Re: Wait for interface existence?

[Joerg Sonnenberger <joerg%bec.de@localhost>]

On Mon, Aug 28, 2023 at 01:14:52PM -0400, Mouse wrote:
> >> I find myself wanting a tool that waits until a certain set of
> >> network interfaces exists.  (I want this so I can, for example, have
> >> a boot-time script wait until tap0 and tap1 both exist, then do
> >> whatever is appropriate.)
> > ifwatchd?
> 
> Related, but I don't see any way to get what I want out of ifwatchd
> without significant additional tooling around it.
> 
> ifwatchd can run something when tap0 is created and when tap1 is
> created, but unless I've missed something it would take additional
> tooling to notice that both those events have happened and shut down
> the ifwatchd process.

Well, the script I would be using just rechecks if both interfaces exist
and continues doing whatever is necessary in that case. Given that e.g.
tap0 can appear, disappear again, tap1 appear and then tap0 reappear,
anything else sounds like a lot of magic for something that is far
easier handled by just checking for the existance of both.

Joerg