The metrics documentation is a bit confusing. There is a ton of useful metrics there, BUT, having installed prometheus exporter in druid, and enabled some monitors in the historical, middlemanager, broker etc configuration files, I have some remarks. • I see far less metrics. Also, the metrics i see are for example of the following form:

# HELP druid_jvm_gc_cpu_created Count of CPU time in Nanoseconds spent on garbage collection. Note: `jvm/gc/cpu` represents the total time over multiple GC cycles; divide by `jvm/gc/count` to get the mean GC time per cycle.
# TYPE druid_jvm_gc_cpu_created gauge
druid_jvm_gc_cpu_created{druid_service="druid/middleManager",gcName="_g1_",} 1.722328820057E9
.........

whereas in the documentation they are like

cpu/segment/time

which is completetely different and in fact I haven’t seen as many useful metrics there. I’m using Druid v28,v29 and v30