From 9bc1a4814e8d174544476a267730b49f6346eb50 Mon Sep 17 00:00:00 2001 From: John Belamaric Date: Mon, 5 Mar 2018 14:29:51 -0500 Subject: [PATCH] Update CoreDNS docs for beta (#7638) * Update CoreDNS docs for beta * Review comments --- docs/tasks/administer-cluster/coredns.md | 22 +++++++++++++++++++--- 1 file changed, 19 insertions(+), 3 deletions(-) diff --git a/docs/tasks/administer-cluster/coredns.md b/docs/tasks/administer-cluster/coredns.md index ca456104aa..c3415c1671 100644 --- a/docs/tasks/administer-cluster/coredns.md +++ b/docs/tasks/administer-cluster/coredns.md @@ -5,7 +5,7 @@ title: Using CoreDNS for Service Discovery min-kubernetes-server-version: v1.9 --- -{% include feature-state-alpha.md %} +{% include feature-state-beta.md %} {% capture overview %} This page describes how to enable CoreDNS instead of kube-dns for service @@ -20,8 +20,9 @@ discovery. ## Installing CoreDNS with kubeadm -In Kubernetes 1.9, [CoreDNS](https://coredns.io) is available as an alpha feature and -may be installed by setting the `CoreDNS` feature gate to `true` during `kubeadm init`: +In Kubernetes 1.9, [CoreDNS](https://coredns.io) is available as an alpha feature, and +in Kubernetes 1.10 it is available as a beta feature. In either case, you may install +it during cluster creation by setting the `CoreDNS` feature gate to `true` during `kubeadm init`: ``` kubeadm init --feature-gates=CoreDNS=true @@ -29,6 +30,21 @@ kubeadm init --feature-gates=CoreDNS=true This installs CoreDNS instead of kube-dns. +## Upgrading an Existing Cluster with kubeadm + +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 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. + +This process will be modified for the GA release of this feature, such that an existing +Corefile will not be overwritten. + {% endcapture %} {% capture whatsnext %}