237 lines
7.7 KiB
Markdown
237 lines
7.7 KiB
Markdown
---
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title: 使用服务来访问集群中的应用
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content_template: templates/tutorial
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weight: 60
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---
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<!--
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---
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title: Use a Service to Access an Application in a Cluster
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content_template: templates/tutorial
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weight: 60
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---
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-->
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{{% capture overview %}}
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<!--
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This page shows how to create a Kubernetes Service object that external
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clients can use to access an application running in a cluster. The Service
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provides load balancing for an application that has two running instances.
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-->
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本文展示如何创建一个 Kubernetes 服务对象，能让外部客户端访问在集群中运行的应用。该服务为一个应用的两个运行实例提供负载均衡。
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{{% /capture %}}
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{{% capture prerequisites %}}
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{{< include "task-tutorial-prereqs.md" >}} {{< version-check >}}
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{{% /capture %}}
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{{% capture objectives %}}
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<!--
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* Run two instances of a Hello World application.
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* Create a Service object that exposes a node port.
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* Use the Service object to access the running application.
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-->
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* 运行 Hello World 应用的两个实例。
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* 创建一个服务对象来暴露 node port。
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* 使用服务对象来访问正在运行的应用。
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{{% /capture %}}
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{{% capture lessoncontent %}}
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<!--
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## Creating a service for an application running in two pods
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Here is the configuration file for the application Deployment:
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-->
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## 为运行在两个 pod 中的应用创建一个服务
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这是应用程序部署的配置文件：
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{{< codenew file="service/access/hello-application.yaml" >}}
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<!--
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1. Run a Hello World application in your cluster:
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Create the application Deployment using the file above:
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```shell
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kubectl apply -f https://k8s.io/examples/service/access/hello-application.yaml
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```
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The preceding command creates a
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[Deployment](/docs/concepts/workloads/controllers/deployment/)
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object and an associated
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[ReplicaSet](/docs/concepts/workloads/controllers/replicaset/)
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object. The ReplicaSet has two
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[Pods](/docs/concepts/workloads/pods/pod/),
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each of which runs the Hello World application.
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-->
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1. 在您的集群中运行一个 Hello World 应用：
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使用上面的文件创建应用程序 Deployment：
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```shell
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kubectl apply -f https://k8s.io/examples/service/access/hello-application.yaml
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```
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上面的命令创建一个 [Deployment](/docs/concepts/workloads/controllers/deployment/) 对象和一个关联的 [ReplicaSet](/docs/concepts/workloads/controllers/replicaset/) 对象。这个 ReplicaSet 有两个 [Pod](/docs/concepts/workloads/pods/pod/)，每个 Pod 都运行着 Hello World 应用。
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<!--
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1. Display information about the Deployment:
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-->
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1. 展示 Deployment 的信息：
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```shell
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kubectl get deployments hello-world
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kubectl describe deployments hello-world
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```
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<!--
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1. Display information about your ReplicaSet objects:
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-->
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1. 展示您的 ReplicaSet 对象信息：
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```shell
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kubectl get replicasets
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kubectl describe replicasets
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```
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<!--
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1. Create a Service object that exposes the deployment:
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-->
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1. 创建一个服务对象来暴露 deployment：
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```shell
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kubectl expose deployment hello-world --type=NodePort --name=example-service
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```
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<!--
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1. Display information about the Service:
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-->
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1. 展示服务信息：
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```shell
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kubectl describe services example-service
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```
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<!--
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The output is similar to this:
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-->
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输出类似于：
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```shell
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Name: example-service
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Namespace: default
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Labels: run=load-balancer-example
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Annotations: <none>
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Selector: run=load-balancer-example
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Type: NodePort
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IP: 10.32.0.16
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Port: <unset> 8080/TCP
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TargetPort: 8080/TCP
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NodePort: <unset> 31496/TCP
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Endpoints: 10.200.1.4:8080,10.200.2.5:8080
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Session Affinity: None
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Events: <none>
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```
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<!--
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Make a note of the NodePort value for the service. For example,
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in the preceding output, the NodePort value is 31496.
