Does Tart support nested virtualization?

[jonathandieu]

I'd like to be able to run Docker Desktop when running workflows with these runners- is that something that's possible using Tart / Cirrus runners?

Thanks in advance

[fkorotkov]

Unfortunately, it's not supported at the moment by the Virtualization.Framework that Tart depends on even though M1/M2/M3 chips have the hardware capabilities.

[jonathandieu]

Thanks for the speedy response! 🙇

[rpendleton]

Looks like Virtualization.framework might be adding support for nested virtualization starting in macOS 15:

https://developer.apple.com/documentation/virtualization/vzgenericplatformconfiguration/4360552-isnestedvirtualizationenabled?changes=latest_minor

[fkorotkov]

Unfortunately only for Linux VMs. Nothing for macOS 😢

[sorenbs]

Does Tart support running a Linux guest with nested virtualization?

[edigaryev]

Please see #933.

[fkorotkov]

As of version 2.20.0 you can enable nested virtualization for Linux VMs by passing --nested flag to tart run.

[fkorotkov]

Unfortunately, Tahoe didn't change it. Even Linux VMs inside macOS VMs will be super beneficial.

[nohajc]

Of course. I just have a very specific use case - developing a project which uses a Linux microVM on macOS. I can automate builds on multiple OS versions using tart but can't run any tests which would involve starting a nested Linux VM by design.

So if I understand it correctly, this is something Apple needs to address, right? Is it even documented anywhere or it's just trial and error on our part?

Thanks!

[fkorotkov]

This use case should be supported on M3/M4 with tart run --nested. It's only not possible inside of macOS guests and on M1/M2.

[nohajc]

Yeah, unfortunately I need the macOS guest with nested Linux. Let's hope Apple enables that soon.

[nohajc]

I meant to ask whether Apple documents the fact it doesn't support nested virtualization for macOS guests.

I think tart's documentation is OK. :)