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Merge pull request #26298 from tengqm/zh-sync-connecting-fb

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[zh] Resync connecting-frontend-backend
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Kubernetes Prow Robot
2021-02-05 18:05:11 -08:00
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commit ce6620d46f
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content/zh/docs/tasks/access-application-cluster/connecting-frontend-backend.md
+90 -62
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@@ -3,31 +3,40 @@ title: 使用 Service 把前端连接到后端
content_type: tutorial
weight: 70
---
<!--
title: Connect a Frontend to a Backend Using Services
content_type: tutorial
weight: 70
-->
<!-- overview -->
<!--
This task shows how to create a frontend and a backend
microservice. The backend microservice is a hello greeter. The
frontend and backend are connected using a Kubernetes
{{< glossary_tooltip term_id="service" >}} object.
This task shows how to create a _frontend_ and a _backend_ microservice. The backend
microservice is a hello greeter. The frontend exposes the backend using nginx and a
Kubernetes {{< glossary_tooltip term_id="service" >}} object.
-->
本任务会描述如何创建前端微服务和后端微服务。后端微服务是一个 hello 欢迎程序。
前端和后端的连接是通过 Kubernetes {{< glossary_tooltip term_id="service" text="服务" >}}
完成的。
本任务会描述如何创建前端（Frontend）微服务和后端（Backend）微服务。后端微服务是一个 hello 欢迎程序。
前端通过 nginx 和一个 Kubernetes {{< glossary_tooltip term_id="service" text="服务" >}}
暴露后端所提供的服务。
## {{% heading "objectives" %}}
<!--
* Create and run a microservice using a {{< glossary_tooltip term_id="deployment" >}} object.
* Route traffic to the backend using a frontend.
* Use a Service object to connect the frontend application to the
backend application.
* Create and run a sample `hello` backend microservice using a
{{< glossary_tooltip term_id="deployment" >}} object.
* Use a Service object to send traffic to the backend microservice's multiple replicas.
* Create and run a `nginx` frontend microservice, also using a Deployment object.
* Configure the frontend microservice to send traffic to the backend microservice.
* Use a Service object of `type=LoadBalancer` to expose the frontend microservice
outside the cluster.
-->
* 使用部署对象（Deployment object）创建并运行一个微服务
* 从后端将流量路由到前端
* 使用服务对象把前端应用连接到后端应用
* 使用部署对象（Deployment object）创建并运行一个 `hello` 后端微服务
* 使用一个 Service 对象将请求流量发送到后端微服务的多个副本
* 同样使用一个 Deployment 对象创建并运行一个 `nginx` 前端微服务
* 配置前端微服务将请求流量发送到后端微服务
* 使用 `type=LoadBalancer` 的 Service 对象将全段微服务暴露到集群外部
## {{% heading "prerequisites" %}}
@@ -39,8 +48,7 @@ This task uses
require a supported environment. If your environment does not support this, you can use a Service of type
[NodePort](/docs/concepts/services-networking/service/#nodeport) instead.
-->
本任务使用 [外部负载均衡服务](/zh/docs/tasks/access-application-cluster/create-external-load-balancer/)，
本任务使用[外部负载均衡服务](/zh/docs/tasks/access-application-cluster/create-external-load-balancer/)，
所以需要对应的可支持此功能的环境。如果你的环境不能支持，你可以使用
[NodePort](/zh/docs/concepts/services-networking/service/#nodeport)
类型的服务代替。
@@ -57,7 +65,7 @@ file for the backend Deployment:
后端是一个简单的 hello 欢迎微服务应用。这是后端应用的 Deployment 配置文件：
{{< codenew file="service/access/hello.yaml" >}}
{{< codenew file="service/access/backend-deployment.yaml" >}}
<!--
Create the backend Deployment:
@@ -65,7 +73,7 @@ Create the backend Deployment:
创建后端 Deployment：
```shell
kubectl apply -f https://k8s.io/examples/service/access/hello.yaml
kubectl apply -f https://k8s.io/examples/service/access/backend-deployment.yaml
```
<!--
@@ -73,7 +81,7 @@ View information about the backend Deployment:
-->
查看后端的 Deployment 信息：
```
```shell
kubectl describe deployment hello
```
@@ -83,7 +91,7 @@ The output is similar to this:
输出类似于：
```
Name: hello
Name: backend
Namespace: default
CreationTimestamp: Mon, 24 Oct 2016 14:21:02 -0700
Labels: app=hello
@@ -91,7 +99,7 @@ Labels: app=hello
track=stable
Annotations: deployment.kubernetes.io/revision=1
Selector: app=hello,tier=backend,track=stable
Replicas: 7 desired | 7 updated | 7 total | 7 available | 0 unavailable
Replicas: 3 desired | 3 updated | 3 total | 3 available | 0 unavailable
StrategyType: RollingUpdate
MinReadySeconds: 0
RollingUpdateStrategy: 1 max unavailable, 1 max surge
@@ -112,15 +120,15 @@ Conditions:
Available True MinimumReplicasAvailable
Progressing True NewReplicaSetAvailable
OldReplicaSets: <none>
NewReplicaSet: hello-3621623197 (7/7 replicas created)
NewReplicaSet: hello-3621623197 (3/3 replicas created)
Events:
...
