Execute script when failover happens?

bmaster

Is it somehow possible to execute a script when a slave node "promotes" to master? This would be great because right now if one machine fails, there's the possibility nobody notices it.

jimp

Sure, this is possible on 1.2.3 and 2.0

2.0 already has the code in /etc/devd.conf to do this, but you can edit it into the end of /etc/devd.conf (and either restart devd or reboot, rebooting is probably easier):

# CARP notify hooks. This will call carpup/carpdown with the
# interface (carp0, carp1) as the first parameter.
notify 100 {
    match "system"          "IFNET";
    match "type"            "LINK_UP";
    match "subsystem"           "carp";
    action "/etc/rc.carpmaster $subsystem";
};

notify 100 {
    match "system"          "IFNET";
    match "type"            "LINK_DOWN";
    match "subsystem"           "carp";
    action "/etc/rc.carpbackup $subsystem";
};

And then it will exec /etc/rc.carpmaster when it becomes a master, and /etc/rc.carpbackup when it becomes a backup. You can change the script names if you want.

2.0 can notify by e-mail or growl when such a switch happens.

bmaster

Thank you, that seems to do the trick!