java - Eureka - 在本地主机上工作，但在不同主机上时出现问题

Question

我正在尝试使用 Netflix Eureka 来帮助管理服务。我首先开发一个简单的 Eureka 服务器，然后开发两个服务:客户端和服务器。服务器提供客户端将调用的 REST 端点。

当我在本地主机上运行所有内容时，一切都运行良好。服务将自身注册到 eureka 服务器，并且客户端成功调用服务器。当我在浏览器中打开 http://localhost:8761 时，我得到了我期望看到的内容:

然后我决定通过将这些应用程序分离到单独的机器上(这些是由 vagrant 管理的 Linux VM)来使其更加现实。据我所知，服务器和客户端正在向 eureka-server 注册自己，但我无法让客户端成功调用服务器。

根据我在搜索中发现的内容，传递给 RestTemplate 实例以进行 REST 调用的 URL 只需指定要调用的服务的“ID”。不需要主机名、IP 地址或端口 - 这就是重点，是吗？

看起来很接近，但不起作用。我想知道为什么(以及我必须做什么才能使其正常工作)。

这是代码。

Eureka 服务器

EurekaServiceApplication.java

@EnableEurekaServer
@SpringBootApplication
public class EurekaServiceApplication {
  public static void main(String[] args) {
    SpringApplication.run(EurekaServiceApplication.class, args);
  }
}

application.yml:

server:
  port: 8761

eureka:
  client:
    register-with-eureka: false
    fetch-registry: false

logging:
  level:
    com:
      netflix:
        eureka: OFF
        discovery: OFF

没有比这更简单的了。

服务器

ApplicationMain.java:

@EnableDiscoveryClient
@SpringBootApplication
public class ApplicationMain {
  public static void main(String[] args) {
    SpringApplication.run(ApplicationMain.class, args);
  }
}

服务器.java:

@Service
public class Server {
  private final Logger                   logger = LogManager.getLogger();
  @Autowired
  private ConfigurableApplicationContext context;

  public String getID() {
    return "server";
  }
}

服务器 Controller .java:

@RestController
@RequestMapping("/v1/server")
public class ServerController {

  @Autowired
  private Server          service;
  @Autowired
  private DiscoveryClient dicoveryClient;

  @GetMapping(value = "/id", produces = {MediaType.APPLICATION_JSON_VALUE})
  public DeferredResult<ResponseEntity<GeneralResponse>> getID() {
    DeferredResult<ResponseEntity<GeneralResponse>> result = new DeferredResult<>();
    GeneralResponse genResp = new GeneralResponse();
    genResp.setMessage(service.getID());
    result.setResult(ResponseEntity.ok(genResp));
    return result;
  }

  @RequestMapping("/instances")
  public List<ServiceInstance> instances() {
    return dicoveryClient.getInstances("SERVER");
  }

}

bootstrap.yml:

spring:
  application:
    name: server

application.yml:

server:
  port: 8091

eureka:
  client:
    serviceUrl:
      defaultZone: http://localhost:8761/eureka

客户端

ApplicationMain.java:

@EnableDiscoveryClient
@SpringBootApplication
public class ApplicationMain {
  public static void main(String[] args) {
    SpringApplication.run(ApplicationMain.class, args);
  }
}

客户端.java:

@Service
public class Client {

  private final Logger logger = LogManager.getLogger();

  @Autowired
  private RestTemplate restTemplate;

  @Scheduled(fixedRateString = "10000")
  public void callServer() {
    String url = "http://server/v1/server/id";
    ResponseEntity<GeneralResponse> response =
        restTemplate.getForEntity(url, GeneralResponse.class);
    logger.info("response: {}", response.getBody().getMessage());
  }

}

bootstrap.yml:

spring:
  application:
    name: client

application.yml:

server:
  port: 8092

eureka:
  client:
    serviceUrl:
      defaultZone: http://localhost:8761/eureka

对于在三台独立计算机上运行这些应用程序的情况，我编辑服务器和客户端的 application.yml，将 localhost 更改为服务器和客户端的 IP 地址运行 eureka 服务器的机器。

这是客户端抛出的异常:

2019-11-27 14:34:11.991  INFO 11807 --- [   scheduling-1] c.n.l.BaseLoadBalancer                   : Client: server instantiated a LoadBalancer: DynamicServerListLoadBalancer:{NFLoadBalancer:name=server,current list of Servers=[],Load balancer stats=Zone stats: {},Server stats: []}ServerList:null
2019-11-27 14:34:12.000  INFO 11807 --- [   scheduling-1] c.n.l.DynamicServerListLoadBalancer      : Using serverListUpdater PollingServerListUpdater
2019-11-27 14:34:12.038  INFO 11807 --- [   scheduling-1] c.n.c.ChainedDynamicProperty             : Flipping property: server.ribbon.ActiveConnectionsLimit to use NEXT property: niws.loadbalancer.availabilityFilteringRule.activeConnectionsLimit = 2147483647
2019-11-27 14:34:12.041  INFO 11807 --- [   scheduling-1] c.n.l.DynamicServerListLoadBalancer      : DynamicServerListLoadBalancer for client server initialized: DynamicServerListLoadBaActive connections count: 0;servCircuit breaker tripped count: 0;host:80Active connections per server: 0.0;]{defaultzone=[Zone:defaultzone;     Instance },Server stats: average resp time:0.0;1;90 percentile resp time:0.0;tion95 percentile resp time:0.0;ST 1min resp time:0.0;nectiomax resp time:0.0;ure costddev resp time:0.0