How to access VM grub menu via VNC?

[pmensik]

Hey everyone,

I forgot my root password to one of the VMs I am running so I wanted to enter the GRUB menu to recover it. However, since I can only access the VM via noVNC web view (and ssh of course), I don't see the GRUB menu when booting to change its configuration. Is there any way to do it or do I have to recover the password via Live CD?

P.S. I tried to hold the Shift button, and press e or F10 but to no avail.

Thanks a lot for help

 

[fabian]

that depends entirely on how your VM was setup. but you do get control both at the bios/UEFI level, and if allowed, at the bootloader afterwards.

 

[pmensik]

that depends entirely on how your VM was setup. but you do get control both at the bios/UEFI level, and if allowed, at the bootloader afterwards.

Well, I did a standard installation of Ubuntu 22.0.4 and I don't remember enabling BIOs/UEFI. So is there a way how to set this up from the Proxmox GUI?

 

[fabian]

when you start the VM and hit `ESC` right at the start, you should end up in the firmware menu. from there, you can select which disk to boot and other things. how your particular bootloader is set up (and whether it's possible to modify those settings during bootup, or just from the booted OS as root) is not up to PVE at all.

 

[pmensik]

Yeah, but what I mean is that noVNC connects too late to the VM so when I can finally see the screen, the VM is already booting. So is there a different way how to connect to the VM from the Proxmox so I can see the boot menu on time and press Esc? Thank you

 

[fabian]

start novnc first, then reboot or start the VM from the novnc menu..

 

[pmensik]

start novnc first, then reboot or start the VM from the novnc menu..

Thak you, that worked. Although it seems that SeaBIOS doesn't allow to modify GRUB at least I was able to get to the menu.

 

[fabian]

like I said, what is allowed or not at the bootloader stage is up to the bootloader, not the firmware. it depends how you (or your OS) set it up - you can have it very open, or locked down.

 

[Kingneutron]

PROTIP - ' qm guest passwd vmid userid ' can RESET IN-VM PASSWORD if qemu-agent is running!

/ I learned something new today ;-) NOTE I have not tried this with root.

 

[mica85]

PROTIP

Thanks Kingneutron! This worked for me perfectly to reset a lost root pwd!

 

[NevadaTech]

PROTIP - ' qm guest passwd vmid userid ' can RESET IN-VM PASSWORD if qemu-agent is running!

/ I learned something new today ;-) NOTE I have not tried this with root.

Up vote this!
Thanks, worked for me on Proxmox 8.1.10 host with an Ubuntu 22.04 guest.
Remember to always install your qemu-guest-agent when you build your guests.