Function at_boot 

pub fn at_boot(
    name: &str,
    what: &str,
    script: &str,
    trigger: Trigger,
    after: &[&str],
) -> String

script saved as /etc/isoloom/<name>.sh and run now and again as trigger says, by a systemd service (isoloom-<name>), what saying what it does.

after: the other such scripts it runs after at boot (routes through a trunk’s interface after the trunks).

Without systemd (OpenRC: Alpine), it runs from /etc/local.d at boot instead.

The script always succeeds (a route whose link isn’t up yet, a VLAN interface already there): an interface hook failing would fail the interface’s bring-up. It runs again at the next boot or link change.