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With Alloy Host

alloy-host is a helper tool for developer workstations. It manages the lifecycle of isolated build environments (VMs and Docker containers) so that alloy-provisioner can run inside them, without touching your host machine.

Use alloy-host when you want to:

  • Keep your host clean and switch between project environments easily.
  • Test a blueprint before publishing to Alloy Hub, without manually setting up a VM.
  • Give teammates a one-command environment setup.

Note

alloy-host is a helper tool. Any Linux VM/ Container you manage yourself (Vagrant, VirtualBox, wsl2, etc.) can run alloy-provisioner natively. alloy-host is not required.

Install alloy-host

brew install alloy-it/tap/alloy-host

# amd64
curl -fsSL https://github.com/alloy-it/alloy-host-releases/releases/download/latest/alloy-host_linux_amd64.tar.gz \
  | tar -xz -C /usr/local/bin alloy-host

# arm64
curl -fsSL https://github.com/alloy-it/alloy-host-releases/releases/download/latest/alloy-host_linux_arm64.tar.gz \
  | tar -xz -C /usr/local/bin alloy-host

Download alloy-host_windows_amd64.zip from alloy-host-releases, extract, and add to your PATH.

Verify:

alloy-host check-health

This confirms alloy-host can find the required backend tools.

Choose a backend

alloy-host supports three backends:

Backend Flag Platforms Notes
VirtualBox + Vagrant --backend vm (default) Windows, macOS, Linux Requires VirtualBox and Vagrant installed
WSL2 --backend wsl2 Windows Fast; requires WSL2 enabled
Docker --backend docker All Requires Docker installed

VirtualBox + Vagrant prerequisites (default backend):

  • macOS / Linux: install VirtualBox and Vagrant
  • Windows: same, or use WSL2 instead
  • Apple Silicon (M1/M2/M3): requires VirtualBox 7.1 or later

Create your first environment

1. Initialize

alloy-host init arm-dev --blueprint community/arm-none-eabi

This creates an arm-dev/ directory with the backend configuration and blueprint reference. The VM does not start yet.

To use a local blueprint instead:

alloy-host init arm-dev --blueprint ./path/to/blueprint

To use WSL2 or Docker:

alloy-host init arm-dev --blueprint community/arm-none-eabi --backend wsl2
alloy-host init arm-dev --blueprint community/arm-none-eabi --backend docker

2. Start and provision

cd arm-dev
alloy-host up

alloy-host starts the backend, installs alloy-provisioner inside the guest, and runs the blueprint. You'll see each task execute in sequence. The first run downloads toolchains; this takes a few minutes.

When you use the WSL2 or Docker backend, alloy-host activates the matching runtime environment tag for alloy-provisioner (wsl2 or docker). This means blueprint tasks that use exclude: [wsl2] or exclude: [docker] are skipped automatically.

Bringing machine up...
Running provisioner...
✔  Update APT cache
✔  Install build tools
✔  Install ARM GCC toolchain
✔  Configure PATH
Provisioning complete.

Running alloy-host up again is safe; completed tasks are skipped.

3. Enter the environment

alloy-host ssh

You're now inside the VM (or WSL2/Docker container). Your host project directory is mounted at /vagrant. Verify the toolchain:

arm-none-eabi-gcc --version
cmake --version
ninja --version

4. Stop when done

alloy-host stop

The environment is suspended with everything intact. Resume later with alloy-host up.

Daily workflow

flowchart LR
    Up[alloy-host up] --> SSH[alloy-host ssh]
    SSH --> Work[work inside env]
    Work --> Stop[alloy-host stop]
alloy-host up        # start the environment
alloy-host ssh       # open a shell inside it
# ... do your work ...
alloy-host stop      # shut it down when done

When inside the environment directory you can omit the name. From anywhere else:

alloy-host ssh arm-dev
alloy-host up stm32-proj

Updating the environment

When your blueprint changes, re-provision the running environment:

alloy-host provision

Only new or changed tasks run. Everything else is skipped.

Managing multiple environments

alloy-host list

Shows all registered environments with status, backend, and blueprint.

Destroying and rebuilding

alloy-host destroy       # delete the VM (project files on host are not affected)
alloy-host up            # reprovisioned from scratch

For a complete clean slate (also wipes the persistent data disk):

alloy-host destroy --all
alloy-host up

Quick reference

Command What it does
alloy-host init <name> --blueprint <bp> Create environment directory
alloy-host up [name] Start or recreate the environment
alloy-host ssh [name] Open a shell inside the environment
alloy-host provision [name] Re-run the blueprint (apply updates)
alloy-host stop [name] Suspend the environment
alloy-host destroy [name] Delete the environment
alloy-host list Show all registered environments
alloy-host validate [name] Validate blueprint syntax
alloy-host resolve [name] Generate alloy.lock.yml from catalog refs
alloy-host check-health Verify alloy-host is correctly installed

Full details: Command Reference

Next steps