alt.hn

1/18/2026 at 5:53:21 PM

Show HN: Lume 0.2 – Build and Run macOS VMs with unattended setup

 https://cua.ai/docs/lume/guide/getting-started/introduction

by frabonacci

1/18/2026 at 9:28:21 PM

I tried to set up a macOS VM recently so I could run an old version of iTunes to manage my iPods. I found it nearly impossible to even download an installer for older versions of the OS, and could never get it working. Where can one acquire an IPSW for, say, macOS Mojave? My understanding is this is not the same thing as the “Install macOS.app”?

by cmckn

1/19/2026 at 3:49:39 AM

I like to use MIST (macOS Installer Super Tool) to grab old macOS versions: https://github.com/ninxsoft/Mist

Apple also provides instructions for downloading many older macOS versions via your terminal: https://support.apple.com/en-us/102662#terminal

by CharlesW

1/19/2026 at 4:22:16 AM

Nice, thanks for sharing! It'd be interesting to integrate MIST into lume's ipsw command - right now Apple's native features in Apple Vz only provides download links for the latest supported version of the host, so grabbing older versions requires workarounds like this.

by frabonacci

1/18/2026 at 9:36:00 PM

For a version of macOS that old, you’d probably want a dmg, which you can create with createinstallmedia if you have the Install macOS.app. Not sure if it’s supported with Lume as it’s the first time I’ve heard of it.

by samtheprogram

1/18/2026 at 9:58:56 PM

Mojave never was an IPSW, because it never ran on Apple Silicon. I imagine this tool might just not support that at all.

by LoganDark

1/18/2026 at 10:18:49 PM

LoganDark is right. I've personally never tried, and don't think it'd be easy for any macOS predating Apple Virtualization Framework. For that you'd need something like UTM since they're relying on QEMU - these configs might help: https://github.com/adespoton/utmconfigs

by frabonacci

1/18/2026 at 11:03:36 PM

Ahh I see. UTM was what I was trying, so I’ll give those a look! Thanks

by cmckn

1/18/2026 at 10:25:48 PM

I was trying to do something similar last year and gave up because it felt futile. That said, it was the push I needed to try Rockbox, and I haven't looked back. Managing things via the file system is really nice.

by illithid0

1/19/2026 at 12:11:15 AM

I started on my Linux box and despite many apps claiming to support iPods, none would actually work. I ended up getting an old Mac mini running again and I’m using that for now. I’ve never given Rockbox a good look, I should check it out.

by cmckn

1/25/2026 at 11:36:24 AM

I already use UTM and make a gold standard image that I setup once as beginning state snapshot. What am I missing here? This seems like it would take longer and more brittle to do the same thing? I also configure RAM, HD size, and CPU as well as networking and shared drives.

by jamescampbell

1/18/2026 at 10:07:12 PM

I believe this is using Virtualization.framework and not Containerization API from Tahoe, right?

Is there a limit on number of instances you can have per physical mac? i recall there was a hard limit of 2 because of EULA, unless Apple has changed it. (Cupertino really likes to sell you their Macs)

by ahmadyan

1/18/2026 at 10:26:00 PM

Correct, Containerization APIs are Linux VMs specific.

There's a kernel-level check in the Hypervisor framework that enforces the 2 VM limit, and bypassing it violates Apple's EULA.

Nice technical deep-dive on the how here: https://khronokernel.com/macos/2023/08/08/AS-VM.html

by frabonacci

1/19/2026 at 1:30:44 AM

"We built a VNC + OCR system that clicks through macOS Setup Assistant automatically" - that is both awesome and annoying. I guess I assumed that Apple supported some form of unattended setup.

by abrookewood

1/19/2026 at 1:50:01 AM

Yeah, Apple intentionally provides no unattended setup. Plus any process trying to control the UI programmatically needs explicit accessibility permissions, which defeats the purpose.

So we just click through like a human would via VNC. Version-specific but works with their security model rather than against it.

by frabonacci

1/21/2026 at 4:54:51 AM

That's a great approach.

by abrookewood

1/19/2026 at 1:46:09 AM

How does this compare to something like Tart and shapehq/tartelet

by fartfeatures

1/19/2026 at 1:53:47 AM

Both use Apple's Virtualization Framework, so core VM performance is similar. Main differences are around agent-first design (HTTP API, MCP server), unattended setup via VNC + OCR, and registry support for VM images.

