Proxmox 7.1 - Can't boot if screen unppluged

DarkArshyn

New Member
Nov 28, 2021
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Hi everyone,

I have a small and disturbing problem. I have an old PC that I use as a hypervisor for my classes to run small VMs remotely.

Previously I had Windows Server 2019 natively installed on it and was running my VMs with VMware Workstation. I was able to boot the PC without any problem, without any device connected (except of course the RJ45 cable), and accessed it via RDP.

I have since decided to switch to Proxmox because it is lighter and I think more adapted to my expectations. The installation went well but I have a problem. If I don't connect a screen, Proxmox doesn't want to start, I don't have access to the web interface at all and except for the local IPv6 address I don't have access to IPv4. However, when I plug in the screen, everything works correctly

I find this problem very annoying as I didn't have it at all under Windows Server. This is not a BIOS problem as I have not made any changes, the problem is with Proxmox itself.

Is there any way to fix this problem please ?

The PC model is : HP EliteDesk 800 G1 USDT

PS: I'm french so sorry for my bad english
 

Dunuin

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Jun 30, 2020
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Doesn't really fix your problem but a workaround might be a dummy plug (costs less than 10€). That will emulate a monitor so your GPU thinks a monitor is connected.
 

DarkArshyn

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Nov 28, 2021
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I have already tried to connect a cable without a monitor behind it, it doesn't boot without it. If there is no solution I guess I'll have to go to something else like ESXi
 

Dunuin

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Jun 30, 2020
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I have already tried to connect a cable without a monitor behind it, it doesn't boot without it. If there is no solution I guess I'll have to go to something else like ESXi
A dummy plug isn't just a cable. It will emulate the communication of the monitor too so the host really thinks there is a monitor connected.
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DarkArshyn

New Member
Nov 28, 2021
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Does it exist in DisplayPort version ? I don't have an HDMI port

I think it comes from Proxmox since I don't have the problem at all with Windows Server, it's probably a story of configuration in a file but I don't know enough about it
 

Dunuin

Famous Member
Jun 30, 2020
6,750
1,571
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Does it exist in DisplayPort version ? I don't have an HDMI port

I think it comes from Proxmox since I don't have the problem at all with Windows Server, it's probably a story of configuration in a file but I don't know enough about it
Yes, dummy plugs are available for all ports. But it is really only a workaround. You really should try to find out first why it isn't working without a monitor attached. I would guess you just got some quirky hardware because PVE is designed to run headless and in general no attached monitor is required.

If you think PVE is the problem you can also try to install a normal Debian 11 (Bullseye) as another workaround and look if it is working without a monitor. If it works you can than install PVE ontop of that Debian. The PVE package will then turn that Debian into a PVE, install all required packages and replace the Debian kernel with the custom PVE kernel (based on the Ubuntu LTS kernel). That is sometimes useful for very old hardware. In that case you are booting the machine like a normal Debian instead of using the proxmox-boot-tool you would get when installing PVE from the PVE ISO. But the debian installer doesn't support ZFS for your system disks. In case you want raid1 you could only use HW raid or mdadm SW raid with etx/xfs/LVM ontop.
 
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DarkArshyn

New Member
Nov 28, 2021
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The problem comes from Linux in general, I installed Debian 11 without anything on it with just an SSH server. Screen plugged in no problem everything works I have SSH access. Screen unplugged nothing works anymore

So I'll see if I can go to ESXi or back to Windows Server, it's a shame
 

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