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Check the Health of a ksqlDB Server

Check a ksqlDB Server Running in a Native Deployment

If you installed ksqlDB server by using a package manager, like a DEB or RPM, or from an archive, like a TAR or ZIP file, you can check the health of your ksqlDB Server instances by using shell commands.

Use the ps command to check whether the ksqlDB Server process is running:

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ps -aux | grep ksql

Your output should resemble:

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jim       2540  5.2  2.3 8923244 387388 tty2   Sl   07:48   0:33 /usr/lib/jvm/java-8-oracle/bin/java -cp /home/jim/confluent-0.7.1/share/java/monitoring-interceptors/* ...

If the process status of the JVM isn't Sl or Ssl, the ksqlDB server may be down.

Check runtime stats for the ksqlDB server that you're connected to.

  • Run ksql-print-metrics on a server host. The tool connects to a ksqlDB Server that's running on localhost and collects JMX metrics from the server process. Metrics include the number of messages, the total throughput, the throughput distribution, and the error rate. For more information, see Monitoring and Metrics
  • In the ksqlDB CLI or in Confluent Control Center, run SHOW STREAMS or SHOW TABLES, then run DESCRIBE EXTENDED .
  • In the ksqlDB CLI or in Confluent Control Center, run SHOW QUERIES, then run EXPLAIN .

Check a ksqlDB Server by using the REST API

The ksqlDB REST API supports a "server info" request, which you access with a URL like http://<ksqldb-server-url>/info. The /info endpoint returns the ksqlDB Server version, the Apache Kafka® cluster ID, and the service ID of the ksqlDB Server. For more information, see ksqlDB REST API Reference.

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curl -sX GET "http://localhost:8088/info"

Your output should resemble:

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{
    "KsqlServerInfo":{
        "version":"0.7.1",
        "kafkaClusterId":"X5ZV2fjQR1u4zQDLlw62PQ",
        "ksqlServiceId":"default_"
    }
}

Note

This approach doesn't work for non-interactive, or headless, deployments of ksqlDB Server, because a headless deployment doesn't have a REST API server.

ksqlDB Server Running in a Docker Container

If you're running ksqlDB server in a Docker container, run the docker ps or docker-compose ps command, and check that the status of the ksql-server container is Up. Check the health of the process in the container by running docker logs <ksql-server-container-id>.

Page last revised on: 2020-04-29

Last update: 2020-04-29