Bsdkrun CLI

bsdkrun CLI

bsdkrun runs lightweight microVMs (FreeBSD / NetBSD / Linux OCI images) on macOS (Hypervisor.framework) and Linux (KVM), built on libkrun. It's Docker-like: run → ps → exec/shell → stop → start → rm, plus machine snapshots (snapshot/branch/restore), reusable flavors (commit), persistent volumes, port forwards, an in-guest agent (for exec/ssh/tailscale), and optional global networks with internal DNS.

State lives under <state>/ ($XDG_STATE_HOME/bsdkrun or ~/.local/state/bsdkrun); downloads cache under $BSDKRUN_CACHE (default ~/.cache/bsdkrun).

For the full flag list of every command, read references/cli-reference.md.

Command map

Run a guest:

• bsdkrun linux <IMAGE> [-- CMD...] — boot an OCI image (Docker Hub / any registry).
• bsdkrun freebsd [-- CMD...] — FreeBSD (EFI boot on macOS, PVH on Linux/amd64).
• bsdkrun netbsd [-- CMD...] — NetBSD (direct-kernel boot).
• bsdkrun kernel / bsdkrun firmware — low-level boot from a kernel or UEFI image + disk.

Lifecycle:

• bsdkrun ps [-a] [--json] — list machines (running, or all with -a).
• bsdkrun stop <id> — stop a running machine (BSD guests clean-poweroff first).
• bsdkrun start <id> — restart a stopped machine in place (same id/disk, resumes its data).
• bsdkrun update <id> [--cpus N] [--mem M] — change recorded vCPU/RAM (applies on next start).
• bsdkrun rm [-f] <id>... — remove machine(s) and their state (-f stops first).

Interact:

• bsdkrun exec [-t] [-e K=V]... <id> <cmd>... — run a command in a guest (via its agent).
• bsdkrun cp [-r] <SRC> <DST> — copy files host<->guest, docker cp-style (ID:PATH, - = stdio).
• bsdkrun cache save <id>:<path> --key K [-c gzip|zstd|estargz|none] — archive a guest dir.
• bsdkrun cache restore <id>[:<path>] --key K [--restore-keys PREFIX...] — put it back (a miss exits 0).
• bsdkrun cache ls / bsdkrun cache rm <key>... | --all — list and remove entries.
• bsdkrun doctor [--json] — check the host can run machines; exits 1 on any failure.
• bsdkrun shell <id> — attach an interactive console to a detached machine.
• bsdkrun logs [-f] [--boot] <id> — show the console log (--boot = bsdkrun's own boot log).

AI coding agents (sandboxed, one microVM each):

• bsdkrun claude — Claude Code in a sandbox that shares the current directory; also codex, gemini, opencode, crush, copilot, kilo, qwen.
• bsdkrun ai agents [--json] — the agents, and whether each one's image is built.
• bsdkrun ai ls [--json] — sandboxes, grouped by project.
• bsdkrun ai start <agent> [--workspace PATH] [--repo URL] [--name N] [--project P] [--new] [-d]
• bsdkrun ai stop|rm <agent> — rm also drops the saved login unless --keep-home.
• Per-agent $HOME volume (login persists), ~/.agents/skills shared into every sandbox, host git identity + read-only ~/.ssh injected, and git/Docker/Nix preinstalled. --no-workspace shares nothing; --no-ssh withholds the keys.
• bsdkrun ai resume <machine> [-d] — bring ONE stopped sandbox back (keeps its workspace/name/project) and wait for its guest agent; ai start would boot a second one.
• bsdkrun ai disk [ls --watch [SECS]] — the shared Docker/Nix store disks (one running holder at a time), per-sandbox usage, and host free space. ai disk grow docker --size 200G.
• bsdkrun ai upload [--what skills|ssh|git|workspace] [--agent A] [DIR] — copy local skills / keys / git identity / a project onto a REMOTE engine's sandbox ($HOME and system dirs are refused; .gitignore/.dockerignore respected, --all overrides).
• Paths resolve on the engine's host — for a remote daemon use --repo or ai upload.

