>Cloud computing services that run customer code in short-lived processes are often called "serverless". But under the hood, virtual machines (VMs) are usually launched to run that isolated code on demand. The boot times for these VMs can be slow. This is the cause of noticeable start-up latency in a serverless platform like Amazon Web Services (AWS) Lambda. To address the start-up latency, AWS developed Firecracker, a lightweight virtual machine monitor (VMM), which it recently released as open-source software. Firecracker emulates a minimal device model to launch Linux guest VMs more quickly.
>Firecracker began as a fork of Google's crosvm from ChromeOS. It runs Linux guest VMs using the Kernel-based Virtual Machine (KVM) API and emulates a minimal set of devices. Currently, it supports only Intel processors, but AMD and Arm are planned to follow. In contrast to the QEMU code base of well over one million lines of C, which supports much more than just qemu-kvm, Firecracker is around 50 thousand lines of Rust.