602 lines
19 KiB
Markdown
602 lines
19 KiB
Markdown
---
|
||
translator:
|
||
- nicksu
|
||
reviewers:
|
||
- bowei
|
||
- zihongz
|
||
title: Debug DNS 方案
|
||
content_template: templates/task
|
||
---
|
||
|
||
<!--
|
||
|
||
{{% capture overview %}}
|
||
This page provides hints on diagnosing DNS problems.
|
||
{{% /capture %}}
|
||
|
||
-->
|
||
|
||
{{% capture overview %}}
|
||
这篇文章提供了一些关于 DNS 问题诊断的方法。
|
||
{{% /capture %}}
|
||
|
||
<!--
|
||
|
||
{{% capture prerequisites %}}
|
||
|
||
* {{< include "task-tutorial-prereqs.md" >}} {{< version-check >}}
|
||
* Kubernetes version 1.6 and above.
|
||
* The cluster must be configured to use the `coredns` (or `kube-dns`) addons.
|
||
{{% /capture %}}
|
||
|
||
{{% capture steps %}}
|
||
|
||
-->
|
||
|
||
{{% capture prerequisites %}}
|
||
|
||
- {{< include "task-tutorial-prereqs.md" >}} {{< version-check >}}
|
||
- Kubernetes 1.6 或者以上版本。
|
||
- 集群必须使用了 `coredns` (或者 `kube-dns`)插件。
|
||
{{% /capture %}}
|
||
|
||
{{% capture steps %}}
|
||
|
||
<!--
|
||
|
||
### Create a simple Pod to use as a test environment
|
||
|
||
Create a file named busybox.yaml with the following contents:
|
||
|
||
{{< codenew file="admin/dns/busybox.yaml" >}}
|
||
|
||
Then create a pod using this file and verify its status:
|
||
|
||
```shell
|
||
kubectl create -f https://k8s.io/examples/admin/dns/busybox.yaml
|
||
pod/busybox created
|
||
|
||
kubectl get pods busybox
|
||
NAME READY STATUS RESTARTS AGE
|
||
busybox 1/1 Running 0 <some-time>
|
||
```
|
||
|
||
-->
|
||
|
||
### 创建一个简单的 Pod 作为测试环境
|
||
|
||
新建一个名为 busybox.yaml 的文件并填入下列内容：
|
||
|
||
{{< codenew file="admin/dns/busybox.yaml" >}}
|
||
|
||
然后使用这个文件创建一个 Pod 并验证其状态：
|
||
|
||
```shell
|
||
kubectl create -f https://k8s.io/examples/admin/dns/busybox.yaml
|
||
pod/busybox created
|
||
|
||
kubectl get pods busybox
|
||
NAME READY STATUS RESTARTS AGE
|
||
busybox 1/1 Running 0 <some-time>
|
||
```
|
||
|
||
<!--
|
||
|
||
Once that pod is running, you can exec `nslookup` in that environment.
|
||
If you see something like the following, DNS is working correctly.
|
||
|
||
```shell
|
||
kubectl exec -ti busybox -- nslookup kubernetes.default
|
||
Server: 10.0.0.10
|
||
Address 1: 10.0.0.10
|
||
|
||
Name: kubernetes.default
|
||
Address 1: 10.0.0.1
|
||
```
|
||
|
||
If the `nslookup` command fails, check the following:
|
||
|
||
-->
|
||
|
||
只要 Pod 处于 running 状态，您就可以在环境里执行 `nslookup` 。
|
||
如果您看到类似下列的内容，则表示 DNS 是正常运行的。
|
||
|
||
```shell
|
||
kubectl exec -ti busybox -- nslookup kubernetes.default
|
||
Server: 10.0.0.10
|
||
Address 1: 10.0.0.10
|
||
|
||
Name: kubernetes.default
|
||
Address 1: 10.0.0.1
|
||
```
|
||
|
||
如果 `nslookup` 命令执行失败，请检查下列内容：
|
||
|
||
<!--
|
||
|
||
### Check the local DNS configuration first
|
||
|
||
Take a look inside the resolv.conf file.
