How to know when br0 is created

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1

I’m trying to write a systemd unit to start an application to run in the background. Due to a couple of restrictions, I have to run this in a network namespace with a Virtual Ethernet connecting the namespace to the root, where it’s added to br0. I need to ensure this unit doesn’t attempt to add it before br0 is created.
What current unit(s) can I use for the After= checks to ensure this.

Cheers.

2

Answering my own question. I later realised that I also need the be able to run the service under a “normal” user. So following how I have other user services set up, I think this should do what I need:

After=systemd-user-sessions.service

Cheers.