spring-cloud-kubernetes与SpringCloud Gateway
repackagetruetruefalseio.fabric8fmpresourcekubernetesio.fabric8fmpresourcebuildNodePort部署完成后终端输出类似如下成功信息：[INFO][INFO][INFO]即可访问到webdemo应用；
org.springframework.boot
spring-boot-maven-plugin
${spring-boot.version}
repackage
org.apache.maven.plugins
maven-deploy-plugin
${maven-deploy-plugin.version}
true
org.apache.maven.plugins
maven-surefire-plugin
${maven-surefire-plugin.version}
true
false
io.fabric8
fabric8-maven-plugin
${fabric8.maven.plugin.version}
fmp
resource
kubernetes
io.fabric8
fabric8-maven-plugin
${fabric8.maven.plugin.version}
fmp
resource
build
NodePort
- 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] ------------------------------------------------------------------------
- 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 10.96.0.1 443/TCP 29d
webdemo NodePort 10.106.98.137 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服务对外暴露的地址：
[root@minikube webdemo]# minikube service webdemo --url
http://192.168.121.133:30160
可见外部通过地址：http://192.168.121.133:30160 即可访问到webdemo应用；
7. 在浏览器输入地址：http://192.168.121.133:30160/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：
至此，webdemo在minikue上已经正常运行，该开发gateway应用了；
开发k8sgatewaydemo
- 基于maven创建一个名为k8sgatewaydemo的springboot应用，pom.xml内容如下：
<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”>
4.0.0
org.springframework.boot
spring-boot-starter-parent
2.1.6.RELEASE
com.bolingcavalry
k8sgatewaydemo
0.0.1-SNAPSHOT
k8sgatewaydemo
Demo project for Spring Boot
<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>
org.springframework.cloud
spring-cloud-starter-gateway
org.springframework.boot
spring-boot-starter-test
test
org.springframework.cloud
spring-cloud-kubernetes-core
${springcloud.kubernetes.version}
org.springframework.cloud
spring-cloud-kubernetes-discovery
${springcloud.kubernetes.version}
org.springframework.cloud
spring-cloud-starter-kubernetes-ribbon
${springcloud.kubernetes.version}
org.springframework.cloud
spring-cloud-commons
org.springframework.boot
spring-boot-starter
org.springframework.cloud
spring-cloud-starter-netflix-ribbon
org.springframework.cloud
spring-cloud-starter-netflix-hystrix
org.springframework.cloud
spring-cloud-dependencies
${spring-cloud.version}
pom
import
org.springframework.boot
spring-boot-maven-plugin
${spring-boot.version}
repackage
org.apache.maven.plugins
maven-deploy-plugin
${maven-deploy-plugin.version}
true
org.apache.maven.plugins
maven-surefire-plugin
${maven-surefire-plugin.version}
true
false
io.fabric8
fabric8-maven-plugin
${fabric8.maven.plugin.version}
fmp
resource
kubernetes
io.fabric8
fabric8-maven-plugin
${fabric8.maven.plugin.version}
fmp
resource
build
NodePort
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: {}
- 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；
3. 配置文件application.yml的内容：
spring:
application:
name: gateway
cloud:
gateway:
discovery:
locator:
enabled: true
lowerCaseServiceId: true
- 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] ------------------------------------------------------------------------
- 查看service和pod，确认一切正常：
[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 8080:31352/TCP 129m
kubernetes ClusterIP 10.96.0.1 443/TCP 29d
webdemo NodePort 10.106.98.137 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服务对外暴露的地址：
[root@minikube k8sgatewaydemo]# minikube service k8sgatewaydemo --url
http://192.168.121.133:31352
可见外部通过地址：http://192.168.121.133:31352 即可访问到k8sgatewaydemo应用；
7. 在浏览器输入地址：http://192.168.121.133:31352/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：
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]
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