title: Elastic Beanstalk docker error
body: <p>I'm getting a cryptic error when trying to update the configuration of a single-container Docker application.  Anybody have an idea of what might cause this, or how to go about debugging it?</p>
  
  <pre><code>ERROR [3009]  : Command execution failed:
     [CMD-ConfigDeploy/ConfigDeployStage0/ConfigDeployPreHook/00run.sh] 
     command failed with error code 1:
     /opt/elasticbeanstalk/hooks/configdeploy/pre/00run.sh
     docker: "tag" requires 2 arguments. See 'docker tag --help'.
     (ElasticBeanstalk::ActivityFatalError)
  </code></pre>