---
title: 使用 CoreDNS 进行服务发现
min-kubernetes-server-version: v1.9
content_type: task
---

<!--
reviewers:
- johnbelamaric
title: Using CoreDNS for Service Discovery
min-kubernetes-server-version: v1.9
content_type: task
-->

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<!--
This page describes the CoreDNS upgrade process and how to install CoreDNS instead of kube-dns.
-->
此页面介绍了 CoreDNS 升级过程以及如何安装 CoreDNS 而不是 kube-dns。

## {{% heading "prerequisites" %}}

{{< include "task-tutorial-prereqs.md" >}} {{< version-check >}}

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<!--
## About CoreDNS

[CoreDNS](https://coredns.io) is a flexible, extensible DNS server that can serve as the Kubernetes cluster DNS.
Like Kubernetes, the CoreDNS project is hosted by the {{< glossary_tooltip text="CNCF" term_id="cncf" >}}.
-->
## 关于 CoreDNS

[CoreDNS](https://coredns.io) 是一个灵活可扩展的 DNS 服务器，可以作为 Kubernetes 集群 DNS。
与 Kubernetes 一样，CoreDNS 项目由 {{< glossary_tooltip text="CNCF" term_id="cncf" >}} 托管。

<!--
You can use CoreDNS instead of kube-dns in your cluster by replacing kube-dns in an existing
deployment, or by using tools like kubeadm that will deploy and upgrade the cluster for you.
-->
通过在现有的集群中替换 kube-dns，可以在集群中使用 CoreDNS 代替 kube-dns 部署，
或者使用 kubeadm 等工具来为你部署和升级集群。

<!--
## Installing CoreDNS

For manual deployment or replacement of kube-dns, see the documentation at the
[CoreDNS GitHub project.](https://github.com/coredns/deployment/tree/master/kubernetes)
-->
## 安装 CoreDNS

有关手动部署或替换 kube-dns，请参阅
[CoreDNS GitHub 工程](https://github.com/coredns/deployment/tree/master/kubernetes)。

<!--
## Migrating to CoreDNS

### Upgrading an existing cluster with kubeadm
-->

## 迁移到 CoreDNS

### 使用 kubeadm 升级现有集群

<!--
In Kubernetes version 1.10 and later, 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 
stub domains, and upstream name server.
-->
在 Kubernetes 1.10 及更高版本中，当你使用 `kubeadm` 升级使用 `kube-dns` 的集群时，你还可以迁移到 CoreDNS。
在本例中 `kubeadm` 将生成 CoreDNS 配置（"Corefile"）基于 `kube-dns` ConfigMap，
保存存根域和上游名称服务器的配置。

<!--
If you are moving from kube-dns to CoreDNS, make sure to set the `CoreDNS` feature gate to `true`
during an upgrade. For example, here is what a `v1.11.0` upgrade would look like:
-->
如果你正在从 kube-dns 迁移到 CoreDNS，请确保在升级期间将 `CoreDNS` 特性门设置为 `true`。
例如，`v1.11.0` 升级应该是这样的:

```
kubeadm upgrade apply v1.11.0 --feature-gates=CoreDNS=true
```

<!--
In Kubernetes version 1.13 and later the `CoreDNS` feature gate is removed and CoreDNS
is used by default. 
-->
在 Kubernetes 版本 1.13 和更高版本中，`CoreDNS`特性门已经删除，CoreDNS 在默认情况下使用。

<!--
In versions prior to 1.11 the 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.
-->
在 1.11 之前的版本中，核心文件将被升级过程中创建的文件覆盖。
**如果已对其进行自定义，则应保存现有的 ConfigMap。** 
在新的 ConfigMap 启动并运行后，你可以重新应用自定义。

<!--
If you are running CoreDNS in Kubernetes version 1.11 and later, during upgrade,
your existing Corefile will be retained.
-->
如果你在 Kubernetes 1.11 及更高版本中运行 CoreDNS，则在升级期间，将保留现有的 Corefile。

<!--
In Kubernetes version 1.21, support for `kube-dns` is removed from kubeadm.
-->
在 kubernetes 1.21 中，kubeadm 移除了对 `kube-dns` 的支持。

<!--
## Upgrading CoreDNS 

CoreDNS is available in Kubernetes since v1.9. 
You can check the version of CoreDNS shipped with Kubernetes and the changes made to CoreDNS [here](https://github.com/coredns/deployment/blob/master/kubernetes/CoreDNS-k8s_version.md).
-->
## 升级 CoreDNS 

从 v1.9 起，Kubernetes 提供了 CoreDNS。
你可以在[此处](https://github.com/coredns/deployment/blob/master/kubernetes/CoreDNS-k8s_version.md)
查看 Kubernetes 随附的 CoreDNS 版本以及对 CoreDNS 所做的更改。

<!--
CoreDNS can be upgraded manually in case you want to only upgrade CoreDNS or use your own custom image.
There is a helpful [guideline and walkthrough](https://github.com/coredns/deployment/blob/master/kubernetes/Upgrading_CoreDNS.md) available to ensure a smooth upgrade.
-->
如果你只想升级 CoreDNS 或使用自己的自定义镜像，则可以手动升级 CoreDNS。
参看[指南和演练](https://github.com/coredns/deployment/blob/master/kubernetes/Upgrading_CoreDNS.md)
文档了解如何平滑升级。


<!--
## Tuning CoreDNS

When resource utilisation is a concern, it may be useful to tune the configuration of CoreDNS. For more details, check out the
[documentation on scaling CoreDNS]((https://github.com/coredns/deployment/blob/master/kubernetes/Scaling_CoreDNS.md)).
-->
## CoreDNS 调优

当资源利用方面有问题时，优化 CoreDNS 的配置可能是有用的。
有关详细信息，请参阅[有关扩缩 CoreDNS 的文档](https://github.com/coredns/deployment/blob/master/kubernetes/Scaling_CoreDNS.md)。

## {{% heading "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/).
-->
你可以通过修改 `Corefile` 来配置 [CoreDNS](https://coredns.io)，以支持比 kube-dns 更多的用例。
请参考 [CoreDNS 网站](https://coredns.io/2017/05/08/custom-dns-entries-for-kubernetes/)
以了解更多信息。