FTL: A New Operating System for Clouds

Introduction to FTL

FTL is a new operating system developed for cloud infrastructure. Its core design principle allows users to construct their own operating system as a library, operating within userspace. This approach facilitates easier feature addition, debugging, and safe OS upgrades, similar to application development.

Enhanced Container Isolation

The FTL kernel provides improved isolation for containers compared to traditional monolithic kernels. It achieves this through a hypervisor-like interface based on lightweight hardware-based isolation, specifically utilizing user mode. This design aims to offer security benefits without requiring bare-metal machines.

Linux Compatibility and Flexibility

FTL maintains compatibility with existing Linux binaries, allowing Linux applications to run on it. For example, a Rust-based HTTP server can operate as a Linux application within FTL. Additionally, it supports running specialized applications, similar to unikernels, without requiring POSIX abstractions.

How FTL Works

Each container in FTL runs its own userspace OS, implemented as a shared library. This library handles most OS concepts, including Linux processes, VFS, and TCP/IP. The FTL kernel offers a minimal interface to enable the implementation of Linux system calls in userspace, functioning similarly to a hypervisor.

Benefits of Userspace OS Design

The userspace OS design allows for extending most Linux kernel features without requiring kernel or eBPF programming. This enables developers to add debugging statements, apply security updates, and introduce new features quickly and safely, treating the OS as a library.