[Feature]: Allow creating new server with NixOS iso image

[onnimonni]

What whould you like to see?

Hey,

I can see that nixos base image is already available in the admin panel after server has been created:

But when I try use it:

resource "hcloud_server" "my-server" {
  name        = "my-server"
  # nixos-minimal-25.05.803396.8f1b52b04f2c-aarch64-linux.iso
  image       = "nixos-minimal-25"
  server_type = "cax11"
  datacenter  = "hel1-dc2"
}

I get error:

$ opentofu apply -auto-approve
Plan: 1 to add, 0 to change, 0 to destroy.
hcloud_server.my-server: Creating...
╷
│ Error: image nixos-minimal-25 for architecture arm not found

Would you be willing to add this into the API and to the terraform provider too?

I think it's mainly missing as an option to the API since I can't find it when searching for all images:

data "hcloud_images" "arm" {
  with_architecture = ["arm"]
}
output "arm" {
  value = data.hcloud_images.arm
}

[jooola]

An Hetzner Cloud ISO is not the same an Hetzner Cloud Image, an ISO cannot be used as Image.

What you can do is create a server and then mount the ISO on the server using the ISO argument:
https://registry.terraform.io/providers/hetznercloud/hcloud/latest/docs/resources/server#argument-reference

resource "hcloud_server" "my-server" {
  name        = "my-server"
  image       = "debian-13"
  server_type = "cax11"
  datacenter  = "hel1-dc2"

  iso = "nixos-minimal-25.05.803396.8f1b52b04f2c-aarch64-linux.iso"
}

Then, you should be able to perform the manual installation from the ISO after a server reboot.

[onnimonni]

TIL! Thanks for the great answer and teaching about the difference to me 🙇

Is there a api where I could list the available ISO images like the nixos-minimal-25.05.803396.8f1b52b04f2c-aarch64-linux.iso?

[onnimonni]

It indeed worked and I can now see that my server is running nixos when I access the vps through the cloud console.

Is there anyway to attach trusted ssh key when mounting to an ISO?

The default passwords are empty and there is are no ssh keys: