spring-cloud-kubernetes的服務發現和輪詢實戰(含熔斷)
本文是《spring-cloud-kubernetes實戰系列》的第四篇，主要內容是在kubernetes上部署兩個應用：Web-Service和Account-Service，經過spring-cloud-kubernetes提供的註冊發現能力，實現Web-Service調用Account-Service提供的http服務；java
系列文章列表
- 《spring-cloud-kubernetes官方demo運行實戰》
- 《你好spring-cloud-kubernetes》
- 《spring-cloud-kubernetes背後的三個關鍵知識點》
- 《spring-cloud-kubernetes的服務發現和輪詢實戰(含熔斷)》
- 《spring-cloud-kubernetes與SpringCloud Gateway》
- 《spring-cloud-kubernetes與k8s的configmap》
全文概覽
本文由如下段落組成：linux
- 環境信息
- 常見的SpringCloud註冊發現服務一覽
- 分析kubernetes上如何實現服務註冊發現
- 本章實戰源碼下載連接
- 實戰開發Account-Service服務(服務提供方)
- 實戰開發Web-Service服務(服務消費方)
- 擴容驗證ribbon輪詢能力
- 驗證熔斷能力
環境信息
本次實戰的環境和版本信息以下：git
- 操做系統：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
上面的linux、minikube、java、maven，請確保已準備好，linux環境下minikube的安裝和啓動請參考《Linux安裝minikube指南 》。程序員
常見的SpringCloud註冊發現服務一覽
SpringCloud環境最重要的功能是註冊發現服務，所以將SpringCloud應用遷移到kubernetes環境時，開發者最關心的問題是在kubernetes上如何將自身服務暴露出去，以及如何調用其餘微服務。github
先看看普通SpringCloud環境下的註冊發現，下圖來自spring官方博客，地址是：https://spring.io/blog/2015/07/14/microservices-with-spring，
web
由上圖可見，應用Account-Service將本身註冊到Eureka，這樣Web-Service用"account-service"就能在Eureka找到Account-Service服務的地址，而後順利發送RestFul請求到Account-Service，用上其提供的服務。spring
分析kubernetes上如何實現服務註冊發現
若是將上面的Web-Service和Account-Service兩個應用遷移到kubernetes上以後，註冊發現機制變成了啥樣呢？
第一種：沿用上圖的方式，將Eureka也部署在kubernetes上，這樣的架構和不用kubernetes時沒有啥區別；
第二種，就是今天要實戰的內容，使用spring-cloud-kubernetes框架，該框架能夠調用kubernetes的原生能力來爲現有SpringCloud應用提供服務，架構以下圖所示：
上圖代表，Web-Service應用在調用Account-Service應用的服務時，會用okhttp向API Server請求服務列表，API Server收到請求後會去etcd取數據返回給Web-Service應用，這樣Web-Service就有了Account-Service的信息，能夠向Account-Service的多個Pod輪詢發起請求；shell
上圖有個細節請注意：WebService應用並非直接將請求發送給Account-Service在kubernetes建立的service，而是直接發送到具體的Pod上了，之因此具備這個能力，是由於spring-cloud-kubernetes框架經過service拿到了Account-Service對應的全部Pod信息（endpoint），此邏輯能夠參考源碼KubernetesServerList.java，以下所示：apache
public List<Server> getUpdatedListOfServers() {
//用namespace和serviceId作條件，獲得該服務對應的全部節點(endpoints)信息
Endpoints endpoints = this.namespace != null
? this.client.endpoints().inNamespace(this.namespace)
.withName(this.serviceId).get()
: this.client.endpoints().withName(this.serviceId).get();
List<Server> result = new ArrayList<Server>();
if (endpoints != null) {
if (LOG.isDebugEnabled()) {
LOG.debug("Found [" + endpoints.getSubsets().size()
+ "] endpoints in namespace [" + this.namespace + "] for name ["
+ this.serviceId + "] and portName [" + this.portName + "]");
}
//遍歷全部的endpoint，取出IP地址和端口，構建成Server實例，放入result集合中
for (EndpointSubset subset : endpoints.getSubsets()) {
if (subset.getPorts().size() == 1) {
EndpointPort port = subset.getPorts().get(FIRST);
for (EndpointAddress address : subset.getAddresses()) {
result.add(new Server(address.getIp(), port.getPort()));
}
}
else {
for (EndpointPort port : subset.getPorts()) {
if (Utils.isNullOrEmpty(this.portName)
|| this.portName.endsWith(port.getName())) {
for (EndpointAddress address : subset.getAddresses()) {
result.add(new Server(address.getIp(), port.getPort()));
}
}
}
}
}
}
else {
LOG.warn("Did not find any endpoints in ribbon in namespace ["
+ this.namespace + "] for name [" + this.serviceId
+ "] and portName [" + this.portName + "]");
}
return result;
}
理論分析已經完成，接下來就開始實戰吧json
源碼下載
若是您不打算寫代碼，也能夠從GitHub上下載本次實戰的源碼，地址和連接信息以下表所示：
| 名稱 | 連接 | 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) | git@github.com: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Account-Service源碼在spring-cloud-k8s-account-service文件夾下，Web-Service源碼在spring-cloud-k8s-web-service文件夾下，以下圖紅框所示：
下面是詳細的編碼過程；
開發和部署Account-Service服務
Account-Service服務是個很普通的springboot應用，和spring-cloud-kubernetes沒有任何關係：
- 經過maven建立一個springboot應用，artifactId是account-service，pom.xml內容以下：
<?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>2.1.1.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<groupId>com.bolingcavalry</groupId>
<artifactId>account-service</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>account-service</name>
<description>Demo project for Spring Cloud service provider run in kubernetes</description>
<properties>
<java.version>1.8</java.version>
<spring-boot.version>2.1.1.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.version>2.1.1.RELEASE</springcloud.version>
</properties>
<dependencyManagement>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-dependencies</artifactId>
<type>pom</type>
<scope>import</scope>
<version>${spring-boot.version}</version>
</dependency>
</dependencies>
</dependencyManagement>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter</artifactId>
<version>${springcloud.version}</version>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
<version>${springcloud.version}</version>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
<version>${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>
由上面的pom.xml內容可見，account-service應用是個簡單的web應用，和SpringCloud、spring-cloud-kubernetes都沒有任何關係，和其餘springboot惟一的不一樣就是用到了fabric8-maven-plugin插件，能夠方便的將應用部署到kubernetes環境；
- application.yml內容以下，依舊很簡單：
spring:
application:
name: account-service
server:
port: 8080
- 對外提供服務的是AccountController ，方法getName返回了當前容器的hostname，方法health用於響應kubernetes的兩個探針，方法ribbonPing用於響應使用了ribbon服務的調用方，它們會調用這個接口來肯定當前服務是否正常：
@RestController
public class AccountController {
private static final Logger LOG = LoggerFactory.getLogger(AccountController.class);
private final String hostName = System.getenv("HOSTNAME");
/**
* 探針檢查響應類
* @return
*/
@RequestMapping("/health")
public String health() {
return "OK";
}
@RequestMapping("/")
public String ribbonPing(){
LOG.info("ribbonPing of {}", hostName);
return hostName;
}
/**
* 返回hostname
* @return 當前應用所在容器的hostname.
*/
@RequestMapping("/name")
public String getName() {
return this.hostName
+ ", "
+ new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(new Date());
}
}
- 將上述工程的源碼放在minikube機器上，確保maven設置正常，而後在pom.xml文件所在目錄執行如下命令，便可編譯構建工程並部署到kubernetes上：
mvn clean install fabric8:deploy -Dfabric8.generator.from=fabric8/java-jboss-openjdk8-jdk -Pkubernetes
執行成功後控制檯輸出以下：
... [INFO] Installing /usr/local/work/k8s/ribbon/spring-cloud-k8s-account-service/target/classes/META-INF/fabric8/kubernetes.json to /root/.m2/repository/com/bolingcavalry/account-service/0.0.1-SNAPSHOT/account-service-0.0.1-SNAPSHOT-kubernetes.json [INFO] [INFO] <<< fabric8-maven-plugin:3.5.37:deploy (default-cli) < install @ account-service <<< [INFO] [INFO] [INFO] --- fabric8-maven-plugin:3.5.37:deploy (default-cli) @ account-service --- [INFO] F8: Using Kubernetes at https://192.168.121.133:8443/ in namespace default with manifest /usr/local/work/k8s/ribbon/spring-cloud-k8s-account-service/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-account-service.json [INFO] Using namespace: default [INFO] Updating Deployment from kubernetes.yml [INFO] Updated Deployment: target/fabric8/applyJson/default/deployment-account-service.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: 11.941 s [INFO] Finished at: 2019-06-16T19:00:51+08:00 [INFO] ------------------------------------------------------------------------
- 檢查kubernetes上的部署和服務是否正常：
[root@minikube spring-cloud-k8s-account-service]# kubectl get deployments NAME READY UP-TO-DATE AVAILABLE AGE account-service 1/1 1 1 69m [root@minikube spring-cloud-k8s-account-service]# kubectl get services NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE account-service NodePort 10.105.157.201 <none> 8080:32596/TCP 69m kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 8d
- minikube的service命令能夠獲得指定服務的訪問地址：
[root@minikube spring-cloud-k8s-account-service]# minikube service account-service --url http://192.168.121.133:32596
可見account-service的服務能夠經過這個url訪問：http://192.168.121.133:32596
用瀏覽器訪問地址：http://192.168.121.133:32596/name ，以下圖所示，能夠正常訪問account-service提供的服務：
如今account-service服務已經就緒，接下來是開發和部署web-service應用。開發和部署Web-Service服務
Web-Service服務是個springboot應用，用到了spring-cloud-kubernetes提供的註冊發現能力，以輪詢的方式訪問指定服務的所有pod：- 經過maven建立一個springboot應用，artifactId是web-service，pom.xml內容以下，要重點關注的是spring-cloud-starter-kubernetes-ribbon的依賴：
<?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>2.1.1.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<groupId>com.bolingcavalry</groupId>
<artifactId>web-service</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>web-service</name>
<description>Demo project for Spring Cloud service consumer run in kubernetes</description>
<properties>
<java.version>1.8</java.version>
<spring-boot.version>2.1.1.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>
<springcloud.version>2.1.1.RELEASE</springcloud.version>
</properties>
<dependencyManagement>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-dependencies</artifactId>
<type>pom</type>
<scope>import</scope>
<version>${spring-boot.version}</version>
</dependency>
</dependencies>
</dependencyManagement>
<dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-kubernetes-core</artifactId>
<version>${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>
<version>${springcloud.version}</version>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter</artifactId>
<version>${springcloud.version}</version>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
<version>${springcloud.version}</version>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-netflix-ribbon</artifactId>
<version>${springcloud.version}</version>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-netflix-hystrix</artifactId>
