On our side we have some alerting in the case of your node not reporting to us within a few hours. In the event of not seeing your node down for a couple of days - we will inform you via mail.

In terms of internal monitoring you could add alerts to see if the instances are responding and also checking if ports are responding, the API (443) and Cassandra (7000) on the app instance.

Example - using nc to check if besu is online:

nc -n -v -z 3.125.144.198 7000
Ncat: Version 7.70 ( https://nmap.org/ncat )
Ncat: Connected to 3.125.144.198:7000.
Ncat: 0 bytes sent, 0 bytes received in 0.02 seconds.