We don't have on-demand API-based bare metal provisioning right now. Sorry if that is misleading on the website. Our bare metal is OTC right now (over the counter).

For the rest of our provisioning (VM and container) I wrote the software myself. It's based on a Django app called the "master" that hosts the console and keeps track of who has rented what etc + a bunch of "host" nodes that listen for instructions from the "master". Pure python, the only thing that's in Go is the CLI.

I looked into Proxmox but ultimately decided I wanted full control. ZFS storage from Proxmox is something I do sometimes wish we had — going to offer s3-compatible storage very soon but I know Proxmox does ZFS out of the box really well.