I'm happy to see this, and I have lots of thoughts about this. Building declarative services on Nix is a far superior way of distributing Linux to VMs than most any other way I've tried. I am working [1] on very similar things, but I've been leaning more on the self-hosted path, my VM template targets libvirt and Proxmox VE with a single CLI api. I even have an experimental branch that targets DigitalOcean. For VMs especially, I want my OS to be immutable. My VMs should contain no state other than my application state. Upgrades should be a full image replacement and reboot.
So in my template, I have created the VMs with two disks: first one is for NixOS and is built from an image, and it is read-only. The second is mounted to /var and is used for all system configuration as well as application state. If I have multiple VMs, they can all share the same base image (thin provisioned). That's the mode that I want for my deployments of services, immutable and as stateless as possible. For agent use, its different, you actually want a mutable NixOS root so that the agent can do what it wants.
I built three modes: immutable, semi-mutable, and mutable. mutable removes the read-only lock on the root, and just lets you manage the VM as a pet. semi-mutable adds an ephemeral overlayfs that gets wiped the next time you upgrade the base image. So that gives you kind of the best of both worlds: an immutable read-only base image and the ability to "nix profile add" whatever you (or your agent) wants, but with the contract that these imperatively installed things will disappear the next time you upgrade. Are you planning on adding a LICENSE to your machine0-nixos repo?
Thanks! Yup, one of the benefits of defining your VMs as code using Nix, is that you can take that code to any supplier, and you're guaranteed exactly the same build.
How does machine0 handle NixOS state drift and recovery in practice—for example, if a VM is manually modified outside the flake, can I detect or reset that drift, and how do snapshots interact with flake-based provisioning?
I'm happy to see this, and I have lots of thoughts about this. Building declarative services on Nix is a far superior way of distributing Linux to VMs than most any other way I've tried. I am working [1] on very similar things, but I've been leaning more on the self-hosted path, my VM template targets libvirt and Proxmox VE with a single CLI api. I even have an experimental branch that targets DigitalOcean. For VMs especially, I want my OS to be immutable. My VMs should contain no state other than my application state. Upgrades should be a full image replacement and reboot.
So in my template, I have created the VMs with two disks: first one is for NixOS and is built from an image, and it is read-only. The second is mounted to /var and is used for all system configuration as well as application state. If I have multiple VMs, they can all share the same base image (thin provisioned). That's the mode that I want for my deployments of services, immutable and as stateless as possible. For agent use, its different, you actually want a mutable NixOS root so that the agent can do what it wants.
I built three modes: immutable, semi-mutable, and mutable. mutable removes the read-only lock on the root, and just lets you manage the VM as a pet. semi-mutable adds an ephemeral overlayfs that gets wiped the next time you upgrade the base image. So that gives you kind of the best of both worlds: an immutable read-only base image and the ability to "nix profile add" whatever you (or your agent) wants, but with the contract that these imperatively installed things will disappear the next time you upgrade. Are you planning on adding a LICENSE to your machine0-nixos repo?
[1] https://github.com/EnigmaCurry/nixos-vm-template
Always happy to meet others that are working with NixOS :) I've just added the License - it's MIT.
I’ve been using machine0 for hosting openclaw and a couple of web apps i’ve been working on. Great product super easy to use with claude code.
Been great having you :)
Big fan of exe.dev so the added Nix seems like a solid value add.
exe.dev is great but lurking in my mind is: "how will I replicate this if I ever need to move to AWS etc.." for all the service composition.
Site looks great too
Thanks! Yup, one of the benefits of defining your VMs as code using Nix, is that you can take that code to any supplier, and you're guaranteed exactly the same build.
How does machine0 handle NixOS state drift and recovery in practice—for example, if a VM is manually modified outside the flake, can I detect or reset that drift, and how do snapshots interact with flake-based provisioning?
It's not possible to modify the VM outside of the flake :)
Great product, with great explanation
Thank you!