Public bug reported:

The linux-kvm kernel appears to have a hard-coded limit of 64 configured
CPUs regardless of what is configured on the hypervisor (LXD/QEMU) side.
I believe this includes images in the lxd ubuntu: image remote (
https://cloud-images.ubuntu.com/releases)

This is preventing LXD VMs being configured with more than 64 vCPUs.
This is affecting cloud images with this -kvm kernel pre-installed, so
22.04 LTS and below.

If we are unable to fix this in -kvm, then the request here would be to
re-generate these images to instead use the -generic or -virtual
kernels.


Workaround
---
With that said, the workaround is to simply install either the linux-virtual or 
linux-generic metapackages as they in turn install the generic kernel that does 
not have this limitation.

Repro
---
Configure a 70 cpu VM using the ubuntu:jammy image


$ lxc launch ubuntu:jammy testvm --vm -c limits.memory=12GB -c limits.cpu=70

$ lxc config get testvm limits.cpu
70

$ lxc exec testvm -- nproc
64

** Affects: lxd
     Importance: Undecided
         Status: New

** Affects: linux-meta-kvm (Ubuntu)
     Importance: Undecided
         Status: New

** Also affects: lxd
   Importance: Undecided
       Status: New

-- 
You received this bug notification because you are a member of Ubuntu
Bugs, which is subscribed to Ubuntu.
https://bugs.launchpad.net/bugs/2067777

Title:
  linux-meta-kvm kernel has CPU count capped at 64

To manage notifications about this bug go to:
https://bugs.launchpad.net/lxd/+bug/2067777/+subscriptions


-- 
ubuntu-bugs mailing list
ubuntu-bugs@lists.ubuntu.com
https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs

Reply via email to