Using disko with Macbook (Asahi NixOS)

[sezaru]

Sorry for creating an issue for a question, but I tried to search for documentation on this specific topic and found only mixed information.

So, the question is, is it possible to use disko to manage the disks for NixOS inside a disk that also has MacOS?

For installing NixOS in a Macbook Pro, you can't wipe the full disk, you will first need to free space from the MacOS installation that you can later, install the system inside. This part is done directly in MacOS via the Asahi script, so that part I obviously don't expect disko to handle.

The question is more about after that part, so, when I boot into the NixOS installer, I will have already the partitions available that I can then format, create sub-volumes (if using btrfs), etc. This part right now I do manually, but I would love to be able to do it with disko so I have a installation that is closer to how it is done in my other machines.

Running lsblk --output KNAME,PATH,LABEL,PARTLABEL,PTTYPE --tree --json, I got this:

{
   "blockdevices": [
      {
         "kname": "nvme0n1",
         "path": "/dev/nvme0n1",
         "label": null,
         "partlabel": null,
         "pttype": "gpt",
         "fstype": null,
         "size": "233.8G",
         "uuid": null,
         "children": [
            {
               "kname": "nvme0n1p1",
               "path": "/dev/nvme0n1p1",
               "label": null,
               "partlabel": "iBootSystemContainer",
               "pttype": "gpt",
               "fstype": "apfs",
               "size": "500M",
               "uuid": "9362fb83-a489-4ebf-8f54-918031fddce0"
            },{
               "kname": "nvme0n1p2",
               "path": "/dev/nvme0n1p2",
               "label": null,
               "partlabel": "Container",
               "pttype": "gpt",
               "fstype": "apfs",
               "size": "78.2G",
               "uuid": "2dd7f090-0814-46f4-b603-7dacfe0293f4"
            },{
               "kname": "nvme0n1p3",
               "path": "/dev/nvme0n1p3",
               "label": null,
               "partlabel": null,
               "pttype": "gpt",
               "fstype": "apfs",
               "size": "2.3G",
               "uuid": "5ec6396a-8db9-4532-b7ea-2476639d067c"
            },{
               "kname": "nvme0n1p4",
               "path": "/dev/nvme0n1p4",
               "label": "EFI - NIXOS",
               "partlabel": null,
               "pttype": "gpt",
               "fstype": "vfat",
               "size": "477M",
               "uuid": "78ED-17F1"
            },{
               "kname": "nvme0n1p5",
               "path": "/dev/nvme0n1p5",
               "label": "nixos",
               "partlabel": null,
               "pttype": "gpt",
               "fstype": "ext4",
               "size": "71.8G",
               "uuid": "46b683e5-e54e-4d9e-b13d-dfb41e5ff2a1"
            },{
               "kname": "nvme0n1p6",
               "path": "/dev/nvme0n1p6",
               "label": null,
               "partlabel": "RecoveryOSContainer",
               "pttype": "gpt",
               "fstype": "apfs",
               "size": "5G",
               "uuid": "c7367236-5629-4811-b689-03c37f9eb961"
            }
         ]
      }
   ]
}

As you can see, nvme0n1 is the SSD used.

/dev/nvme0n1p1, /dev/nvme0n1p2 and /dev/nvme0n1p6 Are MacOS partitions.

/dev/nmve0n1p3 is an APFS partition created by Asahi which I believe that is needed to boot.

/dev/nvme0n1p4 is the NixOS EFI boot partition and /dev/nvme0n1p5 is the NixOS root partition.

What I want to do is a disko config that would format and use /dev/nvme0n1p4 and /dev/nvme0n1p5 for the NixOS installation, but leave the other partitions alone so it doesn't wipe the whole disk or format the MacOS partitions bricking the device.

Is that possible?

[Mic92]

We have an incremental mode called disko --mode format,mount in our cli, which is supposed to only create new partitions. However I would for safety pass the --dry-run flag and review the generated format script (potentially even running commands that it generates, manual to be on the safe side). Leave partitions that should be just kept as is without any filesystem, so it's only adding filesystems to new partitions - you also don't want to mount those anyway. You might have to shrink your existing macOS partition already before.

[sezaru]

So, I made this disko config as a starting point:

{
  disko.devices = {
    disk = {
      main = {
        device = "/dev/nvme0n1";
        type = "disk";

        content = {
          type = "gpt";

          partitions = {
            iBootSystemContainer = {
              # size = "500M";
              size = "524288K";
              type = "AF0B";
            };

            Container = {
              # size = "78.2G";
              size = "83914392K";
              type = "AF0A";
            };

            NixOSAppleBoot = {
              # size = "2.3G";
              size = "2499805K";
              type = "AF0A";
            };

            NixOSEFI = {
              priority = 1;

              name = "EFI - NIXOS";
              # size = "477M";
              size = "500171K";
              type = "EF00";

              content = {
                type = "filesystem";
                format = "vfat";
                mountpoint = "/boot";
                mountOptions = [ "defaults" ];
              };
            };

            NixOSRoot = {
              name = "nixos";
              # size = "71.8G";
              size = "77106446K";
              type = "8300";

              content = {
                type = "filesystem";
                format = "ext4";
                mountpoint = "/";
                mountOptions = [ "noatime" ];
              };
            };

            RecoveryOSContainer = {
              # size = "5G";
              size = "5368664K";
              type = "AF0C";
            };
          };
        };
      };
    };
  };
}

And then I tried to run it with disko -m format,mount --dry-run disko.nix, but I'm not sure how I should interpret the output:

❯ disko -m format,mount --dry-run disko.nix
disko version 1.12.0
/nix/store/i4nv4qmzfhpziyklhqlwsvg564dfyn9c-disko-format-mount/bin/disko-format-mount

[vidhanio]

@sezaru Take a look at my config. The only caveat is that you MUST manually update the UUIDs in your config before you run disko --mode format,mount path/to/disk.nix, or your computer will lose track of the partitions and you will have to DFU restore. Use at your own risk. https://github.com/vidhanio/vidhanix/blob/f754f821bd8ed870deccbcf72927a07da5b1bb64/hosts/vidhan-macbook/disk.nix