|
||
(See [Inheriting DNS from the node](/docs/tasks/administer-cluster/dns-custom-nameservers/#inheriting-dns-from-the-node) and
|
||
[Known issues](#known-issues) below for more information)
|
||
|
||
```shell
|
||
kubectl exec busybox cat /etc/resolv.conf
|
||
```
|
||
|
||
Verify that the search path and name server are set up like the following
|
||
(note that search path may vary for different cloud providers):
|
||
|
||
```
|
||
search default.svc.cluster.local svc.cluster.local cluster.local google.internal c.gce_project_id.internal
|
||
nameserver 10.0.0.10
|
||
options ndots:5
|
||
```
|
||
|
||
-->
|
||
|
||
### 先检查本地的 DNS 配置
|
||
|
||
查看 resolv.conf 文件的内容
|
||
(阅读下面的 [从节点继承 DNS 配置](/docs/tasks/administer-cluster/dns-custom-nameservers/#inheriting-dns-from-the-node) 和
|
||
[已知问题](#known-issues) ，获取更多信息)
|
||
|
||
```shell
|
||
kubectl exec busybox cat /etc/resolv.conf
|
||
```
|
||
|
||
验证 search 和 name server 的配置是否类似下面的配置
|
||
(注意 search 根据不同的云提供商可能会有所不同):
|
||
|
||
```
|
||
search default.svc.cluster.local svc.cluster.local cluster.local google.internal c.gce_project_id.internal
|
||
nameserver 10.0.0.10
|
||
options ndots:5
|
||
```
|
||
|
||
<!--
|
||
|
||
Errors such as the following indicate a problem with the coredns/kube-dns add-on or
|
||
associated Services:
|
||
|
||
```
|
||
kubectl exec -ti busybox -- nslookup kubernetes.default
|
||
Server: 10.0.0.10
|
||
Address 1: 10.0.0.10
|
||
|
||
nslookup: can't resolve 'kubernetes.default'
|
||
```
|
||
|
||
or
|
||
|
||
```
|
||
kubectl exec -ti busybox -- nslookup kubernetes.default
|
||
Server: 10.0.0.10
|
||
Address 1: 10.0.0.10 kube-dns.kube-system.svc.cluster.local
|
||
|
||
nslookup: can't resolve 'kubernetes.default'
|
||
```
|
||
|
||
-->
|
||
|
||
下列错误表示 coredns/kube-dns 或者相关服务出现了问题：
|
||
|
||
```
|
||
kubectl exec -ti busybox -- nslookup kubernetes.default
|
||
Server: 10.0.0.10
|
||
Address 1: 10.0.0.10
|
||
|
||
nslookup: can't resolve 'kubernetes.default'
|
||
```
|
||
|
||
或者
|
||
|
||
```
|
||
kubectl exec -ti busybox -- nslookup kubernetes.default
|
||
Server: 10.0.0.10
|
||
Address 1: 10.0.0.10 kube-dns.kube-system.svc.cluster.local
|
||
|
||
nslookup: can't resolve 'kubernetes.default'
|
||
```
|
||
|
||
<!--
|
||
|
||
### Check if the DNS pod is running
|
||
|
||
Use the `kubectl get pods` command to verify that the DNS pod is running.
|
||
|
||
For CoreDNS:
|
||
```shell
|
||
kubectl get pods --namespace=kube-system -l k8s-app=kube-dns
|
||
NAME READY STATUS RESTARTS AGE
|
||
...
|
||
coredns-7b96bf9f76-5hsxb 1/1 Running 0 1h
|
||
coredns-7b96bf9f76-mvmmt 1/1 Running 0 1h
|
||
...
