(2020/05/18) If you have a remote server with one Linux OS1 running and you need to install another OS2, but you do not have remote installation media facility on your IPMI/KVM hardware, you can first create a satisfactory virtual machine locally, collect the filesystem dump from there, restore to a second partition of the remove server, and then get into OS1 grub command line, where you have to maintain serial tty connection to OS2 as it boots, as follows (adjust to your hardware).
search.file /etc/issue --set-root
linux /boot/vmlinuz... root=... ro console=tty0 console=ttyS1,19200n8
Once booted to OS2, edit /etc/default/grub to reflect serial tty
options, run update-grub, but do not let OS2 overwrite MBR/EFI
(unless you wish to). Instead, reboot to OS1 and runs its
update-grub so now it knows how to boot OS2 from grub menu.