OpenNMS Prometheus Alertmanager Bridge

A Spring Boot 3.5 application that bridges OpenNMS alarms to Prometheus Alertmanager, enabling unified alerting and visualization through Grafana.

Overview

This application subscribes to OpenNMS Kafka topics (alarms and nodes) and forwards alarm data to Prometheus Alertmanager. It enriches alerts with full OpenNMS node information, including custom metadata.

Features

• Kafka Consumer: Subscribes to OpenNMS alarms and nodes topics
• Protobuf Decoding: Parses GPB-encoded messages from OpenNMS
• Node Enrichment: Caches node data including custom metadata
• Alertmanager Integration: Forwards alarms via Alertmanager API v2
• Automatic Resend: Periodically resends active alerts
• Metrics Export: Prometheus metrics at /actuator/prometheus

Quick Start

# Build
make oci

# Run with Docker Compose (full stack)
cd example/docker
docker compose up -d

Configuration

Key environment variables:

Variable	Description	Default
KAFKA_BOOTSTRAP_SERVERS	Kafka brokers	localhost:9092
ALERTMANAGER_URL	Alertmanager URL	http://localhost:9093
OPENNMS_URL	OpenNMS URL	http://localhost:8980/opennms

Alert Labels

Label	Source
alertname	Derived from UEI
severity	OpenNMS severity
node_id, node_label	Node info
opennms_categories	Node categories
opennms_meta_*	Custom metadata

API Endpoints

• GET /api/v1/bridge/status - Bridge status
• GET /api/v1/bridge/alarms - Active alarms
• GET /api/v1/bridge/nodes - Cached nodes
• POST /api/v1/bridge/alarms/resend - Force resend

Create and publish a new release

To make a release the following steps are required:

1. Set the Maven project version without -SNAPSHOT
2. Make a version tag with git
3. Set a new SNAPSHOT version in the main branch
4. Publish a release

To help you with these steps you can run a make goal make release. It requires a version number you want to release. As an example the current main branch has 0.0.2-SNAPSHOT and you want to release 0.0.2 you need to run

make release RELEASE_VERSION=0.0.2

The 0.0.2 version is set with the git tag v0.0.2. It will automatically set the main branch to 0.0.3-SNAPSHOT for the next iteration. All changes stay in your local repository. When you want to publish the new released version you need to run

git push                # Push the main branch with the new -SNAPSHOT version
git push origin v0.0.2  # Push the release tag which triggers the build which publishes artifacts.

License

Apache License 2.0