CI (tangled spindle workflows in microVMs):

• bsdkrun ci run [names...] — run .tangled/workflows/*.yml locally: one microVM per workflow (nixery.dev image from its dependencies:), clone of HEAD, steps streamed. Flags: --event push|pull_request|manual, -f FILE (explicit file, skips matching), -w DIR, --input k=v, --keep (keep the VM after a failure), --json (spindle LogLine JSON). Runs the HEAD commit, never the dirty tree.
• bsdkrun ci ls [--event E] — workflows and whether each matches that trigger.
• bsdkrun ci serve [--bind H:P] — accept sh.tangled.pipeline records over HTTP and run them (a spindle-compatible runner for a server).
• Every SDK can define workflows in code (workflow("test").on_push("main").step(...)) and .run() them — YAML is generated, never hand-written.

Docker (a Docker engine in a microVM, driven by the host's own docker CLI):

• bsdkrun docker start [--cpus N] [--mem M] [--disk-size 60G] [--mount PATH] — boot (or resume) the engine, serve its API on a host unix socket, and point docker at it via a bsdkrun context. One VM, always named bsdkrun-docker; a second start resumes it.
• bsdkrun docker status [--json] / bsdkrun docker stop / bsdkrun docker rm [-f].
• bsdkrun docker ps [-a] [--json] — containers. bsdkrun docker logs <c> [--tail N].
• bsdkrun docker container <start|stop|restart|kill|pause|unpause|rm> <c>....
• bsdkrun docker disk [--size 100G] — show or grow the image store.
• bsdkrun docker env — the DOCKER_HOST line, for a shell not using the context.
• bsdkrun docker shell — a shell in the engine VM (not in a container).
• Published container ports are mirrored onto the host automatically; $HOME is shared into the VM at the same path so -v $PWD:/app resolves.

Snapshots (a machine's disk state, copy-on-write):

• bsdkrun snapshot <id> [name] [-d DESC] — capture a machine's disk state (BSD guests are powered off first, and left stopped; Linux guests keep running).
• bsdkrun snapshots [machine] [--json] — list snapshots, newest first.
• bsdkrun snapshot rm <name>... — delete snapshots and their data.
• bsdkrun branch <snapshot|machine> [-d] [--name N] [--port H:G] — boot a NEW machine from a snapshot; naming a machine snapshots it first. Prints the new machine's id.
• bsdkrun restore <id> <snapshot> [-f] — put a machine back to a snapshot (-f stops it first; the replaced state is snapshotted first unless --no-backup). Left stopped — start to run it.
• bsdkrun rollback <id> [-f] — restore to the machine's most recent snapshot.

Flavors (reusable environments):

• bsdkrun commit <id> <name> — freeze a machine into a flavor (like docker commit).
• bsdkrun flavors [--json] — list the catalog + your snapshots.
• bsdkrun flavor run [-d] <name> [--port H:G] [-v NAME] — boot a machine from a flavor.
• bsdkrun flavor add --base <ref> [--nix PKG] [--provision CMD]... <name> — define a custom flavor.
• bsdkrun flavor build <name> — pre-build a flavor's provisioned rootfs into the cache.
• bsdkrun flavor rm <name> — remove a snapshot / user flavor.

Global networks (shared subnet + internal DNS — like docker-compose):

• bsdkrun network create <name> — create a network (starts its shared gvproxy).
• bsdkrun network ls [--json] — list networks + member counts.
• bsdkrun network rm [-f] <name>... — delete network(s).
• bsdkrun network connect <machine> <network> — join/switch a machine (applies on next start).
• bsdkrun network disconnect <machine> — detach back to isolated (applies on next start).
• bsdkrun network sync <network> — refresh members' /etc/hosts so peers resolve by name.
• Join at boot with --network <name> [--name <member>] on linux/freebsd/netbsd.

