Missing JVM metrics using prometheus jmx exporter

I am trying to integrate jvm metrics to my akka application. I used prometheus jmx exporter. Instead of using the whole app and running it as java agent, I used only the exporter and integrated to my existing prometheus registry

import io.prometheus.jmx.JmxCollector

val jmxCollector: JmxCollector = new JmxCollector(getClass.getResourceAsStream("jmx-config.yaml"))
jmxCollector.register(prometheusRegistry)

I am able to see the metrics but few metrics starting with prefix jvm are missing compared to other applications which are running the exporter as java agent. Like thread metrics which are missing

# HELP jvm_threads_state Current count of threads by state
# TYPE jvm_threads_state gauge
jvm_threads_state{state="TERMINATED",} 0.0
jvm_threads_state{state="RUNNABLE",} 10.0
jvm_threads_state{state="TIMED_WAITING",} 11.0
jvm_threads_state{state="WAITING",} 37.0
jvm_threads_state{state="NEW",} 0.0
jvm_threads_state{state="BLOCKED",} 0.0

My metrics config is bare minimum and looks like this in both the applications

---
startDelaySeconds: 10
ssl: false
lowercaseOutputName: false
lowercaseOutputLabelNames: false

Could you please help me understand what could be the difference that is causing this problem.

This is the expected behaviour

This exporter is intended to be run as a Java Agent, exposing a HTTP server and serving metrics of the local JVM. It can be also run as a standalone HTTP server and scrape remote JMX targets, but this has various disadvantages, such as being harder to configure and being unable to expose process metrics (e.g., memory and CPU usage).

The "being unable to expose process metrics" is a subtle reference to the jvm_* metrics like

• jvm_classes_loaded
• jvm_classes_loaded_total
• jvm_threads_current
• jvm_threads_daemon
• jvm_memory_used_bytes (There is no such thing as jvm_memory_bytes_used in client_java)
• jvm_memory_pool_used_bytes (There is no such thing as jvm_memory_pool_bytes_used in client_java)
• jvm_memory_pool_allocated_bytes_total (There is no such thing as jvm_memory_pool_allocated_bytes_created in client_java)
• jvm_memory_pool_committed_bytes (There is no such thing as jvm_memory_pool_bytes_committed in client_java )
• jvm_memory_pool_init_bytes (There is no such thing asjvm_memory_pool_bytes_init in client_java)
• jvm_memory_pool_max_bytes (There is no such thing asjvm_memory_pool_bytes_max in client_java)
• (There is no such thing asjvm_memory_pool_bytes_used in client_java)
• jvm_memory_pool_collection_committed_bytes
• jvm_memory_pool_collection_init_bytes
• jvm_memory_pool_collection_max_bytes
• jvm_memory_pool_collection_used_bytes
• jvm_threads_deadlocked
• jvm_threads_deadlocked_monitor
• jvm_threads_peak
• jvm_threads_started_total
• jvm_threads_state

All those metrics are still available when using the httpserver but under a different name that matches the JMX MBean where the actual value is.

For example, the equivalent to jvm_classes_loaded / jvm_classes_loaded_total in javagent is java_lang_ClassLoading_LoadedClassCount.

And the equivalent to jvm_threads_current in httpserver is java_lang_Threading_ThreadCount.

Here is a table with some equivalences

See 14, 15 for more information