本文大綱
接下來的內容由以下幾部分組成：
- 什麼是SpringCloud Gateway
- SpringCloud Gateway實戰參考
- kubernetes上的SpringCloud Gateway
- 實戰環境信息
- 實戰源碼下載
- 開發webdemo
- 開發k8sgatewaydemo
- 解決權限問題
- 最後一個疑問
什麼是SpringCloud Gateway
SpringCloud Gateway是SpringCloud技術棧下的網關服務框架，在基於SpringCloud的微服務環境中，外部請求會到達SpringCloud Gateway應用，該應用對請求做轉發、過濾、鑑權、熔斷等前置操作，一個典型的請求響應流程如下所示：
SpringCloud Gateway實戰參考
如果您之前沒有使用過SpringCloud Gateway，推薦您閱讀《速體驗SpringCloud Gateway》，有時間的話動手實戰效果更佳，只需編寫少量代碼就能快速熟悉這個SpringCloud技術棧中非常重要的功能；
kubernetes上的SpringCloud Gateway
注意以下兩個知識點：
- SpringCloud Gateway之所以能將外部請求路由到正確的後臺服務上，是因爲註冊中心的存在，SpringCloud Gateway可以在註冊中心取得所有服務的信息，因此它可以根據路徑和服務的對應關係，將請求轉發到對應的服務上；
- 如果您看過本系列的上一篇 《spring-cloud-kubernetes的服務發現和輪詢實戰(含熔斷)》，您就知道spring-cloud-kubernetes框架可以獲取kubernetes環境內的所有服務（這裏說的服務就是kubernetes的service）；
將以上兩個知識點結合起來，於是可以推測：運行在kubernetes環境的SpringCloud Gateway應用，如果使用了spring-cloud-kubernetes框架就能得到kubernetes的service列表，因此可以承擔網關的角色，將外部請求轉發至kubernetes內的service上，最終到達對應的Pod；
架構如下圖所示，請注意黃色背景的對話框，裏面標識了關鍵操作：
至此，理論分析已經完成，我們來實戰驗證這個理論，接下來我們開發兩個java應用：
- 先開發一個普通的web服務，名爲webdemo，提供一個http接口；
- 再開發一個SpringCloud Gateway應用，名爲k8sgatewaydemo；
環境信息
本次實戰的環境和版本信息如下：
- 操作系統：CentOS Linux release 7.6.1810
- minikube：1.1.1
- Java：1.8.0_191
- Maven：3.6.0
- fabric8-maven-plugin插件：3.5.37
- spring-cloud-kubernetes：1.0.1.RELEASE
- spring cloud：Greenwich.SR2
- springboot：2.1.6.RELEASE
源碼下載
如果您不打算寫代碼，也可以從GitHub上下載本次實戰的源碼，地址和鏈接信息如下表所示：
|
名稱 |
鏈接 |
備註 |
|---|---|---|
|
項目主頁 |
https://github.com/zq2599/blog_demos
|
該項目在GitHub上的主頁 |
|
git倉庫地址(https) |
https://github.com/zq2599/blog_demos.git |
該項目源碼的倉庫地址，https協議 |
|
git倉庫地址(ssh) |
[email protected]:zq2599/blog_demos.git |
該項目源碼的倉庫地址，ssh協議 |
這個git項目中有多個文件夾，本章的兩個應用分別在webdemo和k8sgatewaydemo文件夾下； 下圖紅框中是webdemo應用的源碼：
下圖紅框中是k8sgatewaydemo應用的源碼：
下面是詳細的編碼過程；
開發webdemo
webdemo是個極其普通的spring boot應用，和SpringCloud沒有任何關係；
- webdemo提供一個http接口，將請求header中名爲extendtag的參數返回給請求方，controller類如下：
@RestController
@RequestMapping("/hello")
public class HelloController {
@RequestMapping(value = "time", method = RequestMethod.GET)
public String hello(HttpServletRequest request){
return "hello, "
+ new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(new Date())
+ ", extendtag ["
+ request.getHeader("extendtag")
+ "]";
}
}
- 啓動類WebdemoApplication.java：
@SpringBootApplication
public class WebdemoApplication {
public static void main(String[] args) {
SpringApplication.run(WebdemoApplication.class, args);
}
}
- 要注意的是pom.xml，裏面通過名爲fabric8-maven-plugin的maven插件，將webdemo快速部署到minikube環境：
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.1.6.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<groupId>com.bolingcavalry</groupId>
<artifactId>webdemo</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>webdemo</name>
<description>Demo project for Spring Boot</description>
<properties>
<java.version>1.8</java.version>
<spring-boot.version>2.1.6.RELEASE</spring-boot.version>
<fabric8.maven.plugin.version>3.5.37</fabric8.maven.plugin.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
<version>${spring-boot.version}</version>
<executions>
<execution>
<goals>
<goal>repackage</goal>
</goals>
</execution>
</executions>
</plugin>
