Merge pull request #23147 from tengqm/zh-resync-dns-scaling

[zh] Resync DNS autoscaling task
This commit is contained in:
Kubernetes Prow Robot 2020-08-17 18:01:31 -07:00 committed by GitHub
commit 7b130d09d4
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
1 changed files with 164 additions and 236 deletions

View File

@ -1,12 +1,10 @@
---
title: 集群 DNS 服务自动伸缩
title: 自动扩缩集群 DNS 服务
content_type: task
---
<!--
---
title: Autoscale the DNS Service in a Cluster
content_type: task
---
-->
<!-- overview -->
@ -14,12 +12,10 @@ content_type: task
This page shows how to enable and configure autoscaling of the DNS service in a
Kubernetes cluster.
-->
本页展示了如何在集群中启用和配置 DNS 服务的自动伸缩功能。
本页展示了如何在集群中启用和配置 DNS 服务的自动扩缩功能。
## {{% heading "prerequisites" %}}
* {{< include "task-tutorial-prereqs.md" >}} {{< version-check >}}
<!--
@ -29,14 +25,12 @@ Kubernetes cluster.
* Kubernetes version 1.4.0 or later is recommended.
-->
* 本指南假设的节点使用 AMD64 或 Intel 64 CPU 架构
* 本指南假设的节点使用 AMD64 或 Intel 64 CPU 架构
* 确保已启用 [DNS 功能](/docs/concepts/services-networking/dns-pod-service/)本身。
* 确保已启用 [DNS 功能](/zh/docs/concepts/services-networking/dns-pod-service/)本身。
* 建议使用 Kubernetes 1.4.0 或更高版本。
<!-- steps -->
<!--
@ -60,7 +54,7 @@ If you see "dns-autoscaler" in the output, DNS horizontal autoscaling is
already enabled, and you can skip to
[Tuning autoscaling parameters](#tuning-autoscaling-parameters).
-->
## 确定是否 DNS 水平 水平自动伸缩特性已经启用
## 确定是否 DNS 水平 水平自动扩缩特性已经启用 {#determining-whether-dns-horizontal-autoscaling-is-already-enabled}
在 kube-system 命名空间中列出集群中的 {{< glossary_tooltip text="Deployments" term_id="deployment" >}}
@ -70,15 +64,18 @@ kubectl get deployment --namespace=kube-system
输出类似如下这样:
NAME DESIRED CURRENT UP-TO-DATE AVAILABLE AGE
...
dns-autoscaler 1 1 1 1 ...
...
```
NAME DESIRED CURRENT UP-TO-DATE AVAILABLE AGE
...
dns-autoscaler 1 1 1 1 ...
...
```
如果在输出中看到 “dns-autoscaler”说明 DNS 水平自动伸缩已经启用,可以跳到 [调优自动伸缩参数](#tuning-autoscaling-parameters)。
如果在输出中看到 “dns-autoscaler”说明 DNS 水平自动扩缩已经启用,可以跳到
[调优自动扩缩参数](#tuning-autoscaling-parameters)。
<!--
## Getting the name of your DNS Deployment or ReplicationController
## Getting the name of your DNS Deployment {#find-scaling-target}
List the Deployments in your cluster in the kube-system namespace:
@ -87,127 +84,88 @@ kubectl get deployment --namespace=kube-system
```
The output is similar to this:
-->
## 获取 DNS Deployment 的名称 {#find-scaling-target}
NAME DESIRED CURRENT UP-TO-DATE AVAILABLE AGE
...
coredns 2 2 2 2 ...
...
In Kubernetes versions earlier than 1.12, the DNS Deployment was called "kube-dns".
In Kubernetes versions earlier than 1.5 DNS was implemented using a
ReplicationController instead of a Deployment. So if you don't see kube-dns,
or a similar name, in the preceding output, list the ReplicationControllers in
your cluster in the kube-system namespace:
列出集群内 kube-system 名字空间中的 DNS Deployment
```shell
kubectl get rc --namespace=kube-system
kubectl get deployment -l k8s-app=kube-dns --namespace=kube-system
```
The output is similar to this:
输出类似如下这样:
NAME DESIRED CURRENT READY AGE
...
kube-dns-v20 1 1 1 ...
...
```
NAME READY UP-TO-DATE AVAILABLE AGE
...
coredns 2/2 2 2 ...
...
