Process exporter Alert for memory usage of process


I am using “process exporter” from which I get all metrics needed.

link: GitHub - ncabatoff/process-exporter: Prometheus exporter that mines /proc to report on selected processes

I am having hard time for creating alert which will trigger when residential memory reaches 80% of virutal memory.

namedprocess_namegroup_memory_bytes{groupname=“map[:myApp.jar]”, memtype=“resident”, group=“process”, job=“$envirovment”} -
namedprocess_namegroup_memory_bytes{groupname=“map[:myApp.jar]”, memtype=“virtual”, group=“process”, job=“$envirovment”}

Problem is that I can not use metric “namedprocess_namegroup_memory_bytes” two times. How can I achive this?

Thank you.