I'm currently working with spark-jobserver, and when the spark-jobserver goes down my app just stop working but I don't get notified
There is a health check to spark-jobserver?
If the service goes down, it also wouldn't notify. Therefore, there isn't a built-in option for this.
Ideally you'd use external monitoring like Prometheus Blackbox exporter, Nagios, or simply cron to curl/netcat your service.