Upgrading the host

Marcin Struzak kunci at struzak.com
Wed Feb 17 15:15:03 UTC 2021

On 2/17/2021 12:23 AM, Michal Privoznik wrote:
> On 2/17/21 2:45 AM, Marcin Struzak wrote:
>> On 2/16/2021 12:51 AM, Michal Privoznik wrote:
>>> On 2/12/21 2:10 AM, Marcin Struzak wrote:
>>> [...]
>>>>  3. Anything else I should worry about or prepare ahead?
>>> Not strictly related to libvirt, but machine types might be problem. 
>>> I guess qemu will be upgraded too and in general the machine type 
>>> you're using for a domain might not be available in upgraded qemu.
>> Correct, it looks like qemu will go from 1.6.2 to 4.2.1...
>>> You can view supported machine types by running 'virsh capabilities' 
>>> with upgraded qemu.
>> machine is pc-i440fx-1.6 in all my domains.  Is there a simple way to 
>> figure out if that's supported in libvirt 6.1.0 (without installing it)?
> It's not libvirt who has say in machine types. Libvirt treats machine 
> type as an opaque string. But I can see that pc-i440fx-1.6 is still 
> available even with the latest QEMU release:
> # /usr/bin/qemu-system-x86_64 -version
> QEMU emulator version 5.2.0
> # virsh capabilities | grep pc-i440fx-1.6
>       <machine maxCpus='255'>pc-i440fx-1.6</machine>
>       <machine maxCpus='255'>pc-i440fx-1.6</machine>
> So you are safe on that front.

Excellent, thank you for checking.

Out of curiosity: what would have been my course of action if that 
particular machine were no longer defined?  I assume: substitute with a 
close match (after figuring out how do determine what counts as "close") 
& hope that the VMs (all Fedoras & Ubuntus) cope & adjust?


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