting Linux and OSv guests with minimal device models and built-in rate limiting. It is known for its simplicity and low memory overhead, making it suitable for environments prioritizing density and simplicity over feature breadth. Cloud Hypervisor, under the Linux Foundation's governance, supports a wider range of features, including Windows guests, live migration, GPU passthrough, and CPU/memory hotplug, making it suitable for feature-rich cloud workloads. Both VMMs are supported by Kata Containers, which bridges them to the Container Runtime Interface for Kubernetes integration. Northflank leverages Cloud Hypervisor as its primary VMM for microVM-backed sandboxes, using Firecracker for specific workloads, demonstrating the flexibility of both technologies in various deployment scenarios.