[pve-devel] [PATCH qemu-server v3 0/6] bugzilla #4225 -- improve handling of unavailable ISOs

[Daniel Herzig]

Fiona Ebner <f.ebner at proxmox.com> writes:

> Am 30.01.25 um 12:31 schrieb Daniel Herzig:
>> This patch series addresses bugzilla entry #4225.
>> 
>> Currently VMs refuse to to start if a configured isofile becomes unavailable,
>> be it a deleted file or an unavailable network storage.
>> 
>> This patch series introduces a new parameter in Drive.pm, called 'essential'.
>> Depending on whether this parameter is set or not, the situation will be handled
>> differently.
>> 
>> If the parameter is set to 0, the configuration will temporarily changed to use
>> 'none' as file for the cd drive, which allows qemu to start up the machine.
>> The configuration is not changed in this process to avoid unexpected behaviour.
>> Instead a log_warn will be issued.
>> 
>> For transition reasons an unset parameter acts like 'required=1'. In this case
>> the startup process will die earlier than currently, if the file is missing or
>> the underlying storage not available.
>
> Since you use the word "transition", is there a plan to change the
> default behavior at some point? IMHO that requires more rationale
> (especially in the backend).
>
I just used this phrasing to underline that the option 'essential', if pro-actively
set to 0, will change current behaviour. Without intervention, people should not
notice any difference to current behaviour with the changes from these
patches. Except the startup error additionaly listing the file, that's
triggering the contact to a non-available network share.

I might have a slight preference to not see ISOs as essential files
after a successful installation indeed, but there certainly are
setups, where it does not make sense to attempt starting up a machine
(or let the attempt fail) without an available ISO attached to the
VM. I'm eg thinking about ephemeral VMs running from live-ISOs or the like.

>> 
>> If a new VM is created from the WebGUI, a corresponding added checkbox
>> is checked by default, but allows for convenient unchecking during setup time,
>> eg for media that is only needed for installation time.
>> 
>> This patch series adds an 'Eject' button to the hardwareview in the WebGUI,
>> which can be used as a convenience shortcut to setting file to 'none' for the
>> cdrom drive.
>> 
>> This series supersedes:
>> https://lore.proxmox.com/pve-devel/20250113085608.99498-1-d.herzig@proxmox.com/