I have a XEN server with a PV guest. I would like to change the guest boot parameters. These are my current parameters inside the PV guest, and I want to add another one.
$ cat /proc/cmdline
root=/dev/xvda2 ro elevator=noop root=/dev/xvda2 ro
Normally, without virtualization, I would edit /etc/default/grub, and then run update-grub. However, inside the PV guest, the file /etc/default/grub does not even exist.
I was trying to find solution the internet, and saw that the boot loading process and grub behave differently in PV XEN environments then in native or HVM, but I got completely lost in the difference between pygrub, pvgrub and don't know what I have or how to change them.
This is the guest linux version:
$ uname -a
Linux tutorial-pv-guest 4.4.0-142-generic #168-Ubuntu SMP Wed Jan 16 21:01:15 UTC 2019 i686 i686 i686 GNU/Linux
This is the host:
$ uname -a
Linux d-119-237 4.9.0-8-amd64 #1 SMP Debian 4.9.144-3.1 (2019-02-19) x86_64 GNU/Linux
Can somebody please help me to understand how to change the guest boot parameters?
Thanks!
I found the solution myself.
I had to add in the .cfg file used to boot the guest the line extra="myflag" right after the line bootloader='/usr/lib/xen-4.8/bin/pygrub'