Caker is a macOS toolchain for building, running and managing virtual machines with Apple's Virtualization framework, focused on simplicity and developer experience. It runs macOS and Linux guests (and, experimentally, Windows 11) from a single CLI, a background daemon or a native desktop app.
Requirements: macOS 15 or later. macOS guests require Apple Silicon.
Highlights
Create VMs from anywhere
- Cloud images (qcow2/raw), installer ISOs, macOS IPSW restore images, OCI images, Simple Streams and existing templates
- A built-in image catalog: pick an image by short id with
--alias (for example --alias macos15 or --alias ubuntu2604) and list the available ids with cakectl aliases
- Import existing VMs from Multipass or VMware
- Duplicate, rename, push/pull to registries and keep reusable templates
Unattended OS installation ("PackerLite")
- With
--autoinstall, Caker drives the first-boot setup for you: macOS Setup Assistant from an IPSW, or a Linux installer from an ISO (Fedora, CentOS, RHEL, openSUSE, Debian, Alpine, Ubuntu)
- Native implementation of a Packer-style
boot_command, with OCR-based <locate>/<click> steps, no external binary or plugin
- Bundled templates for macOS 12 to 27, plus your own with
--template and --var key=value
- Record a template by hand with
caked record, then replay it
- Re-run provisioning later with
provision <vm>, locally or through cakectl, with a live VNC view and an optional debug video of the run
- Windows 11 for ARM can be installed unattended too (see the provisioning guide)
Compose: multi-VM environments
- Describe a group of related VMs in a
compose.yml (a subset of the Docker Compose format) with depends_on ordering, ports, volumes, networks and cloud-init extensions (packages, write_files, post_commands, ...)
cakectl compose up | down | ps | rm | ls | edit, plus a Compose editor in Caker.app- Built-in DNS so services reach each other by name (
<service>.<project>.compose.internal, and <vm>.compose.internal for every running VM), with a configurable domain
.cakerenv files for multi-VM environments with dependency ordering, driven by up/down
Networking and sharing
- Bridged, hosted and NAT networks, created and managed with
cakectl networks
- Port forwarding between the VM and the host over TCP or Unix sockets, updated dynamically while VMs run
- Directory sharing through virtiofs
- IMDS: an instance metadata service for Linux guests
- Remote VNC access and an SSH-tunneled VNC client
Guest integration
- Cloud-Init support for VM initialization and customization
- Automatic installation of an in-guest agent, with source code in cakeagent, providing
exec, sh, IP discovery, resource metrics and live status
Automation and APIs
- gRPC API between
cakectl, Caker.app and caked
- Optional LXD-compatible REST API (
caked service listen --rest), so lxc and other LXD clients can talk to Caker
- A web UI served by
caked at /ui (sources in webui/)
- Long-running tasks (
build, launch, provision) can be listed and cancelled with cakectl tasks
Documentation
The documentation is automatically synchronized from the wiki/ directory to GitHub Pages when changes are pushed to the main branch.
Quick start
# Run the daemon as a launchd service, then drive it with cakectl
caked service install
cakectl list
# See the images you can build from, then create and start a VM
cakectl aliases
cakectl launch --alias ubuntu2604 myvm
# Open a shell in it
cakectl sh myvm
# Unattended macOS install from the catalog
cakectl build --alias macos15 --autoinstall mac-vm
# A multi-VM environment
cakectl compose init
cakectl compose up
See the getting started guide for the exact commands and options.
Components
| Component | Role |
|---|
caked | Core daemon: gRPC server, optional LXD REST API and web UI, launchd service, VM runner |
cakectl | CLI client that talks to caked over gRPC |
Caker.app | macOS desktop app and embedded VM runner |
Caked command line
caked is the core daemon process that handles virtual machine lifecycle management, including building, running, and orchestrating virtual machines with configuration-driven workflows. When it runs as a service, operate it through cakectl.
Cakectl command line
cakectl is the command-line interface used to interact with caked. It provides commands to:
- Build, launch and provision virtual machines
- Manage configurations, networks, templates, remotes and the image cache
- Run commands in guests, mount directories and open VNC sessions
- Manage Compose projects and inspect running tasks
- View status and control the daemon process
Caker.app
Caker.app is the macOS desktop application that provides a graphical experience for working with virtual machines managed by caked.
It acts as the user-facing control plane of the project and is designed for day-to-day local development workflows.
Its main role is to:
- Create and configure virtual machines from macOS with a guided wizard, including from the image catalog and the image cache
- Start, stop, pause and monitor virtual machine instances, in a mosaic or list view
- Embed and run standalone virtual machines directly in
Caker.app, or connect to a local or remote caked
- Show the live display of a VM, including during unattended installation
- Record a
boot_command template from your own clicks and keystrokes
- Manage networks, templates, remotes, Compose projects and running tasks
- Expose logs, status, and diagnostics in an accessible UI
- Integrate with the local daemon and CLI tooling without requiring manual low-level setup
A sandboxed App Store build is also available; a few features that need system access are unavailable there (see Sandbox).
Caked Service
caked can run as a launchd background service on macOS to run virtual machine workloads. It handles the core execution and management of virtual machines, including:
- Virtual Machine Lifecycle Management: Starting, stopping, and monitoring running virtual machines
- Resource Allocation: Managing CPU, memory, and storage resources for virtual machines
- Service Registration: Registering virtual machines as system services for persistent operation
- Health Monitoring: Continuously checking virtual machine health status and auto-recovery
- Live Status: Streaming CPU, memory, screenshots and state changes to connected clients such as
Caker.app
- Logging and Diagnostics: Collecting and streaming virtual machine logs and diagnostic information
Working in conjunction with cakectl, the command-line control interface, caked provides the backend daemon that executes administrative commands and maintains the operational state of all managed virtual machines.
Together, caked and cakectl form a powerful system for virtual machine development and deployment.
Building from source
swift build -Xswiftc -D -Xswiftc SPARKLE # CLI tools
swift test # unit tests
See the development guide for signed builds, the web UI and the integration tests.
Security
Please report vulnerabilities responsibly using the project's security policy:
Contributing
Contributions are welcome! Please feel free to submit a pull request or open an issue to report bugs or suggest enhancements.
