Reduce size of GCE bootstrap images

[3noch]

The GCE bootstrap images are 100GB and you cannot create an instance with a root disk smaller than the bootstrap image. This means that creating a GCE instance with an SSD is at least $12/month more than using a standard disk. In most cases you do not need instances with 100GB of disk space (or you'd offload that to a single database server).

How hard would it be to build a new image that's smaller and make that the default?

[rbvermaa]

Should be easy, just need to test if somehow we can allow growing the partition if needed/specified.

[clefru]

I have built a 1GB image that includes partition growing. Please test with::

  resources.gceImages.bootstrap = credentials // {
    sourceUri = "gs://nixos-images-clefru/nixos-image-17.03.git.f119e1d-x86_64-linux.raw.tar.gz";
  };

  fooinstance = {
    deployment.gce = credentials // {
       rootDiskSize = 30;
    };
  };

clefru/nixpkgs@3d43324 is the commit. I built this from https://github.com/clefru/nixpkgs/tree/gce-image-shrink which is channels/nixos-17.03 from about yesterday, plus the NixOS/nixpkgs#24143 cherry-picked. The cherry-picking is necessary otherwise the kernel used during the QEMU build phase will corrupt data when talking to /nix/store via 9p. You suffer from this bug if your "cp" command complains about hard-links in /nix/store.

Don't depend on my image to hard (or make a copy), as I will eventually remove it after 17.03 is out and has its own official images.

[3noch]

@clefru Wow this is awesome! Great work!

[domenkozar]

See NixOS/nixpkgs#24360

[clefru]

My original image only resized the partition, not the filesystem within. The following image should work better:

  resources.gceImages.bootstrap = credentials // {
    sourceUri = "gs://nixos-images-clefru/nixos-image-17.03.git.d0e4b3f-x86_64-linux.raw.tar.gz";
  };

[Mic92]

was fixed by NixOS/nixpkgs#24360 and can be closed

[domenkozar]

We should first update images?

[domenkozar]

Fixed in c28a4f7