Metric in Prometheus - tracking the number of running instances?

Question

Analytics

There is a gauge metric instance_liveness {instanceId="{{random_id}}"}. I would like to display on the grafana, in fact, the number of "live" instances, the metric is pushed every 5 seconds.

At the moment I'm plotting this: count(count_over_time(sqsMessageHandler_service_liveness[10m]) > 0) by (env,instanceId).

It looks somehow crooked, given that the idea itself with constantly different instanceIds is row violence, but I didn’t come up with any other solution here. Maybe someone has already solved this problem?