<plugin>
<!--skip deploy -->
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-deploy-plugin</artifactId>
<version>${maven-deploy-plugin.version}</version>
<configuration>
<skip>true</skip>
</configuration>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-surefire-plugin</artifactId>
<version>${maven-surefire-plugin.version}</version>
<configuration>
<skipTests>true</skipTests>
<!-- Workaround for https://issues.apache.org/jira/browse/SUREFIRE-1588 -->
<useSystemClassLoader>false</useSystemClassLoader>
</configuration>
</plugin>
<plugin>
<groupId>io.fabric8</groupId>
<artifactId>fabric8-maven-plugin</artifactId>
<version>${fabric8.maven.plugin.version}</version>
<executions>
<execution>
<id>fmp</id>
<goals>
<goal>resource</goal>
</goals>
</execution>
</executions>
</plugin>
</plugins>
</build>
<profiles>
<profile>
<id>kubernetes</id>
<build>
<plugins>
<plugin>
<groupId>io.fabric8</groupId>
<artifactId>fabric8-maven-plugin</artifactId>
<version>${fabric8.maven.plugin.version}</version>
<executions>
<execution>
<id>fmp</id>
<goals>
<goal>resource</goal>
<goal>build</goal>
</goals>
</execution>
</executions>
<configuration>
<enricher>
<config>
<fmp-service>
<type>NodePort</type>
</fmp-service>
</config>
</enricher>
</configuration>
</plugin>
</plugins>
</build>
</profile>
</profiles>
</project>
- 以上就是webdemo應用的內容了，接下來要編譯、構建、部署到minikube環境，在pom.xml執行以下命令即可：
mvn clean install fabric8:deploy -Dfabric8.generator.from=fabric8/java-jboss-openjdk8-jdk -Pkubernetes
部署完成後終端輸出類似如下成功信息：
[INFO] [INFO] <<< fabric8-maven-plugin:3.5.37:deploy (default-cli) < install @ webdemo <<< [INFO] [INFO] [INFO] --- fabric8-maven-plugin:3.5.37:deploy (default-cli) @ webdemo --- [INFO] F8: Using Kubernetes at https://192.168.121.133:8443/ in namespace default with manifest /usr/local/work/k8s/webdemo/target/classes/META-INF/fabric8/kubernetes.yml [INFO] Using namespace: default [INFO] Updating a Service from kubernetes.yml [INFO] Updated Service: target/fabric8/applyJson/default/service-webdemo.json [INFO] Using namespace: default [INFO] Updating Deployment from kubernetes.yml [INFO] Updated Deployment: target/fabric8/applyJson/default/deployment-webdemo.json [INFO] F8: HINT: Use the command `kubectl get pods -w` to watch your pods start up [INFO] ------------------------------------------------------------------------ [INFO] BUILD SUCCESS [INFO] ------------------------------------------------------------------------ [INFO] Total time: 11.804 s [INFO] Finished at: 2019-07-07T21:32:26+08:00 [INFO] ------------------------------------------------------------------------
- 查看service和pod，確認一切正常：
[root@minikube webdemo]# kubectl get service NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 29d webdemo NodePort 10.106.98.137 <none> 8080:30160/TCP 115m [root@minikube webdemo]# kubectl get pod NAME READY STATUS RESTARTS AGE webdemo-c9f774b9-gsbgx 1/1 Running 0 3m13s
- 使用minikube命令取得webdemo服務對外暴露的地址：
[root@minikube webdemo]# minikube service webdemo --url http://192.168.121.133:30160
可見外部通過地址：http://192.168.121.133:30160 即可訪問到webdemo應用； 7. 在瀏覽器輸入地址：http://192.168.121.133:30160/hello/time ，即可驗證webdemo的http接口是否正常，如下圖，由於header中沒有extendtag屬性，因此返回的extendtag爲null：
