Hey!

I have some questions as to how to setup the boot process for a linux guest (gentoo in my case) running as under XEN.

A bit of context: this is running as a virtual server I'm renting "in the cloud" (I think the hosting company is using XEN, since the root disk is called /dev/xvda1) and I'm in the process of updating the OS from an ancient gentoo to the latest.

Now, the old kernel (3.1.6) I have boots just fine (and has been running for the last few years just fine), the new one I'm trying to move to (4.14 as an intermediate step to modern times), does not. Sadly, I have no control nor visibility during the boot process... Earliest I can see what is going on is to ssh into the virtual server once it's running... So, I'm trying to really understand how it all works, to maximize my chances of success.

I have had a lot of help from the gentoo community also, but this now seems more a XEN issue than a specific gentoo one (which is why I'm asking here).

1.) My first question: it appears that grub2 is being used as a boot loader (because only modifying the grub.cfg file has any effect, which is a grub2 thing), but I don't even have grub2 installed, only grub 0.97... So, what exactly does XEN use to boot my virtual server? I tried to find out, but so far I've failed to understand. Do I even need to bother having grub or a bootloader installed in the virtual server?

2.) There's some inconsistencies in the system, for example, my /etc/fstab says to mount /dev/xvda as the root filesystem. This seems weird to me, as /dev/xvda seems like the whole disk, and also "mount" on the running system says it mounted /dev/xvda1 as the root system (and /dev/xvda1 is also what grub.cfg says to use as root). Also, there is no /dev/xvda on the running system. Could this be by design? Like, to protect the XEN host system from interferance from within the virtual guest? As you can see, I lack understanding also here....

3.) Do I need to use an initramfs, if I have enabled all the XEN options to be build into the kernel? As in, the kernel should, as far as I understand, already know how to mount a xen disk and how to use the xen network device... I have a feeling not having to use initramfs would simplify the whole situation to the point where I can get it to run on the new kernel...

Any advice/help/suggestions are greatly appreciated!