<version>${springcloud.version}</version>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
<version>${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>
- application.yml的內容以下，增長了熔斷的配置：
spring:
application:
name: web-service
server:
port: 8080
backend:
ribbon:
eureka:
enabled: false
client:
enabled: true
ServerListRefreshInterval: 5000
hystrix.command.BackendCall.execution.isolation.thread.timeoutInMilliseconds: 5000
hystrix.threadpool.BackendCallThread.coreSize: 5
- 建立一個ribbon的配置類RibbonConfiguration：
package com.bolingcavalry.webservice;
import com.netflix.client.config.IClientConfig;
import com.netflix.loadbalancer.AvailabilityFilteringRule;
import com.netflix.loadbalancer.IPing;
import com.netflix.loadbalancer.IRule;
import com.netflix.loadbalancer.PingUrl;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Bean;
/**
* @Description: ribbon配置類
* @author: willzhao E-mail: zq2599@gmail.com
* @date: 2019/6/16 11:52
*/
public class RibbonConfiguration {
@Autowired
IClientConfig ribbonClientConfig;
/**
* 檢查服務是否可用的實例，
* 此地址返回的響應的返回碼若是是200表示服務可用
* @param config
* @return
*/
@Bean
public IPing ribbonPing(IClientConfig config){
return new PingUrl();
}
/**
* 輪詢規則
* @param config
* @return
*/
@Bean
public IRule ribbonRule(IClientConfig config){
return new AvailabilityFilteringRule();
}
}
- 應用啓動類以下，注意增長了服務發現、熔斷、ribbon的配置，還定義了restTemplte實例，注意@LoadBalanced註解：
package com.bolingcavalry.webservice;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.circuitbreaker.EnableCircuitBreaker;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
import org.springframework.cloud.client.loadbalancer.LoadBalanced;
import org.springframework.cloud.netflix.ribbon.RibbonClient;
import org.springframework.context.annotation.Bean;
import org.springframework.web.client.RestTemplate;
@SpringBootApplication
@EnableDiscoveryClient
@EnableCircuitBreaker
@RibbonClient(name="account-service", configuration = RibbonConfiguration.class)
public class WebServiceApplication {
public static void main(String[] args) {
SpringApplication.run(WebServiceApplication.class, args);
}
@LoadBalanced
@Bean
RestTemplate restTemplate(){
return new RestTemplate();
}
}
- 遠程調用account-service的http接口的邏輯被放進服務類AccountService中，注意URL中用的是服務名account-service：
package com.bolingcavalry.webservice;
import com.netflix.hystrix.contrib.javanica.annotation.HystrixCommand;
import com.netflix.hystrix.contrib.javanica.annotation.HystrixProperty;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.web.client.RestTemplate;
import java.text.SimpleDateFormat;
import java.util.Date;
/**
* @Description: 這裏面封裝了遠程調用account-service提供服務的邏輯
* @author: willzhao E-mail: zq2599@gmail.com
* @date: 2019/6/16 12:21
*/
@Service
public class AccountService {
@Autowired
private RestTemplate restTemplate;
@HystrixCommand(fallbackMethod = "getFallbackName" ,commandProperties = {
@HystrixProperty(name = "execution.isolation.thread.timeoutInMilliseconds", value = "1000") })
public String getDataFromSpringCloudK8SProvider(){
return this.restTemplate.getForObject("http://account-service/name", String.class);
}
/**
* 熔斷時調用的方法
* @return
*/
private String getFallbackName() {
return "Fallback"
+ ", "
+ new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(new Date());
}
}
- 最後是響應web請求的WebServiceController類，這裏面調用了AccountService的服務，這樣咱們從web發起請求後，web-service就會遠程調用account-service的服務：
package com.bolingcavalry.webservice;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;
/**
* @Description: 測試用的controller，會遠程調用account-service的服務
* @author: willzhao E-mail: zq2599@gmail.com
* @date: 2019/6/16 11:46
*/
@RestController
public class WebServiceController {
@Autowired
private AccountService accountService;
/**
* 探針檢查響應類
* @return
*/
@RequestMapping("/health")
public String health() {
return "OK";
}
/**
* 遠程調用account-service提供的服務
* @return 屢次遠程調返回的全部結果.
