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Re: qemu crash 100% CPU with Ubuntu10.04 guest (solved)
From: |
Kashyap Chamarthy |
Subject: |
Re: qemu crash 100% CPU with Ubuntu10.04 guest (solved) |
Date: |
Thu, 17 Feb 2022 17:17:09 +0100 |
On Thu, Feb 17, 2022 at 12:07:15PM +1100, Ben Smith wrote:
> Hi All,
Hi,
> I'm cross-posting this from Reddit qemu_kvm, in case it helps in some
> way. I know my setup is ancient and unique; let me know if you would
> like more info.
>
> Symptoms:
> 1. Ubuntu10.04 32-bit guest locks up randomly between 0 and 30 days.
> 2. The console shows a CPU trace dump, nothing else logged on the guest or
> host.
> 3. Host system (Ubuntu20.04) 100% CPU for qemu process.
>
> Solution:
> When using virt-install, always use the "--os-variant" parameter!
> e.g. --os-variant ubuntu10.04
>
> From the man page "--os-variant... Optimize the guest configuration
> for a specific operating system".
> In this case, "optimize" apparently means "stop the crashing".
The "--os-variant" will use virtio devices where applicable, recommended
machine type, guest resources (e.g. CPU, memory, disk size) and other
things that'll improve performance.
> I was deliberately avoiding the option because the VM was already
> performing much better than expected and I didn't want to complicate
> the configuration.
Using it is always recommended when using `virt-install`. The command
`osinfo-query os` will list all the OSes that you can use with
"--os-variant". Note: even if you don't find the latest version of $OS
in `osinfo-query`, just using the most recent version still suffices.
> This was very, very painful to troubleshoot; Involving spinning up 60
> VMs simultaneously, waiting for a failure, changing one parameter,
> repeat. :(
Yikes! Kudos for having the high threshold for frustration.
I think providing a clear reproducer can still be useful. E.g. your
full guest QEMU command-line and your QEMU version. (The
libvirt-generated QEMu log contains the version info.)
--
/kashyap