用丝带的春天云彩不忽略下来服务器

时间：2017-03-14 11:34:43

标签： spring-boot load-balancing spring-cloud spring-cloud-netflix

我是eureka客户端负载均衡的关注指南：

https://spring.io/guides/gs/client-side-load-balancing/

但是当我有3个服务器实例后我关闭其中任何一个时，我得到了连接拒绝异常。客户端仍在尝试向这些服务器发送请求，而不是忽略ping失败的服务器。当客户端尝试向这些服务器发送请求时，我会在这些服务器被ping时遇到异常并且出现相同的异常。似乎功能区正在通过配置中列出的所有服务器执行某种盲目的循环，它忽略了我关闭的服务器。

application.yml 

spring:
  application:
    name: user

server:
  port: 8888

say-hello:
  ribbon:
    eureka:
      enabled: false
    listOfServers: localhost:8090,localhost:9092,localhost:9999
    ServerListRefreshInterval: 15000

SayHelloConfiguration.java 

package hello;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Bean;

import com.netflix.client.config.IClientConfig;
import com.netflix.loadbalancer.IPing;
import com.netflix.loadbalancer.IRule;
import com.netflix.loadbalancer.PingUrl;
import com.netflix.loadbalancer.AvailabilityFilteringRule;

public class SayHelloConfiguration {

    @Autowired
    IClientConfig ribbonClientConfig;

    @Bean
    public IPing ribbonPing(IClientConfig config) {
        return new PingUrl();
    }

    @Bean
    public IRule ribbonRule(IClientConfig config) {
        return new AvailabilityFilteringRule();
    }

}

UserApplication.java 

package hello;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Bean;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;
import org.springframework.cloud.client.loadbalancer.LoadBalanced;
import org.springframework.cloud.netflix.ribbon.RibbonClient;

@SpringBootApplication
@RestController
@RibbonClient(name = "say-hello", configuration = SayHelloConfiguration.class)
public class UserApplication {

    @LoadBalanced
    @Bean
    RestTemplate restTemplate(){
        return new RestTemplate();
    }

    @Autowired
    RestTemplate restTemplate;

    @RequestMapping("/hi")
    public String hi(@RequestParam(value="name", defaultValue="Artaban") String name) {
        String greeting = this.restTemplate.getForObject("http://say-hello/greeting", String.class);
        return String.format("%s, %s!", greeting, name);
    }

    public static void main(String[] args) {
        SpringApplication.run(UserApplication.class, args);
    }
}

的pom.xml 

<?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>

    <groupId>hello</groupId>
    <artifactId>user</artifactId>
    <version>1.0-SNAPSHOT</version>
    <packaging>jar</packaging>

    <name>user</name>
    <description>Demo project for Spring Boot</description>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.2.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-ribbon</artifactId>
        </dependency>
        <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>

    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>Camden.SR5</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

    <repositories>
        <repository>
            <id>spring-snapshots</id>
            <name>Spring Snapshots</name>
            <url>https://repo.spring.io/snapshot</url>
            <snapshots>
                <enabled>true</enabled>
            </snapshots>
        </repository>
        <repository>
            <id>spring-milestones</id>
            <name>Spring Milestones</name>
            <url>https://repo.spring.io/milestone</url>
            <snapshots>
                <enabled>false</enabled>
            </snapshots>
        </repository>
    </repositories>

