We have some IoT devices installed on an external area (think of a retail chain which for each shop has installed our IoT devices).
And our main priority is to get UPTIME status for each of them.
We investigate about Heartbeat, but seems that Heartbeat is responsible to collect information via HTTP, TCP or ICMP.
Unfortunately no one of the above cases fit our needs because the IoT device is behind an firewall and not accessible from outside, then we need to SEND HEARTBEAT SIGNAL from IoT device to Elastic cluster (the opposite how heartbeat works).
How we can do that?
Also we saw and investigate about APM (for nodejs in our case) and we found a lot of usefull information about LOGS and METRICS but nothing about UPTIME; do you think that APM should also care about UPTIME metric?