```
<!--
## Creating the backend Service object
## Creating the `hello` Service object
The key to connecting a frontend to a backend is the backend
The key to sending requests from a frontend to a backend is the backend
Service. A Service creates a persistent IP address and DNS name entry
so that the backend microservice can always be reached. A Service uses
{{< glossary_tooltip text="selectors" term_id="selector" >}} to find
@@ -128,68 +136,84 @@ the Pods that it routes traffic to.
First, explore the Service configuration file:
-->
### 创建后端服务对象
### 创建 `hello` Service 对象
前端连接到后端的关键是 Service（服务）。Service 创建一个固定 IP 和 DNS 解析名入口，
使得后端微服务可达。Service 使用
将请求从前端发送到到后端的关键是后端 Service。Service 创建一个固定 IP 和 DNS 解析名入口，
使得后端微服务总是可达。Service 使用
{{< glossary_tooltip text="选择算符" term_id="selector" >}}
来寻找目标 Pod。
首先，浏览 Service 的配置文件：
{{< codenew file="service/access/hello-service.yaml" >}}
{{< codenew file="service/access/backend-service.yaml" >}}
<!--
In the configuration file, you can see that the Service routes traffic to Pods
that have the labels `app: hello` and `tier: backend`.
In the configuration file, you can see that the Service named `hello` routes
traffic to Pods that have the labels `app: hello` and `tier: backend`.
-->
配置文件中，你可以看到 Service 将流量路由到包含 `app: hello` 和 `tier: backend` 标签的 Pod。
配置文件中，你可以看到名为 `hello` 的 Service 将流量路由到包含 `app: hello`
和 `tier: backend` 标签的 Pod。
<!--
Create the `hello` Service:
Create the backend Service:
-->
创建 `hello` Service：
创建后端 Service：
```shell
kubectl apply -f https://k8s.io/examples/service/access/hello-service.yaml
kubectl apply -f https://k8s.io/examples/service/access/backend-service.yaml
```
<!--
At this point, you have a backend Deployment running, and you have a
Service that can route traffic to it.
At this point, you have a `backend` Deployment running three replicas of your `hello`
application, and you have a Service that can route traffic to them. However, this
service is neither available nor resolvable outside the cluster.
-->
此时，你已经有了一个在运行的后端 Deployment，你也有了一个 Service 用于路由网络流量。
此时，你已经有了一个运行着 `hello` 应用的三个副本的 `backend` Deployment，你也有了
一个 Service 用于路由网络流量。不过，这个服务在集群外部无法访问也无法解析。
<!--
## Creating the frontend
Now that you have your backend, you can create a frontend that connects to the backend.
The frontend connects to the backend worker Pods by using the DNS name
given to the backend Service. The DNS name is "hello", which is the value
of the `name` field in the preceding Service configuration file.
Now that you have your backend running, you can create a frontend that is accessible
outside the cluster, and connects to the backend by proxying requests to it.
The frontend sends requests to the backend worker Pods by using the DNS name
given to the backend Service. The DNS name is `hello`, which is the value
of the `name` field in the `examples/service/access/backend-service.yaml`
configuration file.