|
||
```
|
||
|
||
Or for kube-dns:
|
||
```shell
|
||
kubectl get pods --namespace=kube-system -l k8s-app=kube-dns
|
||
NAME READY STATUS RESTARTS AGE
|
||
...
|
||
kube-dns-v19-ezo1y 3/3 Running 0 1h
|
||
...
|
||
```
|
||
|
||
If you see that no pod is running or that the pod has failed/completed, the DNS
|
||
add-on may not be deployed by default in your current environment and you will
|
||
have to deploy it manually.
|
||
|
||
-->
|
||
|
||
### 检查 DNS Pod 是否运行
|
||
|
||
使用 `kubectl get pods` 命令来验证 DNS Pod 是否运行。
|
||
|
||
对于 CoreDNS 的情况:
|
||
|
||
```shell
|
||
kubectl get pods --namespace=kube-system -l k8s-app=kube-dns
|
||
NAME READY STATUS RESTARTS AGE
|
||
...
|
||
coredns-7b96bf9f76-5hsxb 1/1 Running 0 1h
|
||
coredns-7b96bf9f76-mvmmt 1/1 Running 0 1h
|
||
...
|
||
```
|
||
|
||
或者是 kube-dns:
|
||
|
||
```shell
|
||
kubectl get pods --namespace=kube-system -l k8s-app=kube-dns
|
||
NAME READY STATUS RESTARTS AGE
|
||
...
|
||
kube-dns-v19-ezo1y 3/3 Running 0 1h
|
||
...
|
||
```
|
||
|
||
如果您发现没有 pod 在运行，或者这些 Pod 的状态是 failed 或者 completed， 那可能这个 DNS 插件在您当前的环境里并没有成功部署，您将需要手动去部署它。
|
||
|
||
<!--
|
||
|
||
### Check for Errors in the DNS pod
|
||
|
||
Use `kubectl logs` command to see logs for the DNS containers.
|
||
|
||
For CoreDNS:
|
||
```shell
|
||
for p in $(kubectl get pods --namespace=kube-system -l k8s-app=kube-dns -o name); do kubectl logs --namespace=kube-system $p; done
|
||
```
|
||
|
||
Here is an example of a healthy CoreDNS log:
|
||
|
||
```
|
||
.:53
|
||
2018/08/15 14:37:17 [INFO] CoreDNS-1.2.2
|
||
2018/08/15 14:37:17 [INFO] linux/amd64, go1.10.3, 2e322f6
|
||
CoreDNS-1.2.2
|
||
linux/amd64, go1.10.3, 2e322f6
|
||
2018/08/15 14:37:17 [INFO] plugin/reload: Running configuration MD5 = 24e6c59e83ce706f07bcc82c31b1ea1c
|
||
```
|
||
|
||
-->
|
||
|
||
### 检查 DNS pod 里的错误
|
||
|
||
使用 `kubectl logs` 命令来查看 DNS 容器的日志信息。
|
||
|
||
对于 CoreDNS:
|
||
|
||
```shell
|
||
for p in $(kubectl get pods --namespace=kube-system -l k8s-app=kube-dns -o name); do kubectl logs --namespace=kube-system $p; done
|
||
```
|
||
|
||
下列是一个正常运行的 CoreDNS 日志信息：
|
||
|
||
```
|
||
.:53
|
||
2018/08/15 14:37:17 [INFO] CoreDNS-1.2.2
|
||
2018/08/15 14:37:17 [INFO] linux/amd64, go1.10.3, 2e322f6
|
||
CoreDNS-1.2.2
|
||
linux/amd64, go1.10.3, 2e322f6
|
||
2018/08/15 14:37:17 [INFO] plugin/reload: Running configuration MD5 = 24e6c59e83ce706f07bcc82c31b1ea1c
|
||
```
|
||
|
||
<!--
|
||
|
||
For kube-dns, there are 3 sets of logs:
|
||
|
||
```shell
|
||
kubectl logs --namespace=kube-system $(kubectl get pods --namespace=kube-system -l k8s-app=kube-dns -o name | head -1) -c kubedns
|
||
|
||
kubectl logs --namespace=kube-system $(kubectl get pods --namespace=kube-system -l k8s-app=kube-dns -o name | head -1) -c dnsmasq
|
||
|
||
kubectl logs --namespace=kube-system $(kubectl get pods --namespace=kube-system -l k8s-app=kube-dns -o name | head -1) -c sidecar
|
||
```
|
||
|
||
See if there are any suspicious error messages in the logs. In kube-dns, a '`W`', '`E`' or '`F`' at the beginning
|
||
of a line represents a Warning, Error or Failure. Please search for entries that have these
|
||
as the logging level and use
|
||
[kubernetes issues](https://github.com/kubernetes/kubernetes/issues)
|
||
to report unexpected errors.