```
<!--
If you don't see a Deployment for DNS services, you can also look for it by name:
-->
## 获取 DNS Deployment 或 ReplicationController 的名称
列出集群内 kube-system namespace 中的 Deployment
如果看不到 DNS 服务的 Deployment你也可以通过名字来查找
```shell
kubectl get deployment --namespace=kube-system
```
输出类似如下这样:
<!--
and look for a deployment named `coredns` or `kube-dns`.
-->
并在输出中寻找名称为 `coredns``kube-dns` 的 Deployment。
NAME DESIRED CURRENT UP-TO-DATE AVAILABLE AGE
...
coredns 2 2 2 2 ...
...
<!--
Your scale target is:
-->
你的扩缩目标为:
在早于 1.12 的 Kubernetes 版本中DNS 部署称为 “kube-dns”。
Kubernetes 1.5 或之前版本DNS 通过使用 ReplicationController 来实现,而不是 Deployment。 所以看不到 kube-dns 或者类似的名称,在之前的输出中,列出了集群内 kube-system namespace 中的 ReplicationController
```shell
kubectl get rc --namespace=kube-system
```
Deployment/<your-deployment-name>
```
输出类似如下这样:
NAME DESIRED CURRENT READY AGE
...
kube-dns-v20 1 1 1 ...
...
<!--
## Determining your scale target
If you have a DNS Deployment, your scale target is:
Deployment/<your-deployment-name>
where `<your-deployment-name>` is the name of your DNS Deployment. For example, if
your DNS Deployment name is coredns, your scale target is Deployment/coredns.
If you have a DNS ReplicationController, your scale target is:
ReplicationController/<your-rc-name>
where `<your-rc-name>` is the name of your DNS ReplicationController. For example,
if your DNS ReplicationController name is kube-dns-v20, your scale target is
ReplicationController/kube-dns-v20.
-->
## 确定伸缩目标
如果有一个 DNS Deployment伸缩目标是
Deployment/<your-deployment-name>
其中 `<your-deployment-name>` 是 DNS 部署的名称。例如,如果您的 DNS 部署名称是 coredns则您的扩展目标是 Deployment/coredns。
如果有一个 DNS ReplicationController那么伸缩目标为
ReplicationController/<your-rc-name>
这里 `<your-rc-name>` 是 DNS ReplicationController 的名称。 例如DNS ReplicationController 的名称是 kube-dns-v20则伸缩目标为 ReplicationController/kube-dns-v20。
其中 `<your-deployment-name>` 是 DNS Deployment 的名称。
例如,如果你的 DNS Deployment 名称是 `coredns`,则你的扩展目标是 Deployment/coredns。
<!--
## Enabling DNS horizontal autoscaling
CoreDNS is the default DNS service for Kubernetes. CoreDNS sets the label
`k8s-app=kube-dns` so that it can work in clusters that originally used
kube-dns.
-->
{{< note >}}
CoreDNS 是 Kubernetes 的默认 DNS 服务。CoreDNS 设置标签 `k8s-app=kube-dns`
以便能够在原来使用 `kube-dns` 的集群中工作。
{{< /note >}}
<!--
## Enabling DNS horizontal autoscaling {#enablng-dns-horizontal-autoscaling}
In this section, you create a Deployment. The Pods in the Deployment run a
container based on the `cluster-proportional-autoscaler-amd64` image.
Create a file named `dns-horizontal-autoscaler.yaml` with this content:
{{< codenew file="admin/dns/dns-horizontal-autoscaler.yaml" >}}
In the file, replace `<SCALE_TARGET>` with your scale target.
Go to the directory that contains your configuration file, and enter this
command to create the Deployment:
```shell
kubectl apply -f dns-horizontal-autoscaler.yaml
```
The output of a successful command is:
deployment.apps/dns-autoscaler created
DNS horizontal autoscaling is now enabled.
-->
## 启用 DNS 水平自动伸缩
## 启用 DNS 水平自动扩缩 {#enablng-dns-horizontal-autoscaling}
在本段,我们创建一个 Deployment。Deployment 中的 Pod 运行一个基于 `cluster-proportional-autoscaler-amd64` 镜像的容器。
在本节,我们创建一个 Deployment。Deployment 中的 Pod 运行一个基于
`cluster-proportional-autoscaler-amd64` 镜像的容器。
创建文件 `dns-horizontal-autoscaler.yaml`,内容如下所示:
{{< codenew file="admin/dns/dns-horizontal-autoscaler.yaml" >}}
在文件中,将 `<SCALE_TARGET>` 替换成 scale 目标。
<!--
In the file, replace `<SCALE_TARGET>` with your scale target.