The Pods in the frontend Deployment run an nginx image that is configured
to find the hello backend Service. Here is the nginx configuration file:
to proxy requests to the hello backend Service. Here is the nginx configuration file:
-->
### 创建前端应用
既然你已经有了后端应用，你可以创建一个前端应用连接到后端。前端应用通过 DNS 名连接到后端的工作 Pods。
DNS 名是 "hello"，也就是 Service 配置文件中 `name` 字段的值。
现在你已经有了运行中的后端应用，你可以创建一个可在集群外部访问的前端，并通过代理
前端的请求连接到后端。
前端 Deployment 中的 Pods 运行一个 nginx 镜像，这个已经配置好镜像去寻找后端的 hello Service。
只是 nginx 的配置文件：
前端使用被赋予后端 Service 的 DNS 名称将请求发送到后端工作 Pods。这一 DNS
名称为 `hello`，也就是 `examples/service/access/backend-service.yaml` 配置
文件中 `name` 字段的取值。
{{< codenew file="service/access/frontend.conf" >}}
前端 Deployment 中的 Pods 运行一个 nginx 镜像，这个已经配置好的镜像会将请求转发
给后端的 hello Service。下面是 nginx 的配置文件：
{{< codenew file="service/access/frontend-nginx.conf" >}}
<!--
Similar to the backend, the frontend has a Deployment and a Service. The
configuration for the Service has `type: LoadBalancer`, which means that
the Service uses the default load balancer of your cloud provider.
Similar to the backend, the frontend has a Deployment and a Service. An important
difference to notice between the backend and frontend services, is that the
configuration for the frontend Service has `type: LoadBalancer`, which means that
the Service uses a load balancer provisioned by your cloud provider and will be
accessible from outside the cluster.
-->
与后端类似，前端用包含一个 Deployment 和一个 Service。Service 的配置文件包含了 `type: LoadBalancer`，
也就是说，Service 会使用你的云服务商的默认负载均衡设备。
与后端类似，前端用包含一个 Deployment 和一个 Service。后端与前端服务之间的一个
重要区别是前端 Service 的配置文件包含了 `type: LoadBalancer`，也就是说，Service
会使用你的云服务商的默认负载均衡设备，从而实现从集群外访问的目的。
{{< codenew file="service/access/frontend-service.yaml" >}}
{{< codenew file="service/access/frontend-deployment.yaml" >}}
{{< codenew file="service/access/frontend.yaml" >}}
<!--
Create the frontend Deployment and Service:
@@ -197,7 +221,8 @@ Create the frontend Deployment and Service:
创建前端 Deployment 和 Service：
```shell
kubectl apply -f https://k8s.io/examples/service/access/frontend.yaml
kubectl apply -f https://k8s.io/examples/service/access/frontend-deployment.yaml
kubectl apply -f https://k8s.io/examples/service/access/frontend-service.yaml
```
<!--
@@ -271,21 +296,22 @@ cluster.
<!--
## Send traffic through the frontend
The frontend and backends are now connected. You can hit the endpoint
The frontend and backend are now connected. You can hit the endpoint
by using the curl command on the external IP of your frontend Service.
-->
### 通过前端发送流量
前端和后端已经完成连接了。你可以使用 curl 命令通过你的前端 Service 的外部 IP 访问服务端点。
前端和后端已经完成连接了。你可以使用 curl 命令通过你的前端 Service 的外部
IP 访问服务端点。
```shell
curl http://<EXTERNAL-IP>
curl http://${EXTERNAL_IP} # 将 EXTERNAL_P 替换为你之前看到的外部 IP
```
<!--
The output shows the message generated by the backend:
-->
后端生成的消息输出如下：
输出显示后端生成的消息：
```json
{"message":"Hello"}
@@ -299,7 +325,7 @@ To delete the Services, enter this command:
要删除服务，输入下面的命令：
```shell
kubectl delete services frontend hello
kubectl delete services frontend backend
```
<!--
@@ -308,14 +334,16 @@ To delete the Deployments, the ReplicaSets and the Pods that are running the bac
要删除在前端和后端应用中运行的 Deployment、ReplicaSet 和 Pod，输入下面的命令：
```shell
kubectl delete deployment frontend hello
kubectl delete deployment frontend backend
```
## {{% heading "whatsnext" %}}
<!--
* Learn more about [Services](/docs/concepts/services-networking/service/)
* Learn more about [ConfigMaps](/docs/tasks/configure-pod-container/configure-pod-configmap/)
* Learn more about [DNS for Service and Pods](/docs/concepts/services-networking/dns-pod-service/)
-->
* 进一步了解[Service](/zh/docs/concepts/services-networking/service/)
* 进一步了解[ConfigMap](/zh/docs/tasks/configure-pod-container/configure-pod-configmap/)
* 进一步了解 [Service](/zh/docs/concepts/services-networking/service/)
* 进一步了解 [ConfigMap](/zh/docs/tasks/configure-pod-container/configure-pod-configmap/)
* 进一步了解 [Service 和 Pods 的 DNS](/docs/concepts/services-networking/dns-pod-service/)