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-->
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注意服务中的 NodePort 值。例如在上面的输出中，NodePort 是 31496。
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<!--
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1. List the pods that are running the Hello World application:
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-->
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1. 列出运行 Hello World 应用的 pod：
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```shell
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kubectl get pods --selector="run=load-balancer-example" --output=wide
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```
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<!--
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The output is similar to this:
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-->
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输出类似于：
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```shell
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NAME READY STATUS ... IP NODE
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hello-world-2895499144-bsbk5 1/1 Running ... 10.200.1.4 worker1
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hello-world-2895499144-m1pwt 1/1 Running ... 10.200.2.5 worker2
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```
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<!--
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1. Get the public IP address of one of your nodes that is running
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a Hello World pod. How you get this address depends on how you set
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up your cluster. For example, if you are using Minikube, you can
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see the node address by running `kubectl cluster-info`. If you are
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using Google Compute Engine instances, you can use the
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`gcloud compute instances list` command to see the public addresses of your
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nodes.
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1. On your chosen node, create a firewall rule that allows TCP traffic
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on your node port. For example, if your Service has a NodePort value of
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31568, create a firewall rule that allows TCP traffic on port 31568. Different
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cloud providers offer different ways of configuring firewall rules.
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1. Use the node address and node port to access the Hello World application:
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-->
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1. 获取运行 Hello World 的 pod 的其中一个节点的公共 IP 地址。如何获得此地址取决于您设置集群的方式。
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例如，如果您使用的是 Minikube，则可以通过运行 `kubectl cluster-info` 来查看节点地址。
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如果您使用的是 Google Compute Engine 实例，则可以使用 `gcloud compute instances list` 命令查看节点的公共地址。
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1. 在您选择的节点上，创建一个防火墙规则以开放 node port 上的 TCP 流量。
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例如，如果您的服务的 NodePort 值为 31568，请创建一个防火墙规则以允许 31568 端口上的 TCP 流量。
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不同的云提供商提供了不同方法来配置防火墙规则。
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1. 使用节点地址和 node port 来访问 Hello World 应用：
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```shell
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curl http://<public-node-ip>:<node-port>
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```
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<!--
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where `<public-node-ip>` is the public IP address of your node,
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and `<node-port>` is the NodePort value for your service. The
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response to a successful request is a hello message:
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-->
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这里的 `<public-node-ip>` 是您节点的公共 IP 地址，`<node-port>` 是您服务的 NodePort 值。
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对于请求成功的响应是一个 hello 消息：
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```shell
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Hello Kubernetes!
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```
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<!--
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## Using a service configuration file
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As an alternative to using `kubectl expose`, you can use a
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[service configuration file](/docs/concepts/services-networking/service/)
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to create a Service.
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-->
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## 使用服务配置文件
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作为 `kubectl expose` 的替代方法，您可以使用 [服务配置文件](/docs/concepts/services-networking/service/) 来创建服务。
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{{% /capture %}}
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{{% capture cleanup %}}
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<!--
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To delete the Service, enter this command:
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-->
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想要删除服务，输入以下命令：
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kubectl delete services example-service
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<!--
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To delete the Deployment, the ReplicaSet, and the Pods that are running
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the Hello World application, enter this command:
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-->
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想要删除运行 Hello World 应用的 Deployment、ReplicaSet 和 Pod，输入以下命令：
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kubectl delete deployment hello-world
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{{% /capture %}}
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{{% capture whatsnext %}}
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<!--
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Learn more about
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[connecting applications with services](/docs/concepts/services-networking/connect-applications-service/).
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-->
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学习更多关于如何 [通过服务连接应用](/docs/concepts/services-networking/connect-applications-service/)。
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{{% /capture %}}
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