*/
@RequestMapping("/account")
public String account() {
StringBuilder sbud = new StringBuilder();
for(int i=0;i<10;i++){
sbud.append(accountService.getDataFromSpringCloudK8SProvider())
.append("<br>");
}
return sbud.toString();
}
}
- 將上述工程的源碼放在minikube機器上，確保maven設置正常，而後在pom.xml文件所在目錄執行如下命令，便可編譯構建工程並部署到kubernetes上：
mvn clean install fabric8:deploy -Dfabric8.generator.from=fabric8/java-jboss-openjdk8-jdk -Pkubernetes
執行成功後控制檯輸出以下：
... [INFO] Installing /usr/local/work/k8s/ribbon/spring-cloud-k8s-web-service/target/classes/META-INF/fabric8/kubernetes.json to /root/.m2/repository/com/bolingcavalry/web-service/0.0.1-SNAPSHOT/web-service-0.0.1-SNAPSHOT-kubernetes.json [INFO] [INFO] <<< fabric8-maven-plugin:3.5.37:deploy (default-cli) < install @ web-service <<< [INFO] [INFO] [INFO] --- fabric8-maven-plugin:3.5.37:deploy (default-cli) @ web-service --- [INFO] F8: Using Kubernetes at https://192.168.121.133:8443/ in namespace default with manifest /usr/local/work/k8s/ribbon/spring-cloud-k8s-web-service/target/classes/META-INF/fabric8/kubernetes.yml [INFO] Using namespace: default [INFO] Creating a Service from kubernetes.yml namespace default name web-service [INFO] Created Service: target/fabric8/applyJson/default/service-web-service.json [INFO] Using namespace: default [INFO] Creating a Deployment from kubernetes.yml namespace default name web-service [INFO] Created Deployment: target/fabric8/applyJson/default/deployment-web-service.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: 12.792 s [INFO] Finished at: 2019-06-16T19:24:21+08:00 [INFO] ------------------------------------------------------------------------
- 檢查kubernetes上的部署和服務是否正常：
[root@minikube spring-cloud-k8s-web-service]# kubectl get deployments NAME READY UP-TO-DATE AVAILABLE AGE account-service 1/1 1 1 109m web-service 1/1 1 1 18m [root@minikube spring-cloud-k8s-web-service]# kubectl get svc NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE account-service NodePort 10.105.157.201 <none> 8080:32596/TCP 109m kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 8d web-service NodePort 10.99.211.179 <none> 8080:30519/TCP 18m
- minikube的service命令能夠獲得指定服務的訪問地址：
[root@minikube spring-cloud-k8s-web-service]# minikube service web-service --url http://192.168.121.133:30519
可見web-service的服務能夠經過這個url訪問：http://192.168.121.133:30519
用瀏覽器訪問地址：http://192.168.121.133:30519/account ，以下圖所示，頁面上展現的內容都是web-service調用了account-service的接口返回的，證實kubernetes上的註冊發現能力正常：
擴容驗證ribbon輪詢能力
雖然web-service能夠正常調用account-service的服務，但始終訪問的是一個pod，接下來咱們就對account-service的pod進行擴容，將數量調整爲2個，看看web-service是否能夠輪詢調用每一個account-service的pod：- 執行如下命令便可將pod數量調整爲2個：
kubectl scale --replicas=2 deployment account-service
- 檢查account-service的pod，發現已經有兩個了(account-service-5554576647-m29xr和account-service-5554576647-zwwml)：
[root@minikube spring-cloud-k8s-web-service]# kubectl get pods NAME READY STATUS RESTARTS AGE account-service-5554576647-m29xr 1/1 Running 0 53m account-service-5554576647-zwwml 1/1 Running 0 20s web-service-6d775855c7-7lkvr 1/1 Running 0 29m
用瀏覽器訪問地址：http://192.168.121.133:30519/account ，以下圖所示，account-sercice返回的hostname已經變成了兩種，和前面查到的pod的name一致，可見web-service的確是經過ribbon輪詢訪問了多個account-service的pod：
驗證熔斷能力
接下來驗證web-service配置的熔斷服務是否能夠生效：- 執行如下命令將account-service的deployment刪除：
kubectl delete deployment account-service
- 再瀏覽器訪問地址：http://192.168.121.133:30519/account ，以下圖所示，頁面上的"Fallback"是配置的熔斷方法返回的內容，可見熔斷配置已經生效：
- 再回到web-service的pom.xml所在位置執行如下命令，這樣會從新構建部署一次web-service服務：
mvn clean install fabric8:deploy -Dfabric8.generator.from=fabric8/java-jboss-openjdk8-jdk -Pkubernetes
- 再瀏覽器訪問地址：http://192.168.121.133:30519/account ，以下圖所示，服務成功恢復：
至此，spring-cloud-kubernetes的服務發現和輪詢實戰(含熔斷)就所有完成了，利用API Server提供的信息，spring-cloud-kubernetes將原生的kubernetes服務帶給了SpringCloud應用，幫助傳統微服務更好的融合在kubernetes環境中，若是您也在考慮將應用遷移到kubernetes上，但願本文能給您一些參考。
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