We've also built a broader ecosystem on top - the Cua computer and agent framework for building computer-use agents: https://cua.ai/docs

We went through the comparison with Tart, Lima etc here: https://github.com/trycua/cua/issues/10

by frabonacci

1/19/2026 at 2:28:17 AM

Thanks for answering, makes sense.

Not seeing any reference to Tart at that link. Tart also has registry support for VM images it treats them very much like Docker images, is that what you are doing too?

Is it worth putting a comparison up somewhere other than a Github thread? Seems to be a frequently asked question at this point.

Also worth drawing attention to Tart being source available not open source.

by fartfeatures

1/19/2026 at 4:25:59 AM

Thanks for the feedback! You're right that a proper comparison page beats hunting through GitHub issues.

We just put one together (with some help from Claude Code, naturally): https://cua.ai/docs/lume/guide/getting-started/comparison

by frabonacci

1/19/2026 at 5:38:45 AM

Thanks much appreciated, the "Registry Support" section is weird though. Isn't GHCR an instance of an OCI registry? The when to choose Loom in the Tart section should also mention licensing, it is relevant at the choosing point.

by fartfeatures

1/19/2026 at 5:46:14 AM

Good catches, thanks! Just updated the page:

Fixed the registry description—you're right, GHCR is an OCI registry. Both tools use OCI-compatible registries, we just default to GHCR/GCS.

Added licensing to the "when to choose" sections.

by frabonacci

1/19/2026 at 8:19:06 PM

Good changes, like the new theme too, I'd still match the two boxes if it were me (both should read OCI registry and optionally include GHCR but they should be identical)

by fartfeatures

1/19/2026 at 11:45:11 AM

> Lume automates the macOS Setup Assistant via VNC and OCR, creating ready-to-use VMs without manual clicking. Tart relies on Packer plugins for automation.

This feels disingenuous. Tart has unattended setup support as well, and it's based on the same VNC + OCR technique as Lume. In fact Tart had it first, and your approach seems to be heavily inspired by it. In addition the boot command instructions you're using came from https://github.com/cirruslabs/macos-image-templates/

The only material difference is whether it's built-in or integrated via Packer.

by torarnv

1/20/2026 at 1:14:23 AM

Fair point - both use VNC for unattended setup. The difference is implementation: Tart does it via a Packer plugin (Go), we built it natively in Swift with a customizable YAML schema that's less error-prone. User-facing difference is --unattended flag vs Packer workflow.

by frabonacci

1/18/2026 at 7:31:43 PM

Sorry for the naive question but specifically for running Claude on a sandbox, why do people decide to use lume as opposed to running it on Docker?

by whinvik

1/18/2026 at 7:36:14 PM

Docker on Mac runs Linux containers inside a Linux VM - you can't run macOS in Docker. So if you need Claude / Codex / OpenCode to interact with:

- macOS GUI apps (Xcode, Numbers, Safari, etc.) - macOS desktop automation (screenshots, mouse/keyboard input, accessibility APIs) - macOS CI/CD (building iOS/macOS apps, running XCTest)

...you need an actual macOS VM, which is what Lume provides.

by frabonacci

1/18/2026 at 8:51:44 PM

I wonder what the additional layer of virtualization changes with respect to this in a project like this one: https://github.com/dockur/macos

The unattended setup is a large improvement, which also begs the question: Mac OS doesn't have an unattended.xml alternative for its installer?

by fishtacos

1/18/2026 at 8:59:57 PM

macOS has unattended setup options via MDM or Apple Configurator…

by happyopossum

1/18/2026 at 9:10:11 PM

Can you do zero touch without having an Apple Business account (so, a DUNS number) and a MDM?

I thought this was a silly way to do it too, but upon reflection I don’t know if you can zero touch setup a Mac without registering a device in DEP.

by easton

1/18/2026 at 10:12:20 PM

re: unattended setup.

You're both right - Apple's official zero-touch setup requires MDM + DEP, which needs Apple Business Manager (and yes, a DUNS number).

But for VMs specifically, DEP doesn't work anyway - VMs don't have real serial numbers that can be enrolled in Device Enrollment Program.

