Xenomorph: Live-Replace a Linux Rootfs

Xenomorph replaces a running Linux root filesystem with a new in-memory rootfs using pivot_root(2). Feed it an OCI image, a tarball, or a Containerfile and it builds a new root, gracefully stops services, and pivots — all without a reboot.

Written in Zig, it integrates with systemd’s rescue.target and supports headless operation via Tailscale for remote SSH access. The old root is preserved at /mnt/oldroot for inspection and recovery.