|
||
|
||
-->
|
||
|
||
对于 kube-dns, 总共有三种类型的日志需要查看：
|
||
|
||
```shell
|
||
kubectl logs --namespace=kube-system $(kubectl get pods --namespace=kube-system -l k8s-app=kube-dns -o name | head -1) -c kubedns
|
||
|
||
kubectl logs --namespace=kube-system $(kubectl get pods --namespace=kube-system -l k8s-app=kube-dns -o name | head -1) -c dnsmasq
|
||
|
||
kubectl logs --namespace=kube-system $(kubectl get pods --namespace=kube-system -l k8s-app=kube-dns -o name | head -1) -c sidecar
|
||
```
|
||
|
||
看日志信息里是否有可疑的错误，对于 kube-dns, 一个 '`W`', '`E`' 或者 '`F`' 开头的行表示对应的 Warning（警告）， Error（错误）或者 Failure（失败）。请搜索日志等级是否有这样的关键字的日志信息并使用 [kubernetes issues](https://github.com/kubernetes/kubernetes/issues) 来提交错误报告。
|
||
|
||
### 检查是否启用了 DNS 服务
|
||
|
||
使用`kubectl get service` 命令来检查 DNS 服务是否已经启用。
|
||
|
||
```shell
|
||
kubectl get svc --namespace=kube-system
|
||
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
|
||
...
|
||
kube-dns ClusterIP 10.0.0.10 <none> 53/UDP,53/TCP 1h
|
||
...
|
||
```
|
||
|
||
注意不管是 CoreDNS 还是 kube-dns ， 这个 service 的名字都会是“kube-dns” 。
|
||
如果您已经创建了这个 service 或者说在这个例子里它应该是默认自动创建的，但是它并没有出现，请阅读 [services 纠错](/docs/tasks/debug-application-cluster/debug-service/)来获取更多信息。
|
||
|
||
<!--
|
||
|
||
### Are DNS endpoints exposed?
|
||
|
||
You can verify that DNS endpoints are exposed by using the `kubectl get endpoints`
|
||
command.
|
||
|
||
```shell
|
||
kubectl get ep kube-dns --namespace=kube-system
|
||
NAME ENDPOINTS AGE
|
||
kube-dns 10.180.3.17:53,10.180.3.17:53 1h
|
||
```
|
||
|
||
If you do not see the endpoints, see endpoints section in the
|
||
[debugging services](/docs/tasks/debug-application-cluster/debug-service/) documentation.
|
||
|
||
For additional Kubernetes DNS examples, see the
|
||
[cluster-dns examples](https://github.com/kubernetes/examples/tree/master/staging/cluster-dns)
|
||
in the Kubernetes GitHub repository.
