[pve-devel] [PATCH qemu-server v3 2/6] fix #4225: qemuserver: introduce sub eject_nonrequired_isos

[Daniel Herzig]

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

> Am 31.01.25 um 14:58 schrieb Daniel Herzig:
>> Fiona Ebner <f.ebner at proxmox.com> writes:
>> 
>>> Am 31.01.25 um 10:36 schrieb Fiona Ebner:
>>>> Am 30.01.25 um 12:31 schrieb Daniel Herzig:
>>>>> +
>>>>> +    $drive->{essential} = 1 if !defined($drive->{essential});
>>>>
>>>> This should rather be done when parsing the drive.
>>>
>>> Or I guess to avoid (potentially) writing it out for every drive, it
>>> should only be a local variable here and not set in the drive hash.
>> 
>> Thanks, I'll double check on this for v4. But I'd assume the hash to be scoped to
>> `config_to_command` here, or am I missing something?
>> 
>
> But you don't need the modified version in config_to_command() later,
> or? And if yes, that can just check the same way again, i.e. using
> default value if not set. If we want to explicitly set the value, that
> should happen during parsing the drive string. Most of the time it's
> surprising to implicitly modify a passed-in value. Better to either
> avoid that or if really necessary, explicitly mention it in the function
> description.

No, I do not need the modified version of the VM-config later.

What I'm trying to achieve is a more 'forgiving' behaviour in the case
of accidently server-side-deleted iso file/unavailable server (for whatever reason)
attached to a VM. So this is actually aiming at `qm start`, which
implicitly calls `config_to_command` -- without modifying the existing
VM config at all.

If the parameter 'essential' is set to '0', `config_to_command` would --
in case of file unavailability of the iso file -- generate a kvm startup
command that contains "-drive 'if=none,media=cdrom,[...]" instead of
"-drive 'file=$SOME_PATH_TO_ISO,[..]' when we at this point already know
that $SOME_PATH_TO_ISO is unavailable/non-existent.

The VM-config itself is not changed, as an eg nfs-server might come back
at a point in time later and the user might want to do something with the iso
stored there.

If the parameter 'essential' is unset, or set to '1', the die would
happen before `qm start` leads to an invocation of kvm, as it cannot be
expected to lead to a successful action, if $SOME_PATH_TO_ISO is not
reachable. This would be the exact behaviour as we have it now, just not
letting kvm run into this situation, but detect and exit earlier, while
`config_to_commands` iterates over all volumes via `foreach_volume`
anyway before producing the 'final' kvm command.