Has been changed some month ago, I would say,
Yes, you do not have to install the backup plug-in for clonezilla.
The rest of this guide should be still ok: Headless Backup of the System Drive with Clonezilla
Is the above guide still valid in terms of being able to do it headless? I installed Clonezilla under OMV-Extras - Kernel tab. I then clicked "Reboot Clonezilla Once" to set up the bootloader. Then I clicked reboot on the OMV button on the upper right. It does work in that it boots into Clonezilla. However, it will not connect when using Putty even though it has a static IP. When I connect directly through HDMI I can see that Clonezilla has loaded, but it is asking setup questions about language, keyboard map, etc. It always asks for these questions, so it really never loads fully until I answer them. Any suggestions? I am doing something wrong?