title: How to pass mount a single file as volume to KubernetesPodOperator?
body: <p>I have a docker image that expects a mounted JSON credentials file on startup. The container is started through a command like:</p>
  
  <p><code>docker run -v [CREDENTIALS_FILE]:/credentials.json image_name</code></p>
  
  <p>This image lives on Google Container Registry and I'd like to start it in a Cloud Composer dag using the KubernetesPodOperator.</p>
  
  <p>Is there a way mount a single file through the KubernetesPodOperator? Ideally, this file would be hosted at a Cloud Storage location. I read that there is a volume/volume_mount options but it seems like a heavy-lift to pass a single file through -- hoping there was another option I'm overlooking.</p>
  
  <pre><code>KubernetesPodOperator(namespace='default',
                        image="gcr.io/image_name,
                        name="start-container-image",
                        task_id="start-container-image",
                        volume=[?],
                        volume_mounts=[?],
                        dag=dag)
  </code></pre>