Global alerting method for global deadman

Kapacitor configuration file allows to activate a global deadman switch, which I assume should alert when a monitored server is down (no more metrics received).
But how to configure the global alerting system? I didn’t find any log ability as log method for AlertNodes.
HTTPPost has no global parameter.
From configuration page, it seems an [alert] section should help but no example is provided.
Thanks for any input