Platforms and Limits

Barn is built for local development and testing. This page helps you choose a host and understand what each guest type supports.

Version

These docs cover Barn 0.9.0. Install the release, check barn version, and read the release notes for changes. The Linux image catalog updates independently with barn update.

Linux guests

Barn builds for all four targets. The principal native test paths are macOS arm64 and Linux amd64; Intel macOS and Linux arm64 have narrower validation coverage. Linux also requires usable /dev/kvm and NetworkManager or systemd-networkd. barn doctor checks the host; barn setup --dry-run shows the dependency and network changes for your machine.

The embedded catalog contains nine image families and 41 artifacts: Ubuntu 22.04/24.04/26.04, Debian 12/13, Rocky Linux 8/9/10, and CentOS 7. See image versions and compatibility for the exact matrix.

• Linux labs support 1–20 nodes in one private /24, with one deployment per user.
• Foreign architectures use QEMU TCG emulation. Rocky Linux 8 arm64 also uses TCG on Apple Silicon because its 64 KiB kernel is incompatible with HVF.
• CentOS 7 is a deprecated compatibility image limited to native Linux/amd64.
• vm_shares works on Linux hosts. For Linux guests on macOS, use SSH file transfer: the guarded QEMU 9p sharing path cannot start those nodes.

macOS guests

barn mac requires Apple Silicon, macOS 27 or later, a logged-in desktop session, and the Barn Mac native component. Guests run macOS 27. QEMU and the Linux host network are not required. See the Mac guide.

• The first machine needs about 65 GiB free for the restore image, installed base, and initial writes. Downloads are resumable; a local IPSW also works.
• At most two macOS VMs can run at once per Mac, including other tools and macOS installation. You may keep more stopped machines.
• Each machine has a separate private subnet, SSH keys, login password, and disk. Shared folders use VirtioFS, independently of Linux vm_shares.
• Clipboard sharing handles plain text, not images or files.
• USB passthrough, snapshots, and suspend/resume are not supported. Apple Account sign-in inside a VM may not work reliably.

Use barn mac doctor for Mac-specific diagnostics and barn mac ls to inspect machines. barn status, destroy, and purge operate on the Linux lab only.

Data and lifecycle

Keep important files backed up outside the lab. Linux root and non-persistent data disks are replaced by recreate and removed by destroy. Persistent disks survive ordinary destruction, but damaged or unrecognized data filesystems can still be reset during guest recovery. Storage and access describes these rules in detail.

Mac recreate replaces the guest disk with a fresh clone. Mac destroy removes that machine’s disk, credentials, and settings; shared host folders remain unchanged.

For operational help, see troubleshooting. For the source and release validation process, see contributing and releases.