Updated dns-pod-service.md (#9552)

* Updated dns-pod-service.md

Added a note on A records creation

* Updated dns-pod-service.md

Added Hugo  {{ note }} shortcode

* Update dns-pod-service.md

Changed wording

* tighten up the wording

Author: dsalamancaMS

content/en/docs/concepts/services-networking/dns-pod-service.md

@@ -148,6 +148,10 @@ A record at that name, pointing to the Pod's IP. Both pods "`busybox1`" and
 The Endpoints object can specify the `hostname` for any endpoint addresses,
 along with its IP.
 
+{{< note >}}
+**Note:** Because A records are not created for Pod names, `hostname` is required for the Pod's A record to be created. A Pod with no `hostname` but with `subdomain` only will only create the A record for the headless service (`default-subdomain.my-namespace.svc.cluster.local`), pointing to the Pod's IP address.
+{{< /note >}}
+
 ### Pod's DNS Policy
 
 DNS policies can be set on a per-pod basis. Currently Kubernetes supports the