60 lines
1.9 KiB
Markdown
60 lines
1.9 KiB
Markdown
---
|
|||
|
|
reviewers:
|
||
- johnbelamaric
|
|||
title: Using CoreDNS for Service Discovery
|
|||
min-kubernetes-server-version: v1.9
|
|||
|
content_template: templates/task
|
||
---
|
|||
|
|||
|
|
{{< feature-state state="beta" >}}
|
||
|
|||
|
|
{{% capture overview %}}
|
||
This page describes how to enable CoreDNS instead of kube-dns for service
|
|||
discovery.
|
|||
|
|
{{% /capture %}}
|
||
|
|||
|
|
{{% capture prerequisites %}}
|
||
{{< include "task-tutorial-prereqs.md" >}} {{< version-check >}}
|
|||
{{% /capture %}}
|
|||
|
|||
|
|
{{% capture steps %}}
|
||
|
|||
## Installing CoreDNS with kubeadm
|
|||
|
|||
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
|
|||
```
|
|||
|
|||
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.
|
|||
|
|||
|
|
{{% /capture %}}
|
||
|
|||
|
|
{{% capture whatsnext %}}
|
||
|
|||
You can configure [CoreDNS](https://coredns.io) to support many more use cases than
|
|||
kube-dns by modifying the `Corefile`. For more information, see the
|
|||
|
|
[CoreDNS site](https://coredns.io/2017/05/08/custom-dns-entries-for-kubernetes/).
|
||
|
|||
|
|
{{% /capture %}}
|
||
|
|||
|
