Ask HN: 2020 state of the art baremetal provisionning?

With the explosion of virtualisation, cloud, container, it seems baremetal is suffering from loss of interest. But still baremetal racking and provisioning are essential to provide hardware support, cpu and storage to any kinds of upper layers. From an opensource perspective, and editor free, what are the best 2020 solutions to manage thousand of baremetal servers in multi data centers, distro agnostic ? Are we still stuck with bootp/tftp kickstart or preseed? What if I want to masterise servers as agile as popping a VM in a cloud service ? Are most company managing thousand of thousand of servers using homemade solution ? Or does an on the shelve solution exist?