Go to the directory that contains your configuration file, and enter this
command to create the Deployment:
-->
在文件中,将 `<SCALE_TARGET>` 替换成扩缩目标。
进入到包含配置文件的目录中,输入如下命令创建 Deployment
@ -215,46 +173,77 @@ DNS horizontal autoscaling is now enabled.
kubectl apply -f dns-horizontal-autoscaler.yaml
```
<!--
The output of a successful command is:
-->
一个成功的命令输出是:
deployment.apps/dns-autoscaler created
DNS 水平自动伸缩在已经启用了。
```
deployment.apps/dns-autoscaler created
```
<!--
## Tuning autoscaling parameters
DNS horizontal autoscaling is now enabled.
-->
DNS 水平自动扩缩在已经启用了。
<!--
## Tuning autoscaling parameters {#tuning-autoscaling-parameters}
Verify that the dns-autoscaler {{< glossary_tooltip text="ConfigMap" term_id="configmap" >}} exists:
-->
## 调优自动扩缩参数 {#tuning-autoscaling-parameters}
验证 dns-autoscaler {{< glossary_tooltip text="ConfigMap" term_id="configmap" >}} 是否存在:
```shell
kubectl get configmap --namespace=kube-system
```
<!--
The output is similar to this:
-->
输出类似于:
NAME DATA AGE
...
dns-autoscaler 1 ...
...
```
NAME DATA AGE
...
dns-autoscaler 1 ...
...
```
<!--
Modify the data in the ConfigMap:
-->
修改该 ConfigMap 中的数据:
```shell
kubectl edit configmap dns-autoscaler --namespace=kube-system
```
<!--
Look for this line:
-->
找到如下这行内容:
```yaml
linear: '{"coresPerReplica":256,"min":1,"nodesPerReplica":16}'
```
<!--
Modify the fields according to your needs. The "min" field indicates the
minimal number of DNS backends. The actual number of backends number is
calculated using this equation:
-->
replicas = max( ceil( cores * 1/coresPerReplica ) , ceil( nodes * 1/nodesPerReplica ) )
根据需要修改对应的字段。“min” 字段表明 DNS 后端的最小数量。
实际后端的数量通过使用如下公式来计算:
```
replicas = max( ceil( cores * 1/coresPerReplica ) , ceil( nodes * 1/nodesPerReplica ) )
```
<!--
Note that the values of both `coresPerReplica` and `nodesPerReplica` are
integers.
@ -265,42 +254,13 @@ cores, `nodesPerReplica` dominates.
There are other supported scaling patterns. For details, see
[cluster-proportional-autoscaler](https://github.com/kubernetes-incubator/cluster-proportional-autoscaler).
-->
## 调优自动伸缩参数
验证 dns-autoscaler {{< glossary_tooltip text="ConfigMap" term_id="configmap" >}} 是否存在:
```shell
kubectl get configmap --namespace=kube-system
```
输出类似如下所示:
NAME DATA AGE
...
dns-autoscaler 1 ...
...
修改该 ConfigMap 中的数据:
```shell
kubectl edit configmap dns-autoscaler --namespace=kube-system
```
找到如下这行内容:
```yaml
linear: '{"coresPerReplica":256,"min":1,"nodesPerReplica":16}'
```
根据需要修改对应的字段。“min” 字段说明 DNS 后端的最小数量。实际后端的数量,通过使用如下公式来计算:
replicas = max( ceil( cores * 1/coresPerReplica ) , ceil( nodes * 1/nodesPerReplica ) )
注意 `coresPerReplica``nodesPerReplica` 的值都是整数。
想法是,当一个集群使用具有很多核心的节点时,由 `coresPerReplica` 来控制。 当一个集群使用具有较少核心的节点时,由 `nodesPerReplica` 来控制。
背后的思想是,当一个集群使用具有很多核心的节点时,由 `coresPerReplica` 来控制。
当一个集群使用具有较少核心的节点时,由 `nodesPerReplica` 来控制。
其它的伸缩模式也是支持的,详情查看 [cluster-proportional-autoscaler](https://github.com/kubernetes-incubator/cluster-proportional-autoscaler)。
其它的扩缩模式也是支持的,详情查看
[cluster-proportional-autoscaler](https://github.com/kubernetes-incubator/cluster-proportional-autoscaler)。
<!--
## Disable DNS horizontal autoscaling
@ -308,37 +268,16 @@ linear: '{"coresPerReplica":256,"min":1,"nodesPerReplica":16}'
There are a few options for tuning DNS horizontal autoscaling. Which option to
use depends on different conditions.
