Ah, that's now what we need, nice for the script!

The file /usr/local/etc/devd/carp.conf :

You can directly use variables in the action to pass interface and state with $subsystem and $type

For all CARP external documentation, I think I've found the threshold where information is outdated in that man page:

According carp(4) (man carp) examples section, the name has changed.

@dereckson I first tried to redefine the devd rule by matching specific IFNET event types such as LINK_UP, LINK_DOWN, UP and DOWN, but none of them were triggered during CARP state changes in my tests.

A dedicated devd file was placed in /usr/local/etc/devd because this directory is usually used for custom configurations added by administrators, while /etc/devd contains the default system rules from FreeBSD. It makes the setup cleaner, avoids mixing custom logic with system configuration, and makes future maintenance or upgrades easier.

Proof of concept to call OVH API from Python to define MAC address to router-002/003.

OVH API credentials published to apps/network/carp-hyper-001-switch path,
under application_key, application_secret, consumer_key keys.

If we trigger the script through devd, we can provide a .conf configuration file in /usr/local/etc/devd.