# Cassandra > Monitor Apache Cassandra metrics with OpenTelemetry and Last9 Source: https://last9.io/docs/integrations/databases/cassandra/ Use OpenTelemetry to monitor your Apache Cassandra cluster and send telemetry data to Last9. This integration runs the `opentelemetry-jmx-metrics` JAR as a service alongside Cassandra to collect JMX metrics, which are forwarded to the OTel Collector via OTLP. Read the [sample configuration](https://github.com/last9/opentelemetry-examples/tree/main/otel-collector/cassandra) for more details. ## Prerequisites - Apache Cassandra 3.x or 4.x installed and running - Java 11+ installed on the host (required by the JMX metrics JAR) - JMX enabled in Cassandra (enabled by default on port 7199) - Last9 account with integration credentials ## Verify JMX Access Cassandra enables JMX on port 7199 by default. Verify it is reachable: ```bash ss -tlnp | grep 7199 ``` :::note If Cassandra JMX authentication is enabled, add `username` and `password` fields to the `jmx` receiver configuration. ::: ## Install OpenTelemetry Collector **AMD64** ```bash sudo apt-get update && sudo apt-get install -y wget wget https://github.com/open-telemetry/opentelemetry-collector-releases/releases/download/v0.144.0/otelcol-contrib_0.144.0_linux_amd64.deb sudo dpkg -i otelcol-contrib_0.144.0_linux_amd64.deb ``` **ARM64** ```bash sudo apt-get update && sudo apt-get install -y wget wget https://github.com/open-telemetry/opentelemetry-collector-releases/releases/download/v0.144.0/otelcol-contrib_0.144.0_linux_arm64.deb sudo dpkg -i otelcol-contrib_0.144.0_linux_arm64.deb ``` **RPM (RHEL/CentOS)** ```bash wget https://github.com/open-telemetry/opentelemetry-collector-releases/releases/download/v0.144.0/otelcol-contrib_0.144.0_linux_amd64.rpm sudo rpm -ivh otelcol-contrib_0.144.0_linux_amd64.rpm ``` ## Download JMX Metrics JAR The JMX receiver requires a metrics collection JAR: ```bash sudo mkdir -p /opt sudo wget -O /opt/opentelemetry-jmx-metrics.jar \ https://github.com/open-telemetry/opentelemetry-java-contrib/releases/download/v1.43.0/opentelemetry-jmx-metrics.jar ``` ## Configure JMX Metrics Collection 1. **Create the JMX config** Create `/etc/otelcol-contrib/jmx-config.properties`: ```properties otel.exporter.otlp.endpoint = http://localhost:4317 otel.jmx.interval.milliseconds = 60000 otel.jmx.service.url = service:jmx:rmi:///jndi/rmi://localhost:7199/jmxrmi otel.jmx.target.system = cassandra otel.metrics.exporter = otlp ``` If JMX authentication is enabled, add: ```properties otel.jmx.username = otel.jmx.password = ``` 2. **Run the JMX metrics JAR as a service** Create `/etc/systemd/system/cassandra-jmx-metrics.service`: ```ini [Unit] Description=Cassandra JMX Metrics Collector After=cassandra.service [Service] ExecStart=java -jar /opt/opentelemetry-jmx-metrics.jar -config /etc/otelcol-contrib/jmx-config.properties Restart=always RestartSec=10 [Install] WantedBy=multi-user.target ``` ```bash sudo systemctl daemon-reload sudo systemctl enable --now cassandra-jmx-metrics ``` 3. **Create the Collector Configuration** Create `/etc/otelcol-contrib/config.yaml`: ```yaml receivers: otlp: protocols: grpc: endpoint: 0.0.0.0:4317 hostmetrics: collection_interval: 60s scrapers: cpu: metrics: system.cpu.logical.count: enabled: true memory: metrics: system.memory.utilization: enabled: true system.memory.limit: enabled: true load: disk: filesystem: metrics: system.filesystem.utilization: enabled: true network: paging: processors: batch: timeout: 5s send_batch_size: 10000 send_batch_max_size: 10000 resourcedetection/system: detectors: ["system"] system: hostname_sources: ["os"] transform/add_db_system: metric_statements: - context: datapoint statements: - set(attributes["host.name"], resource.attributes["host.name"]) - set(attributes["db.system"], "cassandra") exporters: otlp/last9: endpoint: "{{ .Logs.WriteURL }}" headers: "Authorization": "{{ .Logs.AuthValue }}" service: pipelines: metrics/jmx: receivers: [otlp] processors: [batch, transform/add_db_system] exporters: [otlp/last9] metrics/host: receivers: [hostmetrics] processors: [batch, resourcedetection/system, transform/add_db_system] exporters: [otlp/last9] ``` Replace `endpoint` and `Authorization` with your Last9 credentials from the [Integrations page](https://app.last9.io/integrations). 