- `token` (string) - The authentication token used to access your account. This can be either a session token or a service account token. If not defined, the builder will attempt to find it in the following order: - `project` (string) - The id or name of the project. This field is required only if using session tokens. It should be skipped when using service account authentication. - `source_image` (string) - ID or name of the image to launch server from. - `vm_type` (string) - ID or name of the type this server should be created with. - `disk_size` (float32) - Size of the created disk, in GiB.