|
||
|
||
-->
|
||
|
||
### DNS 的 endpoints 公开了吗？
|
||
|
||
您可以使用 `kubectl get endpoints`命令来验证 DNS 的 endpoint 是否公开了。
|
||
|
||
```shell
|
||
kubectl get ep kube-dns --namespace=kube-system
|
||
NAME ENDPOINTS AGE
|
||
kube-dns 10.180.3.17:53,10.180.3.17:53 1h
|
||
```
|
||
|
||
如果您没看到对应的 endpoints， 请阅读[services 纠错](/docs/tasks/debug-application-cluster/debug-service/)的 endpoints 小节。
|
||
|
||
若需要更多的 Kubernetes DNS 例子，请在 Kubernetes GitHub 仓库里查看[cluster-dns 例子](https://github.com/kubernetes/examples/tree/master/staging/cluster-dns) 。
|
||
|
||
<!--
|
||
|
||
### Are DNS queries being received/processed?
|
||
|
||
You can verify if queries are being received by CoreDNS by adding the `log` plugin to the CoreDNS configuration (aka Corefile).
|
||
The CoreDNS Corefile is held in a ConfigMap named `coredns`. To edit it, use the command ...
|
||
|
||
```
|
||
kubectl -n kube-system edit configmap coredns
|
||
```
|
||
|
||
-->
|
||
|
||
### DNS 查询有被接收或者执行吗？
|
||
|
||
您可以通过给 CoreDNS 的配置文件 (也叫 Corefile)添加`log`插件来判断查询是否被正确接收。
|
||
CoreDNS 的 Corefile 被保存在一个叫 `coredns` 的 ConfigMap 里，使用下列命令来编辑它：
|
||
|
||
```
|
||
kubectl -n kube-system edit configmap coredns
|
||
```
|
||
|
||
<!--
|
||
|
||
Then add `log` in the Corefile section per the example below.
|
||
|
||
```
|
||
apiVersion: v1
|
||
kind: ConfigMap
|
||
metadata:
|
||
name: coredns
|
||
namespace: kube-system
|
||
data:
|
||
Corefile: |
|
||
.:53 {
|
||
log
|
||
errors
|
||
health
|
||
kubernetes cluster.local in-addr.arpa ip6.arpa {
|
||
pods insecure
|
||
upstream
|
||
fallthrough in-addr.arpa ip6.arpa
|
||
}
|
||
prometheus :9153
|
||
proxy . /etc/resolv.conf
|
||
cache 30
|
||
loop
|
||
reload
|
||
loadbalance
|
||
}
|
||
|
||
```
|
||
|
||
After saving the changes, it may take up to minute or two for Kubernetes to propagate these changes to the CoreDNS pods.
|
||
|
||
-->
|
||
|
||
然后类似下面的例子给 Corefile 添加 `log`。
|
||
|
||
```
|
||
apiVersion: v1
|
||
kind: ConfigMap
|
||
metadata:
|
||
name: coredns
|
||
namespace: kube-system
|
||
data:
|
||
Corefile: |
|
||
.:53 {
|
||
log
|
||
errors
|
||
health
|
||
kubernetes cluster.local in-addr.arpa ip6.arpa {
|
||
pods insecure
|
||
upstream
|
||
fallthrough in-addr.arpa ip6.arpa
|
||
}
|
||
prometheus :9153
|
||
proxy . /etc/resolv.conf
|
||
cache 30
|
||
loop
|
||
reload
|
||
loadbalance
|
||
}
|
||
|
||
```
|
||
|
||
保存这些更改后，您可能会需要等待一到两分钟让 Kubernetes 把这些更改应用到 CoreDNS 的 pods 里。
|
||
|
||
<!--
|
||
|
||
Next, make some queries and view the logs per the sections above in this document. If CoreDNS pods are receiving the queries, you should see them in the logs.
|
||
|
||
Here is an example of a query in the log.
