[pve-devel] [PATCH cluster/docs/manager/network/proxmox{, -ve-rs, -firewall, -perl-rs} 00/52] Add SDN Fabrics

[Stefan Hanreich]

On 4/3/25 16:20, Friedrich Weber wrote:
> On 03/04/2025 16:03, Stefan Hanreich wrote:
>>
>>
>> On 4/3/25 15:44, Friedrich Weber wrote:
>>>>> - when removing a fabric, the IP addresses defined on the interfaces
>>>>> remain until the next reboot. I guess the reason is that ifupdown2
>>>>> doesn't remove IP addresses when the corresponding stanza vanishes. Not
>>>>> sure if this can be easily fixed -- if not, maybe this would be worth a
>>>>> note in the docs?
>>>>
>>>> Umm, I think `ifreload -a` should remove all the addresses? At least it
>>>> works on my machine :)
>>>>
>>>> But I'll check again.
>>>
>>> I took a closer look -- seems I can only reproduce this if
>>> /etc/network/interfaces contains an empty `iface INTERFACE inet manual`
>>> stanza for the interface. Without such a stanza, the IP address is
>>> removed correctly.
>>
>> `manual` means, that IP addresses are configured manually by the user,
>> so if ifupdown2 encounters an address configured on that interface it
>> won't remove it, since you're telling it with manual that it isn't
>> responsible for managing addresses on that interface. So I'd say that's
>> expected with that line?
> 
> Hmm, the explanation makes sense, but seems like our installer
> automatically adds [1] an `iface INTERFACE inet manual` stanza for all
> "unused" interfaces? So users may run into this (admittedly minor) issue
> if they used interfaces that were already present at installation time
> for a fabric, and then remove that fabric.
> 
> [1]
> https://git.proxmox.com/?p=pve-installer.git;a=blob;f=Proxmox/Install.pm;h=57fd899;hb=95f2bc3ee#l1097

That's a very valid point - and maybe not even that unlikely in
practice. We should either document this, or find a way around it. I'll
try to think of a solution, but this one is probably a bit tricky to
tackle with how the config generation currently works.