Tart Provider

Tart Provider

The Tart provider targets Apple Silicon macOS hosts and can run Ubuntu ARM64 or macOS ARM64 VMs.

EPAR currently validates the Ubuntu path:

• clone a reusable Tart image
• start the VM headless
• use the Tart guest agent for exec and IP discovery
• validate the base GitHub Actions runner runtime
• register an ephemeral GitHub runner from the host
• delete the VM after the runner exits

Use configs/tart.example.yml for the runner-only image or configs/tart.web-e2e.example.yml for the opt-in web/E2E install script.

When Docker/browser support is selected on ARM64, EPAR exposes a Chromium-compatible browser through epar-browser, chromium, and chromium-browser; it is not guaranteed to be Google Chrome.

The default network mode is Tart NAT. softnet is accepted by the provider, but it can require host-side privileges.

If Docker is installed in the guest, optional docker.registryMirrors settings are applied to the guest Docker daemon when each disposable VM starts. Use a mirror URL that is reachable from inside the Tart VM; host.docker.internal is Docker-container-specific and may not resolve in Tart guests. See Docker Registry Mirrors.

Rosetta For Linux Amd64 Containers

Tart on Apple Silicon runs ARM64 VMs, but Tart can expose Apple's Linux Rosetta runtime to the guest with tart run --rosetta <tag>. EPAR supports this as an opt-in Tart-only setting:

provider:
  type: tart
  rosettaTag: rosetta

When provider.rosettaTag is set, EPAR starts Tart instances with --rosetta rosetta, installs /opt/epar/setup-rosetta.sh during image build, enables epar-rosetta.service, and registers an x86_64 Linux binfmt_misc handler inside the guest. Images with the Rosetta feature marker validate:

sudo -u runner -H docker run --rm --platform linux/amd64 alpine:3.20 sh -c 'uname -m'

The expected output is x86_64.

Host prerequisites:

• Apple Silicon macOS
• Tart version with --rosetta support
• Apple's Rosetta package installed on the macOS host

This is for Linux amd64 user-space containers. It is not nested virtualization and it does not make the Ubuntu VM an x64 VM. For native amd64 performance and compatibility, use a Windows WSL x64 provider or another x64 Linux host. For Tart Rosetta-capable runners, expose a distinct label such as epar-tart-rosetta-amd64 so workflows can opt into the behavior explicitly.