Re: [PATCH v2] build: add After=network-pre.target to service files

[Denis Kenzior <denkenz@gmail.com>]

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Hi Alvin,

On 1/22/21 8:41 AM, Alvin Šipraga wrote:
> systemd specifies a special passive target unit 'network-pre.target'
> which may be pulled in by services that want to run before any network
> interface is brought up or configured. Correspondingly, network
> management services such as iwd and ead should specify
> After=network-pre.target to ensure a proper ordering with respect to
> this special target. For more information on network-pre.target, see
> systemd.special(7).
> 
> Two examples to explain the rationale of this change:
> 
> 1. On one of our embedded systems running iwd, a oneshot service is
>     run on startup to configure - among other things - the MAC address of
>     the wireless network interface based on some data in an EEPROM.
>     Following the systemd documentation, the oneshot service specifies:
> 
>          Before=network-pre.target
>          Wants=network-pre.target
> 
>     ... to ensure that it is run before any network management software
>     starts. In practice, before this change, iwd was starting up and
>     connecting to an AP before the service had finished. iwd would then
>     get kicked off by the AP when the MAC address got changed. By
>     specifying After=network-pre.target, systemd will take care to avoid
>     this situation.
> 
> 2. An administrator may wish to use network-pre.target to ensure
>     firewall rules are applied before any network management software is
>     started. This use-case is described in the systemd documentation[1].
>     Since iwd can be used for IP configuration, it should also respect
>     the After=network-pre.target convention.
> 
> Note that network-pre.target is a passive unit that is only pulled in if
> another unit specifies e.g. Wants=network-pre.target. If no such unit
> exists, this change will have no effect on the order in which systemd
> starts iwd or ead.
> 
> [1] https://www.freedesktop.org/wiki/Software/systemd/NetworkTarget/
> ---
>   src/iwd.service.in   | 1 +
>   wired/ead.service.in | 1 +
>   2 files changed, 2 insertions(+)
> 

Applied, thanks.

Regards,
-Denis