</project>

这是我在ping服务器时遇到的例外情况：

java.net.ConnectException: Connection refused: connect
    at java.net.DualStackPlainSocketImpl.connect0(Native Method)
    at java.net.DualStackPlainSocketImpl.socketConnect(DualStackPlainSocketImpl.java:79)
    at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:350)
    at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:206)
    at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:188)
    at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:172)
    at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392)
    at java.net.Socket.connect(Socket.java:589)
    at org.apache.http.conn.scheme.PlainSocketFactory.connectSocket(PlainSocketFactory.java:121)
    at org.apache.http.impl.conn.DefaultClientConnectionOperator.openConnection(DefaultClientConnectionOperator.java:180)
    at org.apache.http.impl.conn.ManagedClientConnectionImpl.open(ManagedClientConnectionImpl.java:326)
    at org.apache.http.impl.client.DefaultRequestDirector.tryConnect(DefaultRequestDirector.java:610)
    at org.apache.http.impl.client.DefaultRequestDirector.execute(DefaultRequestDirector.java:445)
    at org.apache.http.impl.client.AbstractHttpClient.doExecute(AbstractHttpClient.java:835)
    at org.apache.http.impl.client.CloseableHttpClient.execute(CloseableHttpClient.java:83)
    at org.apache.http.impl.client.CloseableHttpClient.execute(CloseableHttpClient.java:108)
    at org.apache.http.impl.client.CloseableHttpClient.execute(CloseableHttpClient.java:56)
    at com.netflix.loadbalancer.PingUrl.isAlive(PingUrl.java:126)
    at com.netflix.loadbalancer.BaseLoadBalancer$SerialPingStrategy.pingServers(BaseLoadBalancer.java:927)
    at com.netflix.loadbalancer.BaseLoadBalancer$Pinger.runPinger(BaseLoadBalancer.java:676)
    at com.netflix.loadbalancer.BaseLoadBalancer$PingTask.run(BaseLoadBalancer.java:629)
    at java.util.TimerThread.mainLoop(Timer.java:555)
    at java.util.TimerThread.run(Timer.java:505)

