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| reviewers | title | min-kubernetes-server-version | content_template | |
|---|---|---|---|---|
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Using CoreDNS for Service Discovery | v1.9 | templates/task |
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{{% capture overview %}} This page describes how to enable CoreDNS instead of kube-dns for service discovery. {{% /capture %}}
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Installing CoreDNS with kubeadm
In Kubernetes 1.9, CoreDNS 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
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.
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You can configure CoreDNS to support many more use cases than
kube-dns by modifying the Corefile. For more information, see the
CoreDNS site.
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