[systemd-devel] systemd-udevd and services with DefaultDependencies=no

[Thomas HUMMEL]

On 11/25/24 2:50 PM, Andrei Borzenkov wrote:
> On Mon, Nov 25, 2024 at 4:39 PM Thomas HUMMEL <thomas.hummel at pasteur.fr> wrote:
>>
>> Hello,
>>
>> I've got a somehow silly question:
>>
>> Am I right to think that a service unit I wrote meant to format and
>> mount a localdisk at boot having the following properties :
>>
>> Wants=local-fs.target
>> Before=local-fs.target
>>
>> + DefaultDepenencies=no may be racing against udevd in a way the device
>> (/dev/nvme0) would not be there yet ?
>>
> 
> Yes.
> 
>> If so, would adding After=systemd-udevd suffice ?
>>
> 
> No.
> 
> Either invoke your service from within udev rule (SYSTEMD_WANTS or
> even systemctl start), or configure your service with
> 
> Requires=dev-nvme0.device
> After=dev-nvme0.device
> 
> Actually, you probably want to do it even when invoking by udev rules.
> 
> This assumes that /dev/nvme0 is reasonably stable. You may want to use
> some other available /dev/disk/by-... stable alias.

Ok, thanks for your reply.


-- 
Thomas HUMMEL
HPC Group
Institut PASTEUR
Paris, FRANCE