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本文是《spring-cloud-kubernetes 实战系列》的第四篇,主要内容是在 kubernetes 上部署两个应用:Web-Service 和 Account-Service,通过 spring-cloud-kubernetes 提供的注册发现能力,实现 Web-Service 调用 Account-Service 提供的 http 服务;
全文概览
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本文由以下段落组成:
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环境信息
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常见的 SpringCloud 注册发现服务一览
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分析 kubernetes 上如何实现服务注册发现
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本章实战源码下载链接
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实战开发 Account-Service 服务(服务提供方)
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实战开发 Web-Service 服务(服务消费方)
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扩容验证 ribbon 轮询能力
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验证熔断能力
环境信息
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本次实战的环境和版本信息如下:
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操作系统:CentOS Linux release 7.6.1810
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minikube:1.1.1
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Java:1.8.0_191
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Maven:3.6.0
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fabric8-maven-plugin 插件:3.5.37
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spring-cloud-kubernetes:1.0.1.RELEASE
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上面的 linux、minikube、java、maven,请确保已准备好,linux 环境下 minikube 的安装和启动请参考《Linux 安装 minikube 指南 》。
常见的 SpringCloud 注册发现服务一览
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SpringCloud 环境最重要的功能是注册发现服务,因此将 SpringCloud 应用迁移到 kubernetes 环境时,开发者最关心的问题是在 kubernetes 上如何将自身服务暴露出去,以及如何调用其他微服务。
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先看看普通 SpringCloud 环境下的注册发现,下图来自 spring 官方博客,地址是:https://spring.io/blog/2015/07/14/microservices-with-spring,
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由上图可见,应用 Account-Service 将自己注册到 Eureka,这样 Web-Service 用"account-service"就能在 Eureka 找到 Account-Service 服务的地址,然后顺利发送 RestFul 请求到 Account-Service,用上其提供的服务。
分析 kubernetes 上如何实现服务注册发现
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如果将上面的 Web-Service 和 Account-Service 两个应用迁移到 kubernetes 上之后,注册发现机制变成了啥样呢?
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第一种:沿用上图的方式,将 Eureka 也部署在 kubernetes 上,这样的架构和不用 kubernetes 时没有啥区别;
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第二种,就是今天要实战的内容,使用 spring-cloud-kubernetes 框架,该框架可以调用 kubernetes 的原生能力来为现有 SpringCloud 应用提供服务,架构如下图所示:
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上图表明,Web-Service 应用在调用 Account-Service 应用的服务时,会用 okhttp 向 API Server 请求服务列表,API Server 收到请求后会去 etcd 取数据返回给 Web-Service 应用,这样 Web-Service 就有了 Account-Service 的信息,可以向 Account-Service 的多个 Pod 轮询发起请求;
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上图有个细节请注意:WebService 应用并不是直接将请求发送给 Account-Service 在 kubernetes 创建的 service,而是直接发送到具体的 Pod 上了,之所以具有这个能力,是因为 spring-cloud-kubernetes 框架通过 service 拿到了 Account-Service 对应的所有 Pod 信息(endpoint),此逻辑可以参考源码 KubernetesServerList.java,如下所示:
public List<Server> getUpdatedListOfServers() {
//用namespace和serviceId做条件,得到该服务对应的所有节点(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 + "]");
}
//遍历所有的endpoint,取出IP地址和端口,构建成Server实例,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;
}
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理论分析已经完成,接下来就开始实战吧
源码下载
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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:
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这个 git 项目中有多个文件夹,本章的 Account-Service 源码在 spring-cloud-k8s-account-service 文件夹下,Web-Service 源码在 spring-cloud-k8s-web-service 文件夹下,如下图红框所示:
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下面是详细的编码过程;
开发和部署 Account-Service 服务
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Account-Service 服务是个很普通的 springboot 应用,和 spring-cloud-kubernetes 没有任何关系:
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通过 maven 创建一个 springboot 应用,artifactId 是 account-service ,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>2.1.1.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>
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由上面的 pom.xml 内容可见,account-service 应用是个简单的 web 应用,和 SpringCloud、spring-cloud-kubernetes 都没有任何关系,和其他 springboot 唯一的不同就是用到了 fabric8-maven-plugin 插件,可以方便的将应用部署到 kubernetes 环境;
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application.yml 内容如下,依旧很简单:
spring:
application:
name: account-service
server:
port: 8080
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对外提供服务的是 AccountController ,方法 getName 返回了当前容器的 hostname,方法 health 用于响应 kubernetes 的两个探针,方法 ribbonPing 用于响应使用了 ribbon 服务的调用方,它们会调用这个接口来确定当前服务是否正常:
@RestController
public class AccountController {
private static final Logger LOG = LoggerFactory.getLogger(AccountController.class);
private final String hostName = System.getenv("HOSTNAME");
/**
* 探针检查响应类
* @return
*/
@RequestMapping("/health")
public String health() {
return "OK";
}
@RequestMapping("/")
public String ribbonPing(){
LOG.info("ribbonPing of {}", hostName);
return hostName;
}
/**
* 返回hostname
* @return 当前应用所在容器的hostname.
*/
@RequestMapping("/name")
public String getName() {
return this.hostName
+ ", "
+ new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(new Date());
}
}
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将上述工程的源码放在 minikube 机器上,确保 maven 设置正常,然后在 pom.xml 文件所在目录执行以下命令,即可编译构建工程并部署到 kubernetes 上:
mvn clean install fabric8:deploy -Dfabric8.generator.from=fabric8/java-jboss-openjdk8-jdk -Pkubernetes
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执行成功后控制台输出如下:
...