这是我在客户端应用程序向下行服务器发送请求时获得的异常：

java.net.ConnectException: Connection refused: connect
    at java.net.DualStackPlainSocketImpl.connect0(Native Method) ~[na:1.8.0_101]
    at java.net.DualStackPlainSocketImpl.socketConnect(DualStackPlainSocketImpl.java:79) ~[na:1.8.0_101]
    at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:350) ~[na:1.8.0_101]
    at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:206) ~[na:1.8.0_101]
    at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:188) ~[na:1.8.0_101]
    at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:172) ~[na:1.8.0_101]
    at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392) ~[na:1.8.0_101]
    at java.net.Socket.connect(Socket.java:589) ~[na:1.8.0_101]
    at java.net.Socket.connect(Socket.java:538) ~[na:1.8.0_101]
    at sun.net.NetworkClient.doConnect(NetworkClient.java:180) ~[na:1.8.0_101]
    at sun.net.www.http.HttpClient.openServer(HttpClient.java:432) ~[na:1.8.0_101]
    at sun.net.www.http.HttpClient.openServer(HttpClient.java:527) ~[na:1.8.0_101]
    at sun.net.www.http.HttpClient.<init>(HttpClient.java:211) ~[na:1.8.0_101]
    at sun.net.www.http.HttpClient.New(HttpClient.java:308) ~[na:1.8.0_101]
    at sun.net.www.http.HttpClient.New(HttpClient.java:326) ~[na:1.8.0_101]
    at sun.net.www.protocol.http.HttpURLConnection.getNewHttpClient(HttpURLConnection.java:1169) ~[na:1.8.0_101]
    at sun.net.www.protocol.http.HttpURLConnection.plainConnect0(HttpURLConnection.java:1105) ~[na:1.8.0_101]
    at sun.net.www.protocol.http.HttpURLConnection.plainConnect(HttpURLConnection.java:999) ~[na:1.8.0_101]
    at sun.net.www.protocol.http.HttpURLConnection.connect(HttpURLConnection.java:933) ~[na:1.8.0_101]
    at org.springframework.http.client.SimpleBufferingClientHttpRequest.executeInternal(SimpleBufferingClientHttpRequest.java:78) ~[spring-web-4.3.7.RELEASE.jar:4.3.7.RELEASE]
    at org.springframework.http.client.AbstractBufferingClientHttpRequest.executeInternal(AbstractBufferingClientHttpRequest.java:48) ~[spring-web-4.3.7.RELEASE.jar:4.3.7.RELEASE]
    at org.springframework.http.client.AbstractClientHttpRequest.execute(AbstractClientHttpRequest.java:53) ~[spring-web-4.3.7.RELEASE.jar:4.3.7.RELEASE]
    at org.springframework.http.client.InterceptingClientHttpRequest$InterceptingRequestExecution.execute(InterceptingClientHttpRequest.java:99) ~[spring-web-4.3.7.RELEASE.jar:4.3.7.RELEASE]
    at org.springframework.cloud.client.loadbalancer.LoadBalancerRequestFactory$1.apply(LoadBalancerRequestFactory.java:63) ~[spring-cloud-commons-1.1.7.RELEASE.jar:1.1.7.RELEASE]
    at org.springframework.cloud.client.loadbalancer.LoadBalancerRequestFactory$1.apply(LoadBalancerRequestFactory.java:52) ~[spring-cloud-commons-1.1.7.RELEASE.jar:1.1.7.RELEASE]
    at org.springframework.cloud.netflix.ribbon.RibbonLoadBalancerClient.execute(RibbonLoadBalancerClient.java:98) ~[spring-cloud-netflix-core-1.2.5.RELEASE.jar:1.2.5.RELEASE]
    at org.springframework.cloud.client.loadbalancer.RetryLoadBalancerInterceptor$1.doWithRetry(RetryLoadBalancerInterceptor.java:88) ~[spring-cloud-commons-1.1.7.RELEASE.jar:1.1.7.RELEASE]
    at org.springframework.cloud.client.loadbalancer.RetryLoadBalancerInterceptor$1.doWithRetry(RetryLoadBalancerInterceptor.java:76) ~[spring-cloud-commons-1.1.7.RELEASE.jar:1.1.7.RELEASE]
    at org.springframework.retry.support.RetryTemplate.doExecute(RetryTemplate.java:286) ~[spring-retry-1.2.0.RELEASE.jar:na]
    at org.springframework.retry.support.RetryTemplate.execute(RetryTemplate.java:163) ~[spring-retry-1.2.0.RELEASE.jar:na]
    at org.springframework.cloud.client.loadbalancer.RetryLoadBalancerInterceptor.intercept(RetryLoadBalancerInterceptor.java:76) ~[spring-cloud-commons-1.1.7.RELEASE.jar:1.1.7.RELEASE]
    at org.springframework.http.client.InterceptingClientHttpRequest$InterceptingRequestExecution.execute(InterceptingClientHttpRequest.java:86) ~[spring-web-4.3.7.RELEASE.jar:4.3.7.RELEASE]
    at org.springframework.http.client.InterceptingClientHttpRequest.executeInternal(InterceptingClientHttpRequest.java:70) ~[spring-web-4.3.7.RELEASE.jar:4.3.7.RELEASE]
    at org.springframework.http.client.AbstractBufferingClientHttpRequest.executeInternal(AbstractBufferingClientHttpRequest.java:48) ~[spring-web-4.3.7.RELEASE.jar:4.3.7.RELEASE]
    at org.springframework.http.client.AbstractClientHttpRequest.execute(AbstractClientHttpRequest.java:53) ~[spring-web-4.3.7.RELEASE.jar:4.3.7.RELEASE]
    at org.springframework.web.client.RestTemplate.doExecute(RestTemplate.java:652) ~[spring-web-4.3.7.RELEASE.jar:4.3.7.RELEASE]
    at org.springframework.web.client.RestTemplate.execute(RestTemplate.java:613) ~[spring-web-4.3.7.RELEASE.jar:4.3.7.RELEASE]
    at org.springframework.web.client.RestTemplate.getForObject(RestTemplate.java:287) ~[spring-web-4.3.7.RELEASE.jar:4.3.7.RELEASE]
    at hello.UserApplication.hi(UserApplication.java:31) ~[classes/:na]
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_101]
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_101]
