spring-cloud-kubernetes与SpringCloud Gateway

【本文转自程序员欣宸博客,将minikube改为kubernetes】

什么是SpringCloud Gateway

SpringCloud Gateway是SpringCloud技术栈下的网关服务框架,在基于SpringCloud的微服务环境中,外部请求会到达SpringCloud Gateway应用,该应用对请求做转发、过滤、鉴权、熔断等前置操作,一个典型的请求响应流程如下所示: img

SpringCloud Gateway实战参考

如果您之前没有使用过SpringCloud Gateway,推荐您阅读《速体验SpringCloud Gateway》,有时间的话动手实战效果更佳,只需编写少量代码就能快速熟悉这个SpringCloud技术栈中非常重要的功能;

kubernetes上的SpringCloud Gateway

注意以下两个知识点:

  1. SpringCloud Gateway之所以能将外部请求路由到正确的后台服务上,是因为注册中心的存在,SpringCloud Gateway可以在注册中心取得所有服务的信息,因此它可以根据路径和服务的对应关系,将请求转发到对应的服务上;
  2. 如果您看过本系列的上一篇 《spring-cloud-kubernetes的服务发现和轮询实战(含熔断)》,您就知道spring-cloud-kubernetes框架可以获取kubernetes环境内的所有服务(这里说的服务就是kubernetes的service);

将以上两个知识点结合起来,于是可以推测:运行在kubernetes环境的SpringCloud Gateway应用,如果使用了spring-cloud-kubernetes框架就能得到kubernetes的service列表,因此可以承担网关的角色,将外部请求转发至kubernetes内的service上,最终到达对应的Pod;

架构如下图所示,请注意黄色背景的对话框,里面标识了关键操作: img 至此,理论分析已经完成,我们来实战验证这个理论,接下来我们开发两个java应用:

  1. 先开发一个普通的web服务,名为webdemo,提供一个http接口;
  2. 再开发一个SpringCloud Gateway应用,名为k8sgatewaydemo;

环境信息

本次实战的环境和版本信息如下:

  • 操作系统:Ubuntu 18.04.4
  • Kubernetes:1.15.2
  • 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

源码下载

如果您不打算写代码,也可以从GitHub上下载本次实战的源码,地址和链接信息如下表所示:

名称 链接 备注
项目主页 https://github.com/zq2599/blog_demos 该项目在GitHub上的主页
git仓库地址(https) https://github.com/zq2599/blog_demos.git 该项目源码的仓库地址,https协议
git仓库地址(ssh) git@github.com:zq2599/blog_demos.git 该项目源码的仓库地址,ssh协议

这个git项目中有多个文件夹,本章的两个应用分别在webdemo和k8sgatewaydemo文件夹下; 下图红框中是webdemo应用的源码: img 下图红框中是k8sgatewaydemo应用的源码: img 下面是详细的编码过程;

开发webdemo

webdemo是个极其普通的spring boot应用,和SpringCloud没有任何关系;

  1. webdemo提供一个http接口,将请求header中名为extendtag的参数返回给请求方,controller类如下:

    @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")
                + "]";
    }
    }
  2. 启动类WebdemoApplication.java:

    @SpringBootApplication
    public class WebdemoApplication {
    public static void main(String[] args) {
        SpringApplication.run(WebdemoApplication.class, args);
    }
    }
  3. 要注意的是pom.xml,里面通过名为fabric8-maven-plugin的maven插件,将webdemo快速部署到minikube环境:

    <?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>
  4. 以上就是webdemo应用的内容了,接下来要编译、构建、部署到minikube环境,在pom.xml执行以下命令即可:

    mvn clean install fabric8:deploy -Dfabric8.generator.from=fabric8/java-jboss-openjdk8-jdk -Pkubernetes

部署完成后终端输出类似如下成功信息:

[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] ------------------------------------------------------------------------
  1. 查看service和pod,确认一切正常:

    [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
  2. 取得webdemo服务对外暴露的地址:

    kubectl get all

image-20200228104424141

  1. 可见内部通过地址:http://10.102.220.5:8080 ,外部访问地址:http://111.229.108.104:31777 即可访问到webdemo应用;

在浏览器输入地址:http://111.229.108.104:31777/hello/time ,即可验证webdemo的http接口是否正常,如下图,由于header中没有extendtag属性,因此返回的extendtag为null:

image-20200228104850072

至此,webdemo在minikue上已经正常运行,该开发gateway应用了;

开发k8sgatewaydemo

  1. 基于maven创建一个名为k8sgatewaydemo的springboot应用,pom.xml内容如下:

    <?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文件中有以下几点需要注意:

第一、 依赖spring-cloud-kubernetes-core和spring-cloud-kubernetes-discovery,这样能用到spring-cloud-kubernetes提供的服务发现能力;

第二、依赖spring-cloud-starter-gateway,这样能用上SpringCloud的gateway能力;

第三、不要依赖spring-boot-starter-web,会和spring-cloud-starter-gateway冲突,启动时抛出以下异常:

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: {}
  1. 开发SpringCloud Gateway的启动类K8sgatewaydemoApplication.java,里面也包含了网关路由配置的实例化,除了配置路径和转发服务的关系,还在请求的header中添加了extendtag属性,请注意注释的内容:

    @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()
                //增加一个path匹配,以"/customize/hello/"开头的请求都在此路由
                .route(r -> r.path("/customize/hello/**")
                        //表示将路径中的第一级参数删除,用剩下的路径与webdemo的路径做拼接,
                        //这里就是"lb://webdemo/hello/",能匹配到webdemo的HelloController的路径
                        .filters(f -> f.stripPrefix(1)
                                //在请求的header中添加一个key&value
                                .addRequestHeader("extendtag", "geteway-" + System.currentTimeMillis()))
                        //指定匹配服务webdemo,lb是load balance的意思
                        .uri("lb://webdemo")
                ).build();
    }
    }

从上述代码可见,K8sgatewaydemoApplication与普通环境下的SpringCloud Gateway并无差别,都是通过EnableDiscoveryClient注解获取服务列表,配置RouteLocator实现路由逻辑;

  1. 配置文件application.yml的内容:

    spring:
    application:
    name: gateway
    cloud:
    gateway:
      discovery:
        locator:
          enabled: true
          lowerCaseServiceId: true
  2. 以上就是k8sgatewaydemo应用的内容了,接下来要编译、构建、部署到minikube环境,在pom.xml执行以下命令即可:

    mvn clean install fabric8:deploy -Dfabric8.generator.from=fabric8/java-jboss-openjdk8-jdk -Pkubernetes

部署完成后终端输出类似如下成功信息:

[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] ------------------------------------------------------------------------
  1. 查看service和pod,确认一切正常:

    ➜  ~ kubectl get all                                        

image-20200228104424141

  1. gateway服务对外暴露的地址:

内部通过地址:http://10.99.106.180:8080 ,外部访问地址:http://111.229.108.104:31290 即可访问到webdemo应用;

在浏览器输入地址:http://111.229.108.104:31290/customize/hello/time ,即可验证k8sgatewaydemo作为网关应用,能否将路径中带有customize的请求转发到webdemo应用,并且在请求header中添加名为entendtag的属性,如下图,浏览器展示的内容是webdemo的http接口返回的,并且extendtag的内容也不为空了,而是k8sgatewaydemo在转发前写入的: image-20200228105443686

上述结果表明已可以证明我们之前的推测是正确的:SpringCloud Gateway应用在使用了spring-cloud-kubernetes提供的注册发现能力后,可以将请求转发到kubernetes环境中的服务上; 也就是说,借助spring-cloud-kubernetes框架,你在SpringCloud环境开发的SpringCloud Gateway应用,可以以很小的代价迁移到kubernetes环境,与kubernetes环境中的service可以很好的交互,而原有的eureka注册中心也可以不用了;

解决权限问题

如果您的spring-cloud-kubernetes在向webdemo转发请求时抛出以下错误,那是因为遇到了kubernetes的权限问题:

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]

处理方法是创建ServiceAccount对象,步骤如下:

  1. 创建名为fabric8-rbac.yaml的文件,内容如下:

    # 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
  2. 执行以下命令即可创建ServiceAccount对象:

    kubectl apply -f fabric8-rbac.yaml
  3. 再在浏览器上继续刚才的验证,可以操作成功;

最后一个疑问

再回顾一下k8sgatewaydemo的开发过程,您会发现除了依赖spring-cloud-kubernetes对应的maven库,我们并没有显式调用spring-cloud-kubernetes相关的API或者做相关配置,就获取了所在kubernetes环境的原生服务,这是怎么回事呢?为何成本如此的低? 答案就在《spring-cloud-kubernetes背后的三个关键知识点》一文中,推荐您回顾一下此文。

至此,spring-cloud-kubernetes框架下的SpringCloud Gateway开发实战就完成了,希望本文能帮助您更好的理解和使用spring-cloud-kubernetes,更加高效的将应用向容器化迁移。

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