What is the least painful way to upgrade Proxmox from 3 to 5?

Question

Proxmox

I have a Proxmox 3 on Debian 7 machine installed from the hetzner distribution
How can I upgrade to Proxmox 5 on Debian 9 with the least effort? it is not possible to transfer virtual machines to another machine because of their size.

Answer 1

according to the official instructions, it was updated without problems, I only had to replace the hetzner repositories with the standard debian repositories, there were no 4.4+ kernels in the hetzner repositories

Answer 2

proxmox 3 in my opinion still on openvz
if you don’t have openvz machines
then just upgrade to the eighth debian with the eighth proxmox according to the instructions
and from it to the nine and fifth proxmox
with kvm machines nothing will happen
openvz
it’s not a tricky thing to die but without backup you obviously risk losing all data
if anything please contact