Immutable Software Deploys Using ZFS Jails on FreeBSD

FreeBSD’s native support for ZFS snapshots and jails provides a powerful foundation for immutable deployments. By creating a new jail from a ZFS snapshot for every release, we get instant roll‑backs, zero‑downtime upgrades, and a clean, reproducible environment. This article walks through the (very opinionated) flow that we use. From jails setup through running Caddy as a health‑checked reverse proxy in front of the jails.