2025-09-27 –, D2
Current jail managers will take over a minute to deploy thick provisioned jails and can't preserve modifications to thin provisioned jails. ZFS's copy-on-write semantics are an almost perfect match for fast FreeBSD jail provisioning, but the inability to rebase ZFS clones constrains the design of efficient automations. This talk explains how ZFS channel programs can be used by a jail manager (or plain old jail.conf(5)) to make idempotent jail provisioning near instantaneous and non-destructive.
You'll learn:
- What tools can be written with the technology we already have in FreeBSD to improve jail management.
- How to write and debug your own ZFS channel programs.
- Why you should keep the base system, applications, configurations, and persistent data separate.
- Where existing FreeBSD jail managers fell behind Linux containers.
- How to provision jails in under a second.
Target audience: intermediate ZFS skills and at least a beginner's understanding of FreeBSD jails or any other container technology.
