Re: [pve-devel] [PATCH container] fix #3443: setup: clear /etc/machine-id in post-create hook

[Thomas Lamprecht <t.lamprecht@proxmox.com>]

On 26.05.21 12:03, Oguz Bektas wrote:
> On Wed, May 26, 2021 at 12:00:13PM +0200, Thomas Lamprecht wrote:
>> On 26.05.21 11:40, Oguz Bektas wrote:
>>> so without removing the dbus file we don't get a unique machine-id on container
>>> creation, since the templates seem to have a hardcoded id in the dbus path by
>>> default. we can also remove that but then we will have to make sure to do that
>>> for all the relevant templates
>>
>> Yes, but you must check if the dbus one is a symlinlk and if that's the case you
>> must not remove it.
>>
>>>
>>>>
>>>> [0] https://systemd.io/CONTAINER_INTERFACE/
>>>>
>>>>> note that post_create_hook doesn't run for cloned containers so that
>>>>> will need to be handled separately
>>>>>
>>>>
>>>> If you read my post you also read that we must not remove the file in the
>>>> clone case.
>>>
>>>
>>> yes this hook doesn't run at clone so that's fine.
>>>
>>>
>>>>
>>>> We currently always generate a new random MAC-address for all netX devies of
>>>> a CT on clone, that suggests that we always want to truncate in the clone case,
>>>> to ensure that IPv6 SLAAC, among other things, can work OK.
>>>>
>>>> We could add a "unique" param to the clone call, but until now this was never
>>>> requested to be configurable.
>>>
>>> looking at the clone_vm api call i wasn't sure where to modify the file during
>>> clone.
>>>
>>> would it make sense to add this as a config option? we could set this to
>>> "uninitialized" in the container config by default. the "unique" param can then
>>> decide if the machine-id would be copied or truncated at clone.
>>>
>>> i'm open to ideas
>>>
>>
>> no, this would never be a config option as it's a flag for a one time action on
>> clone, not a permanent configuration relevant for the CT.
> 
> sorry i meant here the machine-id as a container config option, and that
> the "unique" param could decide the action taken at clone

The machine-id config is already /etc/machine-id which we have full access to, and
there's no general need to set it to fixed values, can only break things.

The unique flag needs no such thin in the PCT config.