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Comment by embedding-shape

17 hours ago

Doesn't this assume you bi-directionally share directories between the host or the VM? Or how would the AI inside the VM be able to write to your .git repository or Vagrantfile? That's not the default setup with VMs (AFAIK, you need to explicitly use "shared directories" or similar), nor should you do that if you're trying to use VM for containment of something.

I basically do something like "take snapshot -> run tiny vm -> let agent do what it does -> take snapshot -> look at diff" for each change, restarting if it doesn't give me what I wanted, or I misdirected it somehow. But there is no automatic sync of files, that'd defeat the entire point of putting it into a VM in the first place, wouldn't it?

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embedding-shape

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lucasluitjes  15 hours ago

It's the default behaviour for Vagrant. You put a Vagrantfile in your repo, run `vagrant up` and it creates a VM with the repo folder shared r+w to `/vagrant` in the VM.

  • embedding-shape  15 hours ago

    That's because Vagrant isn't "VM", it's a developer tool you use locally that happens to use VMs, and it was created in a era where 1) containers didn't exist as they do today, 2) packaging and distribution for major languages wasn't infected with malware and 3) LLM agents now runs on our computers and they are kind of dumb sometimes and delete stuff.

    With new realities, new workflows have to be adopted. Once malware started to appear on npm/pypi, I started running all my stuff in VMs unless it's something really common and presumed vetted. I do my banking on the same computer I do programming, so it's either that or get another computer.

    • lucasluitjes  1 hour ago

      Agree with all of that, especially modern supply chain risk (imho the more important reason to opt for VM isolation rather than containerization). But the original article specifically talks Vagrant as an isolation solution, and describes it as not protecting against VM escape, but also that guest-to-host 0day is rare.

      Hence pointing out that VM escape is a lot easier than that if your VM management tool syncs folders the way that Vagrant does by default.