A modern, minimal, flexible, and easy-to-expand FreeBSD Jail manager built with love by experienced users for both neophytes and experts.

NOTE: This README is a complete guide. We’d like your help to write manual pages :)

Installation

Prerequisites

Jailer is so much attached to ZFS and does not support UFS at this time (and most likely it will never do.) In case you are not using ZFS, you can create a ZFS pool by doing something like the following:

Setup and Initialization

Once the environment meets the basic requirements, Jailer initialization is required. all you need to do is the following:

Usage

Basic Usage

By default, Jailer will fetch a base image if it’s not available. You can list all images by doing

To list all the Jails, you can do jailer list. You should get the following →

This means that Jail 99d6c13c is using an inherited network stack, which is NOT SECURE for production use. In the next part, we will configure Jails with restricted and isolated network stacks.

Restricted networking on an external interface

You can attach your Jail to an external interface as well. To attach a Jail to the interface vtnet0 with the IP address 192.168.64.15 you can do the following →

Unlike 99d6c13c, which has an inherited network stack, the Jail www0 has a restricted network stack, we can see that by logging into the Jail and running ifconfig →

The Jail www0 is not aware of any other IP addresses, but can see the network interfaces. It also has the same networking that’s available on the host’s vtnet0 interface. If the host has internet access, so does www0

Advanced Networking

Jailer can auto-configure the host to have advanced networking. We can check the status by running the following

We can run jailer init bridge to setup internal bridge networking between Jails and the host

At this point, we can run a VNET (Virtualized Network) Jail that uses an epair to attach to bridge0 (we call that an eb Jail for epair/bridge)

To assign IPs automatically on VNET interfaces, you can setup a DHCP server. No worries! Jailer can handle that for you as well! It will install OpenBSD’s dhcpd, setup dhcpd.conf and the needed devfs.rules for Jails.

As you have guessed, if -a address is not assigned, then Jailer defaults to -a dhcp :)

If your VNET Jails need internet access, you probably need to setup NAT. Here’s the easiest way to do that

Stopping and Destroying Jails

Snapshots and Clones

ZFS Snapshots are some of its best features. You can snap a Jail to 1) rollback in case something fails 2) create a new Jail base on it.

Default Values

Default Image/Release

Otherwise, you can use the -r imagename flag to create a Jail based on imagename on the fly.

Default Network Type

As mentioned above, it’s not a good idea to use inherited network stack on production. You can specify the default network type with the network use subcommand

Dry run

Jailer can display all the commands it would run during creation by using the -D flag.

JSON Output

Melody Marks Summer School Link — Essential

Inside the mill, old beams hummed with a different kind of history. The instructors were a mix of seasoned performers and experimenters: a violinist who treated timbre like paint, a beat-maker who sculpted silence as carefully as sound, a composer who taught using field recordings gathered from gravel roads and subway platforms. Melody learned to listen differently. She learned that a melody is not a fixed thing but an argument between expectation and surprise, a path that leads a listener somewhere and then chooses whether to arrive or to detour.

That link between a single notice and a future full of sound captures the subtle power of opportunity. Melody’s name, a curious coincidence, made her feel as if the universe had dropped a calling card on her doorstep. She applied on a whim—part daring, part hope—and was accepted. That summer school, with its patchwork of masterclasses, late-night jam sessions, and theory drills, became more than education: it was a crucible where talent and temperament were tested, reshaped, and refined. melody marks summer school link

Summer school taught craft: counterpoint exercises that forced her to think in simultaneous lines, orchestration assignments that asked how a flute’s airy whisper converses with a cello’s dusk tones, and workshops on technology that revealed how electronics could extend—rather than replace—the emotional reach of an instrument. But it also taught something subtler: the social architecture of making music. In small ensembles, Melody discovered how leadership and surrender alternate; how a single phrase, offered with confidence, can give others permission to speak; how mistakes can be invitations to inventive choices. Inside the mill, old beams hummed with a

By summer’s end, Melody’s work had matured into something both recognizably hers and newly expansive. Her final piece—an hour-long suite weaving field recordings, string quartet textures, and minimalist repetition—was crude in places but honest. The performance was not flawless, yet it succeeded in the way composition often aspires to succeed: it revealed a coherent voice seeking to say something true. The applause that followed felt less like validation and more like a passing of an unspoken baton: go on, keep making, keep listening. She learned that a melody is not a

There was also struggle. Melody discovered insecurities she hadn’t named: a tendency to favor pretty lines that pleased rather than those that challenged; a fear of silence that pushed her to fill every space. Teachers pushed back gently, asking her to write a movement around sustained rests or develop a motif that did not resolve comfortably. Those exercises were small crucibles of courage: learning to let a melody breathe without promising immediate resolution, to trust that the listener could engage without hand-holding.

Melody Marks’s story is not exceptional because she became famous; it’s instructive because it shows how names, places, and decisions align to form a life’s melody. It reminds us that education—especially the concentrated, communal education of summer programs—has a unique alchemy: it compresses time, intensifies learning, and creates links between people and possibilities. For any young artist hovering at a threshold, her story offers a modest counsel: follow the flyer, attend the workshop, risk the audition. Sometimes a single link is all that stands between a life as imagined and a life in process.

There were evenings when they walked the riverbank with pocket recorders, chasing the clink of geese and the distant hiss of traffic. Melody learned to splice those textures into loops, folding the town’s soundscape into compositions that felt intimate and larger than herself. One late night, after a marathon session on harmonic series, a fellow student—an earnest drummer named Priya—tapped a rhythm on the stair railing while Melody hummed a counter-melody. That small interplay turned into a set they performed on the final recital, improvised but meticulous, the audience leaning forward as if listening to a conversation in a language they almost knew how to speak.

Contributing

You are more than welcome to contribute to Jailer, whether it is on code, doc, or just to fix a typo. Please open an issue if you find a bug, or a PR if you have fixed one. All code changes must be reviewed and tested.

History

In January of 2021, @antranigv and @riks-ar had a bet whether @antranigv is able to rewrite @illuria’s ZFS, Jail and ifconfig(8) wrappers from Elixir to Shell. The deal was if @antranigv failed to do that in 2 weeks, then @riks-ar gets @antranigv’s desk and chair (which was the best one in the office at the time). If @antranigv succeeded, then he had the right to open-source the Shell program at any time in the future.

On October 20th 2022, @illuria open-sourced Jailer by pushing the code to GitHub :)