We have our own Terraform module that currently creates and modifies VPSes on our infrastructure, uploads public SSH keys and runs commands over SSH.
Terraform manages infrastructure using configuration files. It supports many hosting, cloud and similar providers. You can now use it to configure our VPSes too.
The plugin, installation instructions and an example are on GitHub.
Please report bugs in the repository. You're also welcome to contribute: support for managing datasets and mounts still needs to be added, and there are bound to be other things.
Terraform plugins are easiest to write in Go, so we also needed a Go client for our API. Since our API can document itself neatly, the Go client is generated entirely automatically. The result is a HaveAPI Go client library generator and the client for our API, which can be used independently of Terraform.