Review comments

docs/tasks/administer-cluster/coredns.md

@@ -1,5 +1,5 @@
 ---
-reviewers:
+approvers:
 - johnbelamaric
 title: Using CoreDNS for Service Discovery
 min-kubernetes-server-version: v1.9
@@ -32,21 +32,18 @@ This installs CoreDNS instead of kube-dns.
 
 ## Upgrading an Existing Cluster with kubeadm
 
-In Kuberentes 1.10, you can also move to CoreDNS when you use `kubeadm` to upgrade
+In Kubernetes 1.10, you can also move to CoreDNS when you use `kubeadm` to upgrade
 a cluster that is using `kube-dns`. In this case, `kubeadm` will generate the CoreDNS configuration
 ("Corefile") based upon the `kube-dns` ConfigMap, preserving configurations for federation,
 stub domains, and upstream name server.
 
-Note that if you are running CoreDNS already in your cluster, this conversion is not possible,
-as your Corefile may contain other customizations which should not be overwritten. In that
-case, it is recommended that you update your Corefile according to the changes you can find
-in the [recommended CoreDNS Kubernetes manifest](https://github.com/coredns/deployment/tree/master/kubernetes).
+Note that if you are running CoreDNS in your cluster already, prior to upgrade, your existing Corefile will be
+**overwritten** by the one created during upgrade. **You should save your existing ConfigMap
+if you have customized it.** You may re-apply your customizations after the new ConfigMap is
+up and running.
 
-In particular, changes that may be important are:
-
-* Updating the image to `coredns/coredns:1.0.6`
-* Changing `upstream /etc/resolv.conf` to just `upstream`, which changes external service CNAME lookups
-  to go through CoreDNS rather than directly through and external name server.
+This process will be modified for the GA release of this feature, such that an existing
+Corefile will not be overwritten.
 
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