|
||
|
||
```
|
||
.:53
|
||
2018/08/15 14:37:15 [INFO] CoreDNS-1.2.0
|
||
2018/08/15 14:37:15 [INFO] linux/amd64, go1.10.3, 2e322f6
|
||
CoreDNS-1.2.0
|
||
linux/amd64, go1.10.3, 2e322f6
|
||
2018/09/07 15:29:04 [INFO] plugin/reload: Running configuration MD5 = 162475cdf272d8aa601e6fe67a6ad42f
|
||
2018/09/07 15:29:04 [INFO] Reloading complete
|
||
172.17.0.18:41675 - [07/Sep/2018:15:29:11 +0000] 59925 "A IN kubernetes.default.svc.cluster.local. udp 54 false 512" NOERROR qr,aa,rd,ra 106 0.000066649s
|
||
|
||
```
|
||
|
||
-->
|
||
|
||
接下来，发起一些查询并依照本文上面章节的内容查看日志信息，如果 CoreDNS 的 pods 接收到这些查询，您将可以在日志信息里看到他们。
|
||
|
||
下面是日志信息里的查询例子：
|
||
|
||
```
|
||
.:53
|
||
2018/08/15 14:37:15 [INFO] CoreDNS-1.2.0
|
||
2018/08/15 14:37:15 [INFO] linux/amd64, go1.10.3, 2e322f6
|
||
CoreDNS-1.2.0
|
||
linux/amd64, go1.10.3, 2e322f6
|
||
2018/09/07 15:29:04 [INFO] plugin/reload: Running configuration MD5 = 162475cdf272d8aa601e6fe67a6ad42f
|
||
2018/09/07 15:29:04 [INFO] Reloading complete
|
||
172.17.0.18:41675 - [07/Sep/2018:15:29:11 +0000] 59925 "A IN kubernetes.default.svc.cluster.local. udp 54 false 512" NOERROR qr,aa,rd,ra 106 0.000066649s
|
||
|
||
```
|
||
|
||
<!--
|
||
|
||
## Known issues
|
||
|
||
Some Linux distributions (e.g. Ubuntu), use a local DNS resolver by default (systemd-resolved).
|
||
Systemd-resolved moves and replaces `/etc/resolv.conf` with a stub file that can cause a fatal forwarding
|
||
loop when resolving names in upstream servers. This can be fixed manually by using kubelet's `--resolv-conf` flag
|
||
to point to the correct `resolv.conf` (With `systemd-resolved`, this is `/run/systemd/resolve/resolv.conf`).
|
||
kubeadm (>= 1.11) automatically detects `systemd-resolved`, and adjusts the kubelet flags accordingly.
|
||
|
||
-->
|
||
|
||
## 已知问题
|
||
|
||
有些 Linux 发行版本 (比如 Ubuntu)， 默认使用一个本地的 DNS 解析器 (systemd-resolved)。
|
||
Systemd-resolved 会用一个 stub 文件来覆盖 `/etc/resolv.conf`从而在解析域名的时候导致了重复向 DNS 上游服务器推送请求。 这个问题可以通过手动指定 kubelet 的 `--resolv-conf` 标签为正确的 `resolv.conf` (如果是 `systemd-resolved`，则这个文件路径为 `/run/systemd/resolve/resolv.conf`) 来解决。
|
||
kubeadm (>= 1.11) 会自动检测`systemd-resolved`并对应的更改 kubelet 的标签。
|
||
|
||
<!--
|
||
|
||
Kubernetes installs do not configure the nodes' `resolv.conf` files to use the
|
||
cluster DNS by default, because that process is inherently distribution-specific.
|
||
This should probably be implemented eventually.
|
||
|
||
Linux's libc is impossibly stuck ([see this bug from
|
||
2005](https://bugzilla.redhat.com/show_bug.cgi?id=168253)) with limits of just
|
||
3 DNS `nameserver` records and 6 DNS `search` records. Kubernetes needs to
|
||
consume 1 `nameserver` record and 3 `search` records. This means that if a
|
||
local installation already uses 3 `nameserver`s or uses more than 3 `search`es,
|
||
some of those settings will be lost. As a partial workaround, the node can run
|
||
`dnsmasq` which will provide more `nameserver` entries, but not more `search`
|
||
entries. You can also use kubelet's `--resolv-conf` flag.