-->
## 禁用 DNS 水平自动
## 禁用 DNS 水平自动
有几个 DNS 水平自动伸缩的选项。具体使用哪个选项因环境而异。
有几个可供调优的 DNS 水平自动扩缩选项。具体使用哪个选项因环境而异。
<!--
### Option 1: Scale down the dns-autoscaler deployment to 0 replicas
This option works for all situations. Enter this command:
```shell
kubectl scale deployment --replicas=0 dns-autoscaler --namespace=kube-system
```
The output is:
deployment.extensions/dns-autoscaler scaled
Verify that the replica count is zero:
```shell
kubectl get deployment --namespace=kube-system
```
The output displays 0 in the DESIRED and CURRENT columns:
NAME DESIRED CURRENT UP-TO-DATE AVAILABLE AGE
...
dns-autoscaler 0 0 0 0 ...
...
-->
### 选项 1调小 dns-autoscaler deployment 至 0 个副本
### 选项 1缩容 dns-autoscaler Deployment 至 0 个副本
该选项适用于所有场景。运行如下命令:
@ -346,48 +285,54 @@ The output displays 0 in the DESIRED and CURRENT columns:
kubectl scale deployment --replicas=0 dns-autoscaler --namespace=kube-system
```
<!-- The output is: -->
输出如下所示:
deployment.extensions/dns-autoscaler scaled
```
deployment.apps/dns-autoscaler scaled
```
<!--
Verify that the replica count is zero:
-->
验证当前副本数为 0
```shell
kubectl get deployment --namespace=kube-system
kubectl get rs --namespace=kube-system
```
<!--
The output displays 0 in the DESIRED and CURRENT columns:
-->
输出内容中,在 DESIRED 和 CURRENT 列显示为 0
NAME DESIRED CURRENT UP-TO-DATE AVAILABLE AGE
...
dns-autoscaler 0 0 0 0 ...
...
```
NAME DESIRED CURRENT READY AGE
...
dns-autoscaler-6b59789fc8 0 0 0 ...
...
```
<!--
### Option 2: Delete the dns-autoscaler deployment
This option works if dns-autoscaler is under your own control, which means
no one will re-create it:
```shell
kubectl delete deployment dns-autoscaler --namespace=kube-system
```
The output is:
deployment.extensions "dns-autoscaler" deleted
-->
### 选项 2删除 dns-autoscaler Deployment
如果 dns-autoscaler 为您所控制,该选项可以正常工作,也就说没有人会去重新创建它
如果 dns-autoscaler 为你所控制,也就说没有人会去重新创建它,可以选择此选项:
```shell
kubectl delete deployment dns-autoscaler --namespace=kube-system
```
<!-- The output is:-->
输出内容如下所示:
deployment.extensions "dns-autoscaler" deleted
```
deployment.apps "dns-autoscaler" deleted
```
<!--
### Option 3: Delete the dns-autoscaler manifest file from the master node
@ -395,27 +340,28 @@ kubectl delete deployment dns-autoscaler --namespace=kube-system
This option works if dns-autoscaler is under control of the (deprecated)
[Addon Manager](https://git.k8s.io/kubernetes/cluster/addons/README.md),
and you have write access to the master node.
-->
### 选项 3从主控节点删除 dns-autoscaler 清单文件
如果 dns-autoscaler 在[插件管理器](https://git.k8s.io/kubernetes/cluster/addons/README.md)
的控制之下,并且具有操作 master 节点的写权限,可以使用此选项。
<!--
Sign in to the master node and delete the corresponding manifest file.
The common path for this dns-autoscaler is:
-->
登录到主控节点,删除对应的清单文件。
dns-autoscaler 对应的路径一般为:
/etc/kubernetes/addons/dns-horizontal-autoscaler/dns-horizontal-autoscaler.yaml
```
/etc/kubernetes/addons/dns-horizontal-autoscaler/dns-horizontal-autoscaler.yaml
```
<!--
After the manifest file is deleted, the Addon Manager will delete the
dns-autoscaler Deployment.