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_101]
    at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_101]
    at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:205) ~[spring-web-4.3.7.RELEASE.jar:4.3.7.RELEASE]
    at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:133) ~[spring-web-4.3.7.RELEASE.jar:4.3.7.RELEASE]
    at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:116) ~[spring-webmvc-4.3.7.RELEASE.jar:4.3.7.RELEASE]
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:827) ~[spring-webmvc-4.3.7.RELEASE.jar:4.3.7.RELEASE]
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:738) ~[spring-webmvc-4.3.7.RELEASE.jar:4.3.7.RELEASE]
    at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85) ~[spring-webmvc-4.3.7.RELEASE.jar:4.3.7.RELEASE]
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:963) ~[spring-webmvc-4.3.7.RELEASE.jar:4.3.7.RELEASE]
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:897) ~[spring-webmvc-4.3.7.RELEASE.jar:4.3.7.RELEASE]
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:970) ~[spring-webmvc-4.3.7.RELEASE.jar:4.3.7.RELEASE]
    at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:861) ~[spring-webmvc-4.3.7.RELEASE.jar:4.3.7.RELEASE]
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:622) ~[tomcat-embed-core-8.5.11.jar:8.5.11]
    at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846) ~[spring-webmvc-4.3.7.RELEASE.jar:4.3.7.RELEASE]
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:729) ~[tomcat-embed-core-8.5.11.jar:8.5.11]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:230) ~[tomcat-embed-core-8.5.11.jar:8.5.11]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165) ~[tomcat-embed-core-8.5.11.jar:8.5.11]
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52) ~[tomcat-embed-websocket-8.5.11.jar:8.5.11]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:192) ~[tomcat-embed-core-8.5.11.jar:8.5.11]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165) ~[tomcat-embed-core-8.5.11.jar:8.5.11]
    at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:99) ~[spring-web-4.3.7.RELEASE.jar:4.3.7.RELEASE]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-4.3.7.RELEASE.jar:4.3.7.RELEASE]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:192) ~[tomcat-embed-core-8.5.11.jar:8.5.11]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165) ~[tomcat-embed-core-8.5.11.jar:8.5.11]
    at org.springframework.web.filter.HttpPutFormContentFilter.doFilterInternal(HttpPutFormContentFilter.java:105) ~[spring-web-4.3.7.RELEASE.jar:4.3.7.RELEASE]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-4.3.7.RELEASE.jar:4.3.7.RELEASE]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:192) ~[tomcat-embed-core-8.5.11.jar:8.5.11]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165) ~[tomcat-embed-core-8.5.11.jar:8.5.11]
    at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:81) ~[spring-web-4.3.7.RELEASE.jar:4.3.7.RELEASE]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-4.3.7.RELEASE.jar:4.3.7.RELEASE]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:192) ~[tomcat-embed-core-8.5.11.jar:8.5.11]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165) ~[tomcat-embed-core-8.5.11.jar:8.5.11]
    at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:197) ~[spring-web-4.3.7.RELEASE.jar:4.3.7.RELEASE]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-4.3.7.RELEASE.jar:4.3.7.RELEASE]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:192) ~[tomcat-embed-core-8.5.11.jar:8.5.11]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165) ~[tomcat-embed-core-8.5.11.jar:8.5.11]
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:198) ~[tomcat-embed-core-8.5.11.jar:8.5.11]
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96) [tomcat-embed-core-8.5.11.jar:8.5.11]
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:474) [tomcat-embed-core-8.5.11.jar:8.5.11]
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140) [tomcat-embed-core-8.5.11.jar:8.5.11]
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79) [tomcat-embed-core-8.5.11.jar:8.5.11]
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87) [tomcat-embed-core-8.5.11.jar:8.5.11]
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:349) [tomcat-embed-core-8.5.11.jar:8.5.11]
    at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:783) [tomcat-embed-core-8.5.11.jar:8.5.11]
    at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66) [tomcat-embed-core-8.5.11.jar:8.5.11]
    at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:798) [tomcat-embed-core-8.5.11.jar:8.5.11]
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1434) [tomcat-embed-core-8.5.11.jar:8.5.11]
    at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) [tomcat-embed-core-8.5.11.jar:8.5.11]
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) [na:1.8.0_101]
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) [na:1.8.0_101]
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) [tomcat-embed-core-8.5.11.jar:8.5.11]
    at java.lang.Thread.run(Thread.java:745) [na:1.8.0_101]