[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] ------------------------------------------------------------------------
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检查 kubernetes 上的部署和服务是否正常:
[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
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minikube 的 service 命令可以得到指定服务的访问地址:
[root@minikube spring-cloud-k8s-account-service]# minikube service account-service --url
http://192.168.121.133:32596
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可见 account-service 的服务可以通过这个 url 访问:http://192.168.121.133:32596
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用浏览器访问地址:http://192.168.121.133:32596/name ,如下图所示,可以正常访问 account-service 提供的服务:
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现在 account-service 服务已经就绪,接下来是开发和部署 web-service 应用。
开发和部署 Web-Service 服务
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Web-Service 服务是个 springboot 应用,用到了 spring-cloud-kubernetes 提供的注册发现能力,以轮询的方式访问指定服务的全部 pod:
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通过 maven 创建一个 springboot 应用,artifactId 是 web-service ,pom.xml 内容如下,要重点关注的是 spring-cloud-starter-kubernetes-ribbon 的依赖:
<?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>
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application.yml 的内容如下,增加了熔断的配置:
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
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创建一个 ribbon 的配置类 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配置类
* @author: willzhao E-mail: [email protected]
* @date: 2019/6/16 11:52
*/
public class RibbonConfiguration {
@Autowired
IClientConfig ribbonClientConfig;
/**
* 检查服务是否可用的实例,
* 此地址返回的响应的返回码如果是200表示服务可用
* @param config
* @return
*/
@Bean
public IPing ribbonPing(IClientConfig config){
return new PingUrl();
}
/**
* 轮询规则
* @param config
* @return
*/
@Bean
public IRule ribbonRule(IClientConfig config){
return new AvailabilityFilteringRule();
}
}
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应用启动类如下,注意增加了服务发现、熔断、ribbon 的配置,还定义了 restTemplte 实例,注意 @LoadBalanced 注解:
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();
}
}
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远程调用 account-service 的 http 接口的逻辑被放进服务类 AccountService 中,注意 URL 中用的是服务名 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: 这里面封装了远程调用account-service提供服务的逻辑
* @author: willzhao E-mail: [email protected]
* @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);
}
/**
* 熔断时调用的方法
* @return
*/
private String getFallbackName() {
return "Fallback"
+ ", "
+ new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(new Date());
}
}
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最后是响应 web 请求的 WebServiceController 类,这里面调用了 AccountService 的服务,这样我们从 web 发起请求后,web-service 就会远程调用 account-service 的服务:
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: 测试用的controller,会远程调用account-service的服务
* @author: willzhao E-mail: [email protected]
* @date: 2019/6/16 11:46
*/
@RestController
public class WebServiceController {
@Autowired
private AccountService accountService;
/**
* 探针检查响应类
* @return
*/
@RequestMapping("/health")
public String health() {
return "OK";
}
/**
* 远程调用account-service提供的服务
* @return 多次远程调返回的所有结果.
*/
@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();
}
}
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将上述工程的源码放在 minikube 机器上,确保 maven 设置正常,然后在 pom.xml 文件所在目录执行以下命令,即可编译构建工程并部署到 kubernetes 上:
mvn clean install fabric8:deploy -Dfabric8.generator.from=fabric8/java-jboss-openjdk8-jdk -Pkubernetes
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执行成功后控制台输出如下:
...
[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] ------------------------------------------------------------------------
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检查 kubernetes 上的部署和服务是否正常:
[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
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minikube 的 service 命令可以得到指定服务的访问地址:
[root@minikube spring-cloud-k8s-web-service]# minikube service web-service --url
http://192.168.121.133:30519
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可见 web-service 的服务可以通过这个 url 访问:http://192.168.121.133:30519
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用浏览器访问地址:http://192.168.121.133:30519/account ,如下图所示,页面上展示的内容都是 web-service 调用了 account-service 的接口返回的,证明 kubernetes 上的注册发现能力正常:
扩容验证 ribbon 轮询能力
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虽然 web-service 可以正常调用 account-service 的服务,但始终访问的是一个 pod,接下来我们就对 account-service 的 pod 进行扩容,将数量调整为 2 个,看看 web-service 是否可以轮询调用每个 account-service 的 pod:
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执行以下命令即可将 pod 数量调整为 2 个:
kubectl scale --replicas=2 deployment account-service
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2. 检查 account-service 的 pod,发现已经有两个了(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
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用浏览器访问地址:http://192.168.121.133:30519/account ,如下图所示,account-sercice 返回的 hostname 已经变成了两种,和前面查到的 pod 的 name 一致,可见 web-service 的确是通过 ribbon 轮询访问了多个 account-service 的 pod:
验证熔断能力
接下来验证 web-service 配置的熔断服务是否可以生效:
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执行以下命令将 account-service 的 deployment 删除:
kubectl delete deployment account-service
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再浏览器访问地址:http://192.168.121.133:30519/account ,如下图所示,页面上的"Fallback"是配置的熔断方法返回的内容,可见熔断配置已经生效:
3. 再回到 web-service 的 pom.xml 所在位置执行以下命令,这样会重新构建部署一次 web-service 服务:
mvn clean install fabric8:deploy -Dfabric8.generator.from=fabric8/java-jboss-openjdk8-jdk -Pkubernetes
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再浏览器访问地址:http://192.168.121.133:30519/account ,如下图所示,服务成功恢复:
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至此,spring-cloud-kubernetes 的服务发现和轮询实战(含熔断)就全部完成了,利用 API Server 提供的信息,spring-cloud-kubernetes 将原生的 kubernetes 服务带给了 SpringCloud 应用,帮助传统微服务更好的融合在 kubernetes 环境中,如果您也在考虑将应用迁移到 kubernetes 上,希望本文能给您一些参考。