-->
### 选项 3从 master 节点删除 dns-autoscaler manifest 文件
如果 dns-autoscaler 在[插件管理器](https://git.k8s.io/kubernetes/cluster/addons/README.md)的控制之下,该选项可以工作,并且具有操作 master 节点的写权限。
登录到 master 节点,删除对应的 manifest 文件。
dns-autoscaler 的路径一般为:
/etc/kubernetes/addons/dns-horizontal-autoscaler/dns-horizontal-autoscaler.yaml
当 manifest 文件删除后,插件管理器将删除 dns-autoscaler Deployment。
当清单文件被删除后,插件管理器将删除 dns-autoscaler Deployment。
<!-- discussion -->
@ -427,63 +373,45 @@ the DNS service.
* An autoscaler Pod runs a client that polls the Kubernetes API server for the
number of nodes and cores in the cluster.
-->
## 理解 DNS 水平自动扩缩工作原理
* cluster-proportional-autoscaler 应用独立于 DNS 服务部署。
* autoscaler Pod 运行一个客户端,它通过轮询 Kubernetes API 服务器获取集群中节点和核心的数量。
<!--
* A desired replica count is calculated and applied to the DNS backends based on
the current schedulable nodes and cores and the given scaling parameters.
* The scaling parameters and data points are provided via a ConfigMap to the
autoscaler, and it refreshes its parameters table every poll interval to be up
to date with the latest desired scaling parameters.
-->
* 系统会基于当前可调度的节点个数、核心数以及所给的扩缩参数,计算期望的副本数并应用到 DNS 后端。
* 扩缩参数和数据点会基于一个 ConfigMap 来提供给 autoscaler它会在每次轮询时刷新它的参数表
以与最近期望的扩缩参数保持一致。
<!--
* Changes to the scaling parameters are allowed without rebuilding or restarting
the autoscaler Pod.
* The autoscaler provides a controller interface to support two control
patterns: *linear* and *ladder*.
-->
## 理解 DNS 水平自动伸缩工作原理
* cluster-proportional-autoscaler 应用独立于 DNS service 部署。
* autoscaler Pod 运行一个客户端,它通过轮询 Kubernetes API server 获取集群中节点和核心的数量。
* 一个期望的副本数会被计算,并根据当前可调度的节点、核心数、给定伸缩参数,被应用到 DNS 后端。
* 伸缩参数和数据点会基于一个 ConfigMap 来提供给 autoscaler它会在每次轮询时刷新它的参数表以与最近期望的伸缩参数保持一致。
* 允许对伸缩参数进行修改,而不需要重建或重启 autoscaler Pod。
* 扩缩参数是可以被修改的,而且不需要重建或重启 autoscaler Pod。
* autoscaler 提供了一个控制器接口来支持两种控制模式:*linear* 和 *ladder*
<!--
## Future enhancements
Control patterns, in addition to linear and ladder, that consider custom metrics
are under consideration as a future development.
Scaling of DNS backends based on DNS-specific metrics is under consideration as
a future development. The current implementation, which uses the number of nodes
and cores in cluster, is limited.
Support for custom metrics, similar to that provided by
[Horizontal Pod Autoscaling](/docs/tasks/run-application/horizontal-pod-autoscale/),
is under consideration as a future development.
-->
## 未来功能增强
控制模式,除了 linear 和 ladder正在考虑未来将开发自定义 metric。
基于 DNS 特定 metric 的 DNS 后端的伸缩,考虑未来会开发。当前实现是使用集群中节点和核心的数量是受限制的。
支持自定义 metric类似于 [Horizontal Pod 自动伸缩](/docs/tasks/run-application/horizontal-pod-autoscale/) 所提供的,考虑未来进行开发。
## {{% heading "whatsnext" %}}
<!--
* Read about [Guaranteed Scheduling For Critical Add-On Pods](/docs/tasks/administer-cluster/guaranteed-scheduling-critical-addon-pods/).
* Learn more about the
[implementation of cluster-proportional-autoscaler](https://github.com/kubernetes-incubator/cluster-proportional-autoscaler).
-->
* 了解更多关于 [cluster-proportional-autoscaler 实现](https://github.com/kubernetes-incubator/cluster-proportional-autoscaler)的相关信息。
-->
* 阅读[为关键插件 Pod 提供的调度保障](/zh/docs/tasks/administer-cluster/guaranteed-scheduling-critical-addon-pods/)
* 进一步了解 [cluster-proportional-autoscaler 实现](https://github.com/kubernetes-incubator/cluster-proportional-autoscaler)