|
||
|
||
If you are using Alpine version 3.3 or earlier as your base image, DNS may not
|
||
work properly owing to a known issue with Alpine.
|
||
Check [here](https://github.com/kubernetes/kubernetes/issues/30215)
|
||
for more information.
|
||
|
||
-->
|
||
|
||
Kubernetes 的安装并不会默认配置节点的 `resolv.conf` 文件来使用集群的 DNS 服务，因为这个配置对于不同的发行版本是不一样的。这个问题应该迟早会被解决的。
|
||
|
||
Linux 的 libc 会在仅有三个 DNS 的 `nameserver` 和六个 DNS 的`search` 记录时会不可思议的卡死 ([详情请查阅这个2005年的bug](https://bugzilla.redhat.com/show_bug.cgi?id=168253))。Kubernetes 需要占用一个 `nameserver` 记录和三个`search`记录。这意味着如果一个本地的安装已经使用了三个`nameserver`或者使用了超过三个的 `search`记录，那有些配置很可能会丢失。有一个不完整的解决方案就是在节点上使用`dnsmasq`来提供更多的`nameserver`配置，但是无法提供更多的`search`记录。您也可以使用kubelet 的 `--resolv-conf` 标签来解决这个问题。
|
||
|
||
如果您是使用 Alpine 3.3 或者更早版本作为您的基础镜像，DNS 可能会由于Alpine 一个已知的问题导致无法正常工作，请查看[这里](https://github.com/kubernetes/kubernetes/issues/30215)获取更多资料。
|
||
|
||
<!--
|
||
|
||
## Kubernetes Federation (Multiple Zone support)
|
||
|
||
Release 1.3 introduced Cluster Federation support for multi-site Kubernetes
|
||
installations. This required some minor (backward-compatible) changes to the
|
||
way the Kubernetes cluster DNS server processes DNS queries, to facilitate
|
||
the lookup of federated services (which span multiple Kubernetes clusters).
|
||
See the [Cluster Federation Administrators' Guide](/docs/concepts/cluster-administration/federation/)
|
||
for more details on Cluster Federation and multi-site support.
|
||
|
||
## -->
|
||
|
||
## Kubernetes Federation (支持多区域部署)
|
||
|
||
自从 1.3 版本支持了多个 Kubernetes 的联邦集群后，集群 DNS 服务在处理 DNS 请求时需要有一些微弱的调整 (这是向下兼容的)，从而可以使用跨越多个 Kubernetes 集群的联邦服务。请看 [联邦集群管理向导](/docs/concepts/cluster-administration/federation/) 获取更多关于联邦集群和多点支持的信息。
|
||
|
||
<!--
|
||
|
||
## References
|
||
|
||
- [DNS for Services and Pods](/docs/concepts/services-networking/dns-pod-service/)
|
||
- [Docs for the kube-dns DNS cluster addon](http://releases.k8s.io/{{< param "githubbranch" >}}/cluster/addons/dns/kube-dns/README.md)
|
||
|
||
## What's next
|
||
- [Autoscaling the DNS Service in a Cluster](/docs/tasks/administer-cluster/dns-horizontal-autoscaling/).
|
||
|
||
{{% /capture %}}
|
||
|
||
## -->
|
||
|
||
## 参考
|
||
|
||
- [Services 和 Pods 的 DNS 指南](/docs/concepts/services-networking/dns-pod-service/)
|
||
- [kube-dns DNS 插件文档](http://releases.k8s.io/{{< param "githubbranch" >}}/cluster/addons/dns/kube-dns/README.md)
|
||
|
||
## 接下来
|
||
|
||
- [集群里自动伸缩 DNS Service](/docs/tasks/administer-cluster/dns-horizontal-autoscaling/).
|
||
|
||
{{% /capture %}}
|
||
|
||
|
||
|