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Comment by nottorp | Hacker News Reader

So, since the host is mac os, you need to run a linux VM to be able to quickly instantiate a mac os VM?

With Apple's RAM prices?

Not quite, there's no need to run a Linux VM on macOS just to spin up macOS VMs.

Since the host is already macOS, we leverage the Apple Virtualization Framework (Vz) directly via a lightweight background service (lume). The Docker container (Lumier) acts purely as a frontend and delivery mechanism for managing and launching VMs — there's no nested virtualization or Linux VM involved.

That said, you're absolutely right that macOS hardware isn’t cheap, and RAM can be a real constraint. If you're running multiple VMs or aiming for production-scale setups, options like Scaleway’s M4 Mac minis or EC2 Mac Metal instances offer more headroom.

Also worth noting: while Lumier supports virtualizing Linux VMs too, if your use case is only Linux, there are far more cost-effective options using KVM on Linux hosts.

Docker uses a Linux VM to run on macOS.

Docker does seem to be an unnecessary overhead considering it's reliance on a Linux VM. What does Docker bring to the table that couldn't easily be replaced with a native Mac app?

Totally get your point. Docker isn’t about performance here. It’s just used as a management interface to connect to VMs running directly on the macOS host via Apple’s Vz. We went with this approach for Lume because Docker offers a familiar, automation-friendly workflow—great for CI, AI agents, and bundling things like noVNC

That was my point, and that was the Linux VM dependency that the OP doesn't realize exists.

Also there's some permanently running service. What's the point, to save 30 milliseconds out of the time to set up a VM which is certainly measured in tens of seconds?

The primary benefit here is automation and ease of management, especially for CI or AI agent workflows, rather than saving tiny amounts of time on VM setup. Docker's role is to offer a consistent and familiar management interface, which can be useful for automation and scaling, not for shaving milliseconds off VM boot times

What I think you’re not addressing is the question about the Linux VM that Docker requires on a Mac. I don’t think there is a question about the benefits of Docker from a management point of view. The question is — is it worth keeping around a running Linux VM just to get those management benefits. Since you’re not actually using Docker (the daemon) to run Macs in a container, how much of that micro Linux VM is necessary? Is that overhead worth it?

(This is coming from someone who keeps colima running all the time on my Mac)

Great question, and totally fair.

You're right that Docker on macOS runs inside a lightweight Linux VM (via Docker Desktop or Colima). We’re not using that VM to run the macOS guests - those run directly on the host via Apple’s Vz — but we do use Docker as a packaging and management layer (e.g. bundling noVNC, CLI tools, and configs).

So is it strictly necessary? Not really. But for teams already using Docker in CI/CD or automated workflows, it's often a tradeoff they're already making - and it means one less new tool/interface to adopt.

That said, we’re also looking into potentially using nested virtualization within the Docker daemon (which relies on Apple Vz under the hood) on M3+ chips, so as to remove the background service on the host entirely

> inside a lightweight Linux VM

Docker VMM, the latest virtualization option for Apple Silicon Macs, requires a minimum of 4GB of memory to be allocated to the Docker Linux VM.

Or so says an "AI", I'm not installing Docker on this laptop to check, I have limited RAM :)

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