Sylve

Modern, open-source management platform for FreeBSD managing Virtual Machines (Bhyve), Jails, and ZFS storage.

Version Tags

Both tags ship Sylve's prebuilt native-FreeBSD binary from a GitHub release; they differ only in which release they track.

Tag	Description	Best For
latest	The latest tagged release (AlchemillaHQ/Sylve).	Most deployments.
nightly	The rolling tip release, tracking upstream master.	Early access to unreleased fixes.

Why Sylve is different

Sylve manages the host's Bhyve VMs, jails, and ZFS -- from inside its own jail. That needs host-level access a normal container doesn't get: kernel modules the jail can't load, a devfs ruleset exposing /dev/pf, /dev/vmm, and /dev/cam/ctl, ZFS delegation (zfs jail), and allow.vmm. ocijail can't express all of that through annotations, so this image ships:

• a one-time host-setup script (kernel modules, devfs ruleset, ZFS dataset), and
• an OCI createRuntime hook that delegates the ZFS pool and sets jail params on every start.

There is no AppJail deployment -- the mechanism relies on Podman's OCI hooks, which AppJail doesn't have. Deploy it with Podman Compose as below.

Requirements

• FreeBSD 15+ with podman, ocijail, and podman-compose
• A ZFS pool (host-setup creates a sylve dataset inside it)
• root

Deploy

1. Prepare the host (one time)

Generate the setup script, review it, then run it. It confirms each step (-y to skip the prompts) and skips anything already configured.

podman run --rm ghcr.io/daemonless/sylve:latest host-setup > sylve-setup.sh
less sylve-setup.sh          # review exactly what it will change
sh sylve-setup.sh            # or: sh sylve-setup.sh -y

It loads the kernel modules, adds a devfs ruleset, creates the ZFS dataset, and installs the OCI hook. If it reports that kern.racct needs a reboot, reboot before continuing (Sylve requires it).

2. Create the deployment files

init writes compose.yaml and .env into the current directory (it refuses to overwrite existing files without --force):

podman run --rm -v "$PWD:/out" ghcr.io/daemonless/sylve:latest init

Edit .env:

Variable	Set to
SYLVE_HOSTNAME	The hostname/FQDN you reach Sylve at -- must match (node-identity check).
SYLVE_DATA_LOCATION	Host path for Sylve's data.
SYLVE_DATASET	ZFS dataset to delegate (the one host-setup created).

3. Start

mkdir -p "$SYLVE_DATA_LOCATION"   # FreeBSD won't auto-create a bind-mount source
podman compose up -d

Sylve is then reachable at https://<SYLVE_HOSTNAME>:8181.

Notes

Hostname must match. Sylve's EnsureCorrectHost check compares its configured hostname against what you reach it at; a mismatch fails requests with selected_node_not_found.

Never bind-mount /dev (-v /dev:/dev). A nullfs /dev makes Bhyve guest-memory mmap fail with ENXIO (Unable to setup memory (6)) -- VM creation succeeds but the guest never boots. The hook mounts a real devfs via the ruleset; don't override it.

Undo. sh sylve-setup.sh --undo removes Sylve's hook and devfs ruleset. It never touches your ZFS dataset (it prints the zfs destroy command if you want it gone).

---

Registry	ghcr.io/daemonless/sylve
Upstream	https://github.com/AlchemillaHQ/Sylve
Website	https://sylve.io