我错过了什么？预期的行为是，在ping无法关闭服务器之后，客户端应用程序将忽略这些服务器并且不再向它们发送请求。

由于

5 个答案:

答案 0 :(得分：1)

如教程中所述，这是一个简化的例子：

  

功能区中的负载平衡器通常从a获取其服务器列表   Netflix Eureka服务注册表......出于我们这里的简单目的，我们正在跳过Eureka

您的应用程序无法知道您的服务器不再可用。这是服务注册表（例如eureka）的工作，它可以通过心跳机制处理发现哪些服务死或活的工作......

答案 1 :(得分：1)

调试BaseLoadBalancer后，我意识到以下事情： 功能区从列表中ping所有服务器实例，并确定其中哪些已经死亡。 Ribbon在SerialPingStrategy中执行，它是IPingStrategy的默认实现。处理这些ping结果，并且如果至少存在其中一些，则将自上次ping过程以来状态已更改的服务器列表发送到ServerStatusChangeListener实例。但是在给定的教程中没有提供任何实现。我想如果你提供ServerStatusChangeListener的一些实现并将其添加到应用程序上下文中，那么可能会有不同的行为。

答案 2 :(得分：1)

好的，所以我遇到了这个问题，这就是我试图解决它的方法。不确定这是否是理想的选择，但这似乎足以满足我的需求。

IPing实现仅有助于确定服务器是活还是死。它不会从可用服务器列表中删除服务器。

根据Javadoc here，看起来像Ribbon留下了客户决定何时将服务器标记为不健康的决定。这似乎是一个安全的选择。服务器是否应该标记为不可用，如果它失败1 ping和3 ping并且应该在ping时有退避 - 所有这些都取决于你手头的应用程序类型，所以只有客户才能做到安全选择。

但是，没有明确的指示如何在Spring Cloud Netflix的上下文中将ServerStatusChangeListener添加到负载均衡器。所以，我认为如果我们有这种能力，那么这将是从听众中调用BaseLoadBalancer.markServerDown(Server)的正确位置。 Spring Cloud guru（@spencergibb）可以在这里权衡。

继续讨论我如何实施我的解决方案。除了IPing之外，我还配置了一个IRule，并从com.netflix.loadbalancer.AvailabilityFilteringRule扩展了我的规则。由于此规则会过滤掉电路跳闸的服务器，因此您唯一需要添加的是检查服务器本身是否处于活动状态，然后再将其作为所选服务器返回。

@Configuration
public class MyLoadBalancerConfig {

    @Bean
    public IRule ribbonRule(IClientConfig config) {
        return new AvailabilityBasedServerSelectionRule();
    }

    @Bean
    public IPing ribbonPing() {
        return server -> {
            try {
                // TODO: ping your server to decide if health check has passed or not
                Thread.sleep(2000);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }

            return true;
        };
    }

    @Bean
    public ServerList<Server> ribbonServerList(IClientConfig config) {
        return new ServerList<Server>() {
            @Override
            public List<Server> getInitialListOfServers() {
                Server server1 = new Server("server1");
                Server server2 = new Server("server2");
                return new ArrayList<>(Arrays.asList(server1, server2));
            }

            @Override
            public List<Server> getUpdatedListOfServers() {
                Server server3 = new Server("server3");
                Server server4 = new Server("server4");

                return new ArrayList<>(Arrays.asList(server3, server4));
            }
        };
    }
}

和

public class AvailabilityBasedServerSelectionRule extends AvailabilityFilteringRule {

    @Override
    public Server choose(Object key) {

        Server chosenServer = super.choose(key);

        int count = 1;
        List<Server> reachableServers = this.getLoadBalancer().getReachableServers();
        List<Server> allServers = this.getLoadBalancer().getAllServers();

        if(reachableServers.size() > 0) {
            while(!reachableServers.contains(chosenServer) && count++ < allServers.size()) {
                chosenServer = super.choose(key);
            }
        }

        System.out.println("chosenServer.isAlive() = " + chosenServer.isAlive());
        return chosenServer;
    }
}

因此，AvailabilityBasedServerSelectionRule始终返回活动且非电路跳闸的服务器。我还没有发现这种解决方案的任何问题。我会更新这篇文章，如果我发现任何这个方法，我会继续这个方法。祝你好运！

答案 3 :(得分：0)

PingUrl对于您在属性listOfServers中指示的所有服务器，尝试解析服务器是否存在：
localhost:8090，localhost:9092，localhost:9999 因此您必须启动所有服务或删除不需要的服务

这就是所有人！

答案 4 :(得分：0)

如果不存在，您可以告诉功能区重试下一个服务器：

say-hello:
  ribbon:
    MaxAutoRetriesNextServer: 1

使用尤里卡时也可以使用。由于服务注册表会删除延迟的服务器（如果它们不崩溃也不注销）。

此外，您需要添加以下依赖项：

<dependency>
    <groupId>org.springframework.retry</groupId>
    <artifactId>spring-retry</artifactId>
</dependency>
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