Remote access (in-guest agent actions):

• bsdkrun ssh <id> setup|add-key|status [--user U] [--key K]... — key-based SSH.
• bsdkrun tailscale <id> setup|status|install|start [--authkey K] [--hostname H] — tailscale.
• bsdkrun systemd <id> setup|status|disable — systemd as PID 1 (Linux; boot on -v to persist).
• bsdkrun agent update <id> — refresh a stale baked-in guest agent.

Disks, images, volumes:

• bsdkrun prune [--all] [--volumes] [--only KIND]... [-f] [--dry-run] — reclaim disk: stopped machines, unused images, orphaned rootfs trees. Asks with a summary first; --only orphan is the selection that cannot cost anything. --all adds the OCI layer cache; --volumes adds unused volumes.
• bsdkrun images [--json] — list downloaded images.
• bsdkrun image rm <id>... [-f] — remove dangling images (refused while a machine uses one).
• bsdkrun volume ls | rm <name>... — manage persistent volumes.
• bsdkrun fetch [--os freebsd|netbsd] [--version V] — download + prepare a BSD image.
• bsdkrun versions — list downloadable BSD builds.
• bsdkrun grow --disk <path> --size <8G> — enlarge a disk image (guest expands on next boot).
• bsdkrun probe — check that libkrun links and a VM context can be created.

Common flags on run commands (linux/freebsd/netbsd)

• -d, --detach — run in background, print the id (like docker run -d).
• --name <NAME> — machine name (also its DNS name on a --network).
• --network <NAME> — join a global network.
• --cpus <N> / --mem <MiB> — resources (defaults 1 / 512).
• --port <HOST:GUEST> — forward a host TCP port (repeatable), e.g. --port 2222:22.
• -v, --volume <NAME> — persist the rootfs/disk to a named volume.
• --attach-disk PATH[:ro] — attach an extra raw disk image as virtio-blk (repeatable).
• --no-net — boot with no NIC (disables the agent → no exec/shell).
• --repo <URL> — clone a git repo into the guest and cd into it on shell open.
• Linux only: --mount HOST:GUEST[:ro], --entrypoint, -e K=V, --initramfs, --kernel(-version).
• BSD only: --version, --persist, --disk-size 8G, --verbose.

Key behaviors to remember

• start resumes the machine's own storage (its disk / rootfs), not a fresh base image — snapshot and runtime data survive stop/start.
• stop cleanly powers off BSD guests (shutdown -p now) so their UFS is consistent; it takes a few seconds. Linux writes go straight to the host FS.
• NetBSD name resolution relies on /etc/hosts sync (its resolver rejects the gvproxy DNS's AAAA NXDOMAIN). Joins auto-sync; use network sync to refresh an existing network without restarting members.
• Snapshots of BSD guests power the guest off first for a clean, bootable image.
• Linux storage on macOS is case-sensitive. The first Linux launch automatically creates a sparse APFS store for OCI roots and volumes. Inspect or manage it with bsdkrun store status, init, attach, detach, and rm.
• The desktop app mirrors these: Machines, Images, Volumes, Flavors, and Networks views, plus per-machine edit (CPU/RAM, network) and network member browsing.

Examples

# Ephemeral Alpine, run one command
bsdkrun linux alpine -- echo hi

# Detached Ubuntu with SSH forwarded, then exec into it
id=$(bsdkrun linux -d --name web --port 2222:22 ubuntu:24.04 -- sleep infinity)
bsdkrun exec -t "$id" bash
bsdkrun ssh "$id" setup            # installs your ~/.ssh/id_*.pub

# FreeBSD, persistent, on a named volume
bsdkrun freebsd -d --name bsd -v bsddata --disk-size 8G

# Two machines on one network, reachable by name
bsdkrun network create devnet
bsdkrun linux -d --network devnet --name db  postgres
bsdkrun linux -d --network devnet --name api myapi   # api can `ping db`

# Snapshot a configured machine and reuse it
bsdkrun commit web my-web-env
bsdkrun flavor run -d my-web-env