title: ExternalName pointing to service in other namespace doesn't resolve unless given full FQDN
body: <p>I've a Service <code>my-service</code> of type ClusterIP in namespace <code>A</code> which can load balance to a few pods. I want to create another Service of type ExternalName in namespace <code>B</code> that points to <code>my-service</code> in namespace <code>A</code>.</p>
  
  <p>I create the following YAML:</p>
  
  <pre class="lang-yaml prettyprint-override"><code>apiVersion: v1
  kind: Service
  metadata:
    name: my-service
    namespace: B
  spec:
    type: ExternalName
    externalName: my-service.A
  </code></pre>
  
  <p>and if I exec into a pod running in namespace <code>B</code> and do:</p>
  
  <pre><code># ping my-service
  ping: my-service: Name or service not known
  </code></pre>
  
  <p>But if I change the <code>externalName</code> in the above YAML to below:</p>
  
  <pre class="lang-yaml prettyprint-override"><code>apiVersion: v1
  kind: Service
  metadata:
    name: my-service
    namespace: B
  spec:
    type: ExternalName
    externalName: my-service.A.svc.cluster.local   &lt;--- full FQDN here
  </code></pre>
  
  <p>things work as expected. Also, if I ping <code>my-service</code> directly from a pod in namespace <code>B</code> it is being resolved:</p>
  
  <pre><code># ping my-service.A
  PING my-service.A.svc.cluster.local (10.0.80.133) 56(84) bytes of data.
  </code></pre>
  
  <p>Why <code>my-service.A</code> is not resolved to <code>my-service.A.svc.cluster.local</code>  in ExternalName Service?</p>
  
  <p>My K8s version is <code>1.14.8</code> and uses CoreDNS.</p>