For users that are using their own images, we also provide source for all our customization to the images so you can integrate functionality into yours as required.

The code used on Linux to integrate the OS with the platform for ssh keys, startup script, auto-expanding root-disk, etc: https://github.com/GoogleCloudPlatform/compute-image-package...

For Windows, ssh keys aren't supported, however the platform has password reset built-in and starter scripts via metadata are also supported. Here's the code for the Windows agent: https://github.com/GoogleCloudPlatform/compute-image-windows

If running Windows, you will also need device drivers: https://github.com/GoogleCloudPlatform/compute-windows-drive...