Isolator Java Agent

The isolator Java agent starts one or more JMX Exporter Java agent jars in isolated classloaders. Use it only when you need multiple independent exporter instances in the same JVM.

Artifacts

Download both jars from the 1.7.0 release:

• jmx_prometheus_isolator_javaagent-1.7.0.jar
• jmx_prometheus_javaagent-1.7.0.jar

Argument format

-javaagent:jmx_prometheus_isolator_javaagent-1.7.0.jar=/path/to/exporter1.jar=agentArgs1,/path/to/exporter2.jar=agentArgs2

Each comma-separated item contains the exporter jar path, an equals sign, and the Java agent arguments for that exporter.

Example

java -javaagent:jmx_prometheus_isolator_javaagent-1.7.0.jar=jmx_prometheus_javaagent-1.7.0.jar=9404:exporter.yaml,jmx_prometheus_javaagent-1.7.0.jar=9405:exporter2.yaml -jar your-application.jar

Lifecycle and errors

The isolator agent starts each exporter through an isolated classloader on a daemon startup thread. Startup waits for the implementation timeout and logs a warning if the thread is still alive. A missing, empty, or malformed isolator argument fails startup.

Logging backend

The isolator and nested JMX Exporter agents use Java Util Logging (JUL) by default. Set -Djmx.prometheus.exporter.logging.backend=native or JMX_PROMETHEUS_EXPORTER_LOGGING_BACKEND=native to avoid initializing or configuring the application's JUL system during startup. Native logging writes INFO, WARN, and ERROR messages to standard error. The system property takes precedence, and the selected backend is fixed when each logger is first created. JUL is process-wide and may initialize the application's configured LogManager during agent startup.