[SOLVED] Issue with Ubuntu VM Setup on Proxmox VE with 4 Core CPU

[Sena]

I'm running Proxmox VE on a PC with 4 physical cores.
When I try to create an Ubuntu virtual machine using all 4 cores, it stops with errors during the setup process.
I would appreciate if someone could advise me on how to resolve this issue.

 

[UdoB]

When I try to create an Ubuntu virtual machine using all 4 cores, it stops with errors during the setup process.

That's surprising. Some weeks ago I tested a VM with many more virtual CPUs than the host has. (As a proof-of-concept, not to be used in production.)

Try to setup that VM with only two CPUs. You can increase the number of cores (and modify nearly every other aspect of the virtual hardware) once the VM is running successfully.

Without posting an actual error message (and some description of your setup) you can not expect more specific hints...

 

[Sena]

Thank you for your reply.
How can I extract the logs?
Here is a screenshot of the error that occurred.
By the way, it works with 3 cores.

 

[david_tao]

May you can check does your PC is really have 4 cores. or it's 2 cores only and use Hyper-thread let it seems as 4 cores!

 

[UdoB]

Here is a screenshot of the error that occurred.

I've never seen that one.

Next try: which CPU type did you choose? "Host"? Try with "x86-64-v2" or "kvm64". (The most of my VMs use the first one.)

Please post the output of qm config <yourvmid> too.

 

[Sena]

May you can check does your PC is really have 4 cores. or it's 2 cores only and use Hyper-thread let it seems as 4 cores!

Since it's an Intel Core i5-7500, I probably have actual 4 cores.
Also, it worked normally with a 3-core configuration.

 

[Sena]

Please post the output of qm config <yourvmid> too.

boot: order=scsi0;ide2;net0
cores: 4
cpu: x86-64-v2-AES
ide2: local:iso/ubuntu-24.04.2-live-server-amd64.iso,media=cdrom,size=3137758K
memory: 1024
meta: creation-qemu=9.0.2,ctime=1742218915
name: goldenraito
net0: virtio=BC:24:11:53:AE:F4,bridge=vmbr0,firewall=1
numa: 0
ostype: l26
scsi0: local-lvm:vm-101-disk-0,iothread=1,size=32G
scsihw: virtio-scsi-single
smbios1: uuid=7d51131d-bb69-47c3-ba50-6415afa4d4a9
sockets: 1
vmgenid: 3aa02843-31fd-4366-849f-27dcb76cbb1e

 

[Sena]

Next try: which CPU type did you choose? "Host"? Try with "x86-64-v2" or "kvm64". (The most of my VMs use the first one.)

I tried all three types, but they all fail at the same point during setup.

 

[gfngfn256]

memory: 1024

Increase that RAM to at least 2048 (2GB) or more.

As per the official documentation:

The recommended minimal system requirements for this tutorial are:

• RAM: 2 GiB or more

 

[UdoB]

If increasing Ram does not help: please verify the checksum of the downloaded .iso - the SHA256 is in https://releases.ubuntu.com/noble/SHA256SUMS

 

[MarkusKo]

May you can check does your PC is really have 4 cores. or it's 2 cores only and use Hyper-thread let it seems as 4 cores!

according to the intel specs page this cpu does not support hyperthreading, it has 4 cores / 4 threads

 

[guruevi]

What does the installation error report say?

 

[Sena]

If increasing Ram does not help: please verify the checksum of the downloaded .iso - the SHA256 is in https://releases.ubuntu.com/noble/SHA256SUMS

There were no problems with the checksum. Additionally, when using the same ISO file with 3 cores instead of 4 cores, it operates normally.

 

[Sena]

What does the installation error report say?

Where should I look?Is this what you mean?

 

[guruevi]

That’s just a screenshot that shows part of dmesg.

Full dmesg output may tell more
Logs should be in /var/log/installer

You can switch to a terminal with ctrl-alt-f1

 

[gfngfn256]

You seem to avoid discussing/reporting increasing the VM's RAM - as I have suggested above, based on the official recommendation.

 

[Sena]

You seem to avoid discussing/reporting increasing the VM's RAM - as I have suggested above, based on the official recommendation.

Even after increasing the memory to 2GB, the error shown in the image occurs after rebooting following installation. This is the same error that appeared when the memory was 1GB, which forced a reboot.

 

[guruevi]

That is what happens after the system tries to restart, it can't eject the CDROM because it isn't a physical thing, you have to manually remove the CDROM, then press enter. That's part of the normal install procedure, if you got there, typically that means the install is complete.

 

[Sena]

Even after increasing the memory to 2GB, the error shown in the image occurs after rebooting following installation. This is the same error that appeared when the memory was 1GB, which forced a reboot.

Until now, it wouldn't work after restarting, but now it's working.It seems the cause was that the memory was 1GB.Is there no way to start Ubuntu with 1GB of memory?

 

[Sena]

For now, I'm grateful that it's starting up with 4 cores!
Thank you everyone.