4. **Start the Collector** ```bash sudo systemctl enable --now otelcol-contrib ``` ## Nodetool Metrics (Extended Collection) JMX covers per-table latency and request counts, but some cluster-level metrics are only accessible via `nodetool`. The integration includes a nodetool exporter that runs alongside Cassandra and exposes these additional metrics on port 9500. **Bare-metal setup** — create `/etc/systemd/system/cassandra-nodetool-exporter.service`: ```ini [Unit] Description=Cassandra Nodetool Prometheus Exporter After=cassandra.service [Service] Environment=CASSANDRA_HOST=localhost Environment=CASSANDRA_JMX_PORT=7199 Environment=EXPORTER_PORT=9500 ExecStart=python3 /opt/nodetool-exporter.py Restart=always RestartSec=15 [Install] WantedBy=multi-user.target ``` Download the exporter script: ```bash sudo wget -O /opt/nodetool-exporter.py \ https://raw.githubusercontent.com/last9/opentelemetry-examples/main/otel-collector/cassandra/nodetool-exporter.py sudo systemctl daemon-reload && sudo systemctl enable --now cassandra-nodetool-exporter ``` Add the following receiver and pipeline to your OTel Collector config: ```yaml receivers: prometheus/nodetool: config: scrape_configs: - job_name: cassandra_nodetool scrape_interval: 60s static_configs: - targets: ["localhost:9500"] service: pipelines: metrics/nodetool: receivers: [prometheus/nodetool] processors: [batch, transform/add_db_system] exporters: [otlp/last9] ``` ## Metrics Collected | Metric category | Examples | | ------------------ | ------------------------------------------------------------------------------------------------------------------- | | Read/write latency | `cassandra_client_request_read_latency_50p_microseconds`, `cassandra_client_request_write_latency_99p_microseconds` | | Request counts | `cassandra_client_request_count_total`, `cassandra_client_request_error_count_total` | | Compaction | `cassandra_compaction_tasks_completed_total`, `cassandra_compaction_tasks_pending` | | Storage | `cassandra_storage_load_count_bytes`, `cassandra_storage_hints_count_total` | | Cluster topology | `cassandra_nodetool_nodes_up`, `cassandra_nodetool_nodes_down` | | Thread pools | `cassandra_nodetool_thread_pool_pending`, `cassandra_nodetool_thread_pool_blocked` | | Heap & cache | `cassandra_nodetool_heap_used_mb`, `cassandra_nodetool_key_cache_hit_rate` | | System | CPU, memory, disk, network via `hostmetrics` | ## Verification 1. **Check Collector Status** ```bash sudo systemctl status otelcol-contrib ``` 2. **View Collector Logs** ```bash sudo journalctl -u otelcol-contrib -f ``` 3. **Verify Metrics in Last9** Log into your Last9 account and check that Cassandra metrics are being received. Look for metric names starting with `cassandra.`. --- ## Troubleshooting - **JMX connection refused** ```bash # Verify JMX port is listening ss -tlnp | grep 7199 # Check Cassandra is running nodetool status # Test JMX connectivity java -jar /opt/opentelemetry-jmx-metrics.jar \ -targetSystem cassandra \ -endpoint service:jmx:rmi:///jndi/rmi://localhost:7199/jmxrmi ``` - **`ClassNotFoundException` or JAR issues** ```bash # Verify Java is installed java -version # Check JAR is present and readable ls -la /opt/opentelemetry-jmx-metrics.jar ``` - **Collector not starting** ```bash sudo journalctl -u otelcol-contrib -n 100 --no-pager ``` Please get in touch with us on [Discord](https://discord.com/invite/Q3p2EEucx9) or [Email](mailto:support@last9.io) if you have any questions.