VNC-based setup automation is the only practical option - it's what the ecosystem has converged on for macOS VMs. Lume connects to the VM's VNC server and programmatically tabs, clicks, types through Setup Assistant.

by frabonacci

1/18/2026 at 11:40:11 PM

I wish the virtualization framework would allow you to simulate your own MDM stuff. Would be very useful for integration testing MDM implementations themselves...

by arianvanp

1/25/2026 at 11:40:43 AM

If you run say ollama in docker vs native you lose MPS (metal core like the way CUDA works but Mac) which is really a deal breaker to do any AI work via docker for doing things with local models, which is my use case to have a full fast VM inside my mac.

by jamescampbell

1/19/2026 at 4:00:48 AM

Looked at Lume before and it was already very impressive then. For this unattended use case this looks amazing.

Slight tangent - do the VMs have decent graphics performance? I live in fear of one day accidentally pressing the Update button and being forced into the GUI mess that is Tahoe. Knowing I could just use a VM with Sequioa as my primary desktop would dramatically lower my anxiety.

by JSR_FDED

1/19/2026 at 4:24:04 AM

Thanks! On graphics - currently it's paravirtualized via Apple's Virtualization Framework, so basic 2D acceleration but no GPU passthrough. Fine for desktop use, web browsing, coding, productivity apps. Wouldn't recommend it for anything GPU-intensive though.

Good news is there are hints of GPU passthrough coming (_VZPCIDeviceConfiguration symbol appeared in Tahoe's Virtualization framework), so that might land in a future macOS release. We're keeping an eye on it.

by frabonacci

1/19/2026 at 7:08:34 AM

> We built a VNC + OCR system that clicks through macOS Setup Assistant automatically.

You can automate at least some of this with `defaults write` commands or copying files to the right places. If you look at what some existing MDM platforms do you should be able to do this a lot more efficiently.

by JimDabell

1/19/2026 at 7:23:26 AM

MDM platforms can skip Setup Assistant, but they require the device to be pre-enrolled in Apple Business Manager before first boot - VMs can't be enrolled in ABM, so those hooks aren't available.

defaults write only works after you have shell access, which means Setup Assistant is already done.

There are tools that modify marker files like .AppleSetupDone via Recovery Mode, but that's mainly for bypassing MDM enrollment on physical Macs - you'd still need to create a valid user account with proper Directory Services entries, keychain, etc.

The VNC + OCR approach is less elegant but works reliably without needing to reverse-engineer macOS internals or rely on undocumented behaviors that might break between versions.

by frabonacci

1/19/2026 at 10:42:22 AM

Surely your VNC script is guaranteed to break between versions

by saagarjha

1/18/2026 at 10:33:32 PM

How is the networking? Tart broke networking in Tahoe. Would love to see this work, setting up base images has always been a massive pain.

by eptcyka

1/18/2026 at 10:40:44 PM

We haven't observed any networking degradation with Lume on Tahoe so far - things have been working smoothly in our testing. Give it a try and let us know if you run into any issues!

by frabonacci

1/19/2026 at 8:20:06 AM

Can you elaborate on what got “broken” on Tahoe?

by fkorotkov

1/19/2026 at 9:40:51 AM

This at least feels more natural than writing Swift scripts.

by pjmlp

1/20/2026 at 12:22:56 AM

The MCP Server integration is a great addition - being able to have Claude manage VMs directly opens up interesting sandboxing patterns for agent workflows.

One thing I've been thinking about with agents running in isolated environments: how do you handle visibility into what API calls the agent is making from within the VM? Right now we rely on proxying outbound requests to see what's actually happening. Does Lume expose any of that through the MCP interface?

Nice work on the unattended setup - that's usually the painful part.

by kxbnb

1/20/2026 at 1:10:37 AM

Thanks! On API call visibility - Lume's MCP interface doesn't expose outbound network traffic directly. It's focused on VM lifecycle (create, run, stop) and command execution, not network inspection.

For agent observability, we handle this at the Cua framework level rather than the VM level:

- Agent actions and tool calls are logged via our tracing integration (Laminar, OpenTelemetry) - You can see the full decision trace - what the agent saw, what it decided, what tools it invoked - For the "what HTTP requests actually went out" question, proxying is still the right approach. You could configure the VM's network to route through a transparent proxy, or set up mitmproxy inside the VM. We haven't built that into Lume itself since network inspection feels orthogonal to VM management.

That said, it's an interesting idea - exposing a proxy config option in Lume that automatically routes VM traffic through a capture layer. Would that be useful for your workflow?

by frabonacci

1/18/2026 at 6:56:38 PM

[dead]

by frabonacci