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Running custom Connectors

You can deploy your custom Connector in your Helm Kubernetes cluster along with Connectors Bundle.

The default runtime loads Connectors from classpath via SPI. For the custom Connectors, there is a dedicated folder inside a Connectors Docker image /opt/custom; any JAR placed here is included in the classpath.

This page explains how to put your custom Connector into the /opt/custom.

Prerequisites​

Start with creating and building a 'fat' JAR (JAR with dependencies) of your custom Connector. For the purpose of this guide, let's consider the custom Connector name custom-connector-0.0.1-with-dependencies.jar.

Then, place the JAR somewhere accessible by Helm during installation. For the purpose of this guide, let's consider the path to the Connector is https://my.host:80/dist/custom-connector-0.0.1-with-dependencies.jar.

Modify Connectors config​

Modify the values.yaml file in the Camunda Helm charts repository:

connectors:
  initContainers:
    - name: init-script-downloader
      image: appropriate/curl
      args:
        - "-o"
        - "/opt/custom/custom-connector-0.0.1-with-dependencies.jar"
        - "https://my.host:80/dist/custom-connector-0.0.1-with-dependencies.jar"
      volumeMounts:
        - name: init-script
          mountPath: /opt/custom

  extraVolumes:
    - name: init-script
      emptyDir: {}

  extraVolumeMounts:
    - mountPath: /opt/custom/custom-connector-0.0.1-with-dependencies.jar
      name: init-script
      subPath: custom-connector-0.0.1-with-dependencies.jar

After modification, you can run helm install ... as usual. These changes copy a custom Connector JAR before the Connector runtime starts.

The appropriate/curl is not the only image option for the initContainers. There are other curl-based alternatives you can use; for example, curlimages/curl. Check args configuration with your vendor.

Troubleshooting​

If your custom Connector won't start, consider the following troubleshooting steps:

  • Make sure your Connector is present in the /opt/custom folder in the pod.
  • Make sure the original Connector and the one in /opt/custom are the same. Usually, file size check is sufficient, but in some cases you may want to have a checksum comparison.