Fly.io Introduces Writeable Root Filesystems as Alternative to Ephemeral Sandboxes

Summary

Fly.io argues that traditional read-only sandboxes for code execution are obsolete and introduces a new approach using writeable root filesystems. The article explains how their system allows persistent, isolated environments that don't need to be destroyed after each use, enabling better performance and more natural development workflows. They discuss the technical implementation, security considerations, and benefits over traditional ephemeral sandboxes.