至此，webdemo在minikue上已經正常運行，該開發gateway應用了；
開發k8sgatewaydemo
- 基於maven創建一個名爲k8sgatewaydemo的springboot應用，pom.xml內容如下：
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.1.6.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<groupId>com.bolingcavalry</groupId>
<artifactId>k8sgatewaydemo</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>k8sgatewaydemo</name>
<description>Demo project for Spring Boot</description>
<properties>
<java.version>1.8</java.version>
<spring-boot.version>2.1.6.RELEASE</spring-boot.version>
<maven-checkstyle-plugin.failsOnError>false</maven-checkstyle-plugin.failsOnError>
<maven-checkstyle-plugin.failsOnViolation>false</maven-checkstyle-plugin.failsOnViolation>
<maven-checkstyle-plugin.includeTestSourceDirectory>false</maven-checkstyle-plugin.includeTestSourceDirectory>
<maven-compiler-plugin.version>3.5</maven-compiler-plugin.version>
<maven-deploy-plugin.version>2.8.2</maven-deploy-plugin.version>
<maven-failsafe-plugin.version>2.18.1</maven-failsafe-plugin.version>
<maven-surefire-plugin.version>2.21.0</maven-surefire-plugin.version>
<fabric8.maven.plugin.version>3.5.37</fabric8.maven.plugin.version>
<springcloud.kubernetes.version>1.0.1.RELEASE</springcloud.kubernetes.version>
<spring-cloud.version>Greenwich.SR2</spring-cloud.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-gateway</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-kubernetes-core</artifactId>
<version>${springcloud.kubernetes.version}</version>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-kubernetes-discovery</artifactId>
<version>${springcloud.kubernetes.version}</version>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-kubernetes-ribbon</artifactId>
<version>${springcloud.kubernetes.version}</version>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-commons</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-netflix-ribbon</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-netflix-hystrix</artifactId>
</dependency>
</dependencies>
<dependencyManagement>
<dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-dependencies</artifactId>
<version>${spring-cloud.version}</version>
<type>pom</type>
<scope>import</scope>
</dependency>
</dependencies>
</dependencyManagement>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
<version>${spring-boot.version}</version>
<executions>
<execution>
<goals>
<goal>repackage</goal>
</goals>
</execution>
</executions>
</plugin>
<plugin>
<!--skip deploy -->
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-deploy-plugin</artifactId>
<version>${maven-deploy-plugin.version}</version>
<configuration>
<skip>true</skip>
</configuration>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-surefire-plugin</artifactId>
<version>${maven-surefire-plugin.version}</version>
<configuration>
<skipTests>true</skipTests>
<!-- Workaround for https://issues.apache.org/jira/browse/SUREFIRE-1588 -->
<useSystemClassLoader>false</useSystemClassLoader>
</configuration>
</plugin>
<plugin>
<groupId>io.fabric8</groupId>
<artifactId>fabric8-maven-plugin</artifactId>
<version>${fabric8.maven.plugin.version}</version>
<executions>
<execution>
<id>fmp</id>
<goals>
<goal>resource</goal>
</goals>
</execution>
</executions>
</plugin>
</plugins>
</build>
<profiles>
<profile>
<id>kubernetes</id>
<build>
<plugins>
<plugin>
<groupId>io.fabric8</groupId>
<artifactId>fabric8-maven-plugin</artifactId>
<version>${fabric8.maven.plugin.version}</version>
<executions>
<execution>
<id>fmp</id>
<goals>
<goal>resource</goal>
<goal>build</goal>
</goals>
</execution>
</executions>
<configuration>
<enricher>
<config>
<fmp-service>
<type>NodePort</type>
</fmp-service>
</config>
</enricher>
</configuration>
</plugin>
</plugins>
</build>
</profile>
</profiles>
</project>
上述pom文件中有以下幾點需要注意： 第一、 依賴spring-cloud-kubernetes-core和spring-cloud-kubernetes-discovery，這樣能用到spring-cloud-kubernetes提供的服務發現能力； 第二、依賴spring-cloud-starter-gateway，這樣能用上SpringCloud的gateway能力； 第三、不要依賴spring-boot-starter-web，會和spring-cloud-starter-gateway衝突，啓動時拋出以下異常：
2019-07-06 08:12:09.188 WARN 1 --- [ main] ConfigServletWebServerApplicationContext :
Exception encountered during context initialization -
cancelling refresh attempt:
org.springframework.beans.factory.UnsatisfiedDependencyException:
Error creating bean with name 'routeDefinitionRouteLocator' defined in class path resource [org/springframework/cloud/gateway/config/GatewayAutoConfiguration.class]:
Unsatisfied dependency expressed through method 'routeDefinitionRouteLocator' parameter 1;
nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException:
Error creating bean with name 'modifyRequestBodyGatewayFilterFactory' defined in class path resource [org/springframework/cloud/gateway/config/GatewayAutoConfiguration.class]:
Unsatisfied dependency expressed through method 'modifyRequestBodyGatewayFilterFactory' parameter 0;
nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type 'org.springframework.http.codec.ServerCodecConfigurer' available:
expected at least 1 bean which qualifies as autowire candidate. Dependency annotations: {}
- 開發SpringCloud Gateway的啓動類K8sgatewaydemoApplication.java，裏面也包含了網關路由配置的實例化，除了配置路徑和轉發服務的關係，還在請求的header中添加了extendtag屬性，請注意註釋的內容：
@SpringBootApplication
@EnableDiscoveryClient
public class K8sgatewaydemoApplication {
public static void main(String[] args) {
SpringApplication.run(K8sgatewaydemoApplication.class, args);
}
@Bean
public RouteLocator customRouteLocator(RouteLocatorBuilder builder) {
return builder.routes()
//增加一個path匹配，以"/customize/hello/"開頭的請求都在此路由
.route(r -> r.path("/customize/hello/**")
//表示將路徑中的第一級參數刪除，用剩下的路徑與webdemo的路徑做拼接，
//這裏就是"lb://webdemo/hello/"，能匹配到webdemo的HelloController的路徑
.filters(f -> f.stripPrefix(1)
//在請求的header中添加一個key&value
.addRequestHeader("extendtag", "geteway-" + System.currentTimeMillis()))
//指定匹配服務webdemo，lb是load balance的意思
.uri("lb://webdemo")
).build();
}
}
從上述代碼可見，K8sgatewaydemoApplication與普通環境下的SpringCloud Gateway並無差別，都是通過EnableDiscoveryClient註解獲取服務列表，配置RouteLocator實現路由邏輯； 3. 配置文件application.yml的內容：
spring:
application:
name: gateway
cloud:
gateway:
discovery:
locator:
enabled: true
lowerCaseServiceId: true
- 以上就是k8sgatewaydemo應用的內容了，接下來要編譯、構建、部署到minikube環境，在pom.xml執行以下命令即可：
mvn clean install fabric8:deploy -Dfabric8.generator.from=fabric8/java-jboss-openjdk8-jdk -Pkubernetes
部署完成後終端輸出類似如下成功信息：
[INFO] [INFO] <<< fabric8-maven-plugin:3.5.37:deploy (default-cli) < install @ k8sgatewaydemo <<< [INFO] [INFO] [INFO] --- fabric8-maven-plugin:3.5.37:deploy (default-cli) @ k8sgatewaydemo --- [INFO] F8: Using Kubernetes at https://192.168.121.133:8443/ in namespace default with manifest /usr/local/work/k8s/k8sgatewaydemo/target/classes/META-INF/fabric8/kubernetes.yml [INFO] Using namespace: default [INFO] Updating a Service from kubernetes.yml [INFO] Updated Service: target/fabric8/applyJson/default/service-k8sgatewaydemo.json [INFO] Using namespace: default [INFO] Updating Deployment from kubernetes.yml [INFO] Updated Deployment: target/fabric8/applyJson/default/deployment-k8sgatewaydemo.json [INFO] F8: HINT: Use the command `kubectl get pods -w` to watch your pods start up [INFO] ------------------------------------------------------------------------ [INFO] BUILD SUCCESS [INFO] ------------------------------------------------------------------------ [INFO] Total time: 16.538 s [INFO] Finished at: 2019-07-07T22:04:48+08:00 [INFO] ------------------------------------------------------------------------
- 查看service和pod，確認一切正常：
[root@minikube k8sgatewaydemo]# clear [root@minikube k8sgatewaydemo]# kubectl get service NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE k8sgatewaydemo NodePort 10.97.94.238 <none> 8080:31352/TCP 129m kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 29d webdemo NodePort 10.106.98.137 <none> 8080:30160/TCP 145m [root@minikube k8sgatewaydemo]# kubectl get pod NAME READY STATUS RESTARTS AGE k8sgatewaydemo-6fbb79885c-r2jfn 1/1 Running 0 33s webdemo-c9f774b9-gsbgx 1/1 Running 0 32m
- 使用minikube命令取得webdemo服務對外暴露的地址：
[root@minikube k8sgatewaydemo]# minikube service k8sgatewaydemo --url http://192.168.121.133:31352
可見外部通過地址：http://192.168.121.133:31352 即可訪問到k8sgatewaydemo應用； 7. 在瀏覽器輸入地址：http://192.168.121.133:31352/customize/hello/time ，即可驗證k8sgatewaydemo作爲網關應用，能否將路徑中帶有customize的請求轉發到webdemo應用，並且在請求header中添加名爲entendtag的屬性，如下圖，瀏覽器展示的內容是webdemo的http接口返回的，並且extendtag的內容也不爲空了，而是k8sgatewaydemo在轉發前寫入的：
上述結果表明已可以證明我們之前的推測是正確的：SpringCloud Gateway應用在使用了spring-cloud-kubernetes提供的註冊發現能力後，可以將請求轉發到kubernetes環境中的服務上； 也就是說，藉助spring-cloud-kubernetes框架，你在SpringCloud環境開發的SpringCloud Gateway應用，可以以很小的代價遷移到kubernetes環境，與kubernetes環境中的service可以很好的交互，而原有的eureka註冊中心也可以不用了；
解決權限問題
如果您的spring-cloud-kubernetes在向webdemo轉發請求時拋出以下錯誤，那是因爲遇到了kubernetes的權限問題：
2019-07-06 04:46:40.042 WARN 1 --- [erListUpdater-1] c.n.l.PollingServerListUpdater : Failed one update cycle
io.fabric8.kubernetes.client.KubernetesClientException: Failure executing: GET at: https://10.96.0.1/api/v1/namespaces/default/endpoints/account-service. Message: Forbidden!Configured service account doesn't have access. Service account may have been revoked. endpoints "account-service" is forbidden: User "system:serviceaccount:default:default" cannot get resource "endpoints" in API group "" in the namespace "default".
at io.fabric8.kubernetes.client.dsl.base.OperationSupport.requestFailure(OperationSupport.java:476) ~[kubernetes-client-4.1.0.jar!/:na]
at io.fabric8.kubernetes.client.dsl.base.OperationSupport.assertResponseCode(OperationSupport.java:413) ~[kubernetes-client-4.1.0.jar!/:na]
at io.fabric8.kubernetes.client.dsl.base.OperationSupport.handleResponse(OperationSupport.java:381) ~[kubernetes-client-4.1.0.jar!/:na]
at io.fabric8.kubernetes.client.dsl.base.OperationSupport.handleResponse(OperationSupport.java:344) ~[kubernetes-client-4.1.0.jar!/:na]
at io.fabric8.kubernetes.client.dsl.base.OperationSupport.handleGet(OperationSupport.java:313) ~[kubernetes-client-4.1.0.jar!/:na]
at io.fabric8.kubernetes.client.dsl.base.OperationSupport.handleGet(OperationSupport.java:296) ~[kubernetes-client-4.1.0.jar!/:na]
at io.fabric8.kubernetes.client.dsl.base.BaseOperation.handleGet(BaseOperation.java:794) ~[kubernetes-client-4.1.0.jar!/:na]
at io.fabric8.kubernetes.client.dsl.base.BaseOperation.getMandatory(BaseOperation.java:210) ~[kubernetes-client-4.1.0.jar!/:na]
at io.fabric8.kubernetes.client.dsl.base.BaseOperation.get(BaseOperation.java:177) ~[kubernetes-client-4.1.0.jar!/:na]
at org.springframework.cloud.kubernetes.ribbon.KubernetesServerList
.getUpdatedListOfServers(KubernetesServerList.java:75) ~[spring-cloud-kubernetes-ribbon-1.0.1.RELEASE.jar!/:1.0.1.RELEASE]
at com.netflix.loadbalancer.DynamicServerListLoadBalancer.updateListOfServers(DynamicServerListLoadBalancer.java:240) ~[ribbon-loadbalancer-2.3.0.jar!/:2.3.0]
at com.netflix.loadbalancer.DynamicServerListLoadBalancer$1.doUpdate(DynamicServerListLoadBalancer.java:62) ~[ribbon-loadbalancer-2.3.0.jar!/:2.3.0]
at com.netflix.loadbalancer.PollingServerListUpdater$1.run(PollingServerListUpdater.java:116) ~[ribbon-loadbalancer-2.3.0.jar!/:2.3.0]
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) [na:1.8.0_191]
at java.util.concurrent.FutureTask.runAndReset(FutureTask.java:308) [na:1.8.0_191]
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$301(ScheduledThreadPoolExecutor.java:180) [na:1.8.0_191]
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:294) [na:1.8.0_191]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) [na:1.8.0_191]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) [na:1.8.0_191]
at java.lang.Thread.run(Thread.java:748) [na:1.8.0_191]
處理方法是創建ServiceAccount對象，步驟如下：
- 創建名爲fabric8-rbac.yaml的文件，內容如下：
# NOTE: The service account `default:default` already exists in k8s cluster.
# You can create a new account following like this:
#---
#apiVersion: v1
#kind: ServiceAccount
#metadata:
# name: <new-account-name>
# namespace: <namespace>
---
apiVersion: rbac.authorization.k8s.io/v1beta1
kind: ClusterRoleBinding
metadata:
name: fabric8-rbac
subjects:
- kind: ServiceAccount
# Reference to upper's `metadata.name`
name: default
# Reference to upper's `metadata.namespace`
namespace: default
roleRef:
kind: ClusterRole
name: cluster-admin
apiGroup: rbac.authorization.k8s.io
- 執行以下命令即可創建ServiceAccount對象：
kubectl apply -f fabric8-rbac.yaml
- 再在瀏覽器上繼續剛纔的驗證，可以操作成功；
最後一個疑問
再回顧一下k8sgatewaydemo的開發過程，您會發現除了依賴spring-cloud-kubernetes對應的maven庫，我們並沒有顯式調用spring-cloud-kubernetes相關的API或者做相關配置，就獲取了所在kubernetes環境的原生服務，這是怎麼回事呢？爲何成本如此的低？ 答案就在《spring-cloud-kubernetes背後的三個關鍵知識點》一文中，推薦您回顧一下此文。
至此，spring-cloud-kubernetes框架下的SpringCloud Gateway開發實戰就完成了，希望本文能幫助您更好的理解和使用spring-cloud-kubernetes，更加高效的將應用向容器化遷移。