title: How to search for an docker image in multiple private registries
body: <p>When we are searching for an image in our private registry we need to specify the host "docker search 10.10.10.10:5000/apache"
  If we execute "docker search apache" docker is looking for an image only in the official docher hub registry.
  Our use case:</p>
  
  <pre><code>FROM organization/apache
  # .....
  # custom instructions
  </code></pre>
  
  <p>We want to search this image in our registry(without providing registry host), and if it is not found use public docker hub registry.
  Is it possible to configure docker client to do this?</p>