rJMX-Exporter

A high-performance JMX metrics exporter for Prometheus, written in Rust. Collects JMX metrics via Jolokia without requiring a JVM.

Installation

From Source (Recommended)

git clone https://github.com/jsoonworld/rJMX-Exporter.git
cd rJMX-Exporter
cargo build --release
# Binary at ./target/release/rjmx-exporter

Docker

docker pull ghcr.io/jsoonworld/rjmx-exporter:latest
# or build locally
docker build -t rjmx-exporter .

Docker Compose (Full Stack Demo)

git clone https://github.com/jsoonworld/rJMX-Exporter.git
cd rJMX-Exporter
docker compose up -d
# Java App: http://localhost:8778/jolokia
# Metrics:  http://localhost:9090/metrics
# Prometheus: http://localhost:9091

Why rJMX-Exporter?

The official jmx_exporter requires a JVM and either shares your app's heap (javaagent) or adds ~50MB overhead (standalone). rJMX-Exporter runs as a native binary sidecar with zero impact on your application.

Metric	jmx_exporter	rJMX-Exporter
Memory	~50MB+	<10MB
Startup	2-5s	<100ms
JVM Required	Yes	No
App Impact	Shares GC/Heap	None

Limitations

Be aware of these trade-offs:

• Requires Jolokia - Your JVM needs the Jolokia agent for HTTP/JSON access to JMX
• No direct RMI - Cannot connect to JMX via RMI protocol (use Jolokia instead)
• Newer project - Less battle-tested than jmx_exporter in production environments

Quick Start

1. Add Jolokia to your JVM:

java -javaagent:jolokia-jvm-1.7.2.jar=port=8778,host=0.0.0.0 -jar your-app.jar

2. Create config.yaml:

jolokia:
  url: "http://localhost:8778/jolokia"

server:
  port: 9090

rules:
  - pattern: 'java.lang<type=Memory><HeapMemoryUsage>(\w+)'
    name: "jvm_memory_heap_$1_bytes"
    type: gauge

3. Run:

./rjmx-exporter -c config.yaml
curl http://localhost:9090/metrics

Documentation

Document	Description
Configuration	Full config reference
Migration Guide	Migrate from jmx_exporter
CLI Reference	Command-line options
Design Doc	Architecture and design decisions

Architecture

JVM App (Jolokia) --HTTP/JSON--> rJMX-Exporter --/metrics--> Prometheus

Contributing

Contributions welcome! Please read CONTRIBUTING.md.

# Development
cargo test          # Run tests
cargo clippy        # Lint
cargo fmt           # Format

# PRs target `develop` branch, not `main`

License

Dual-licensed under MIT or Apache-2.0.

Acknowledgments

• jmx_exporter - The original Java implementation
• Jolokia - JMX-HTTP bridge
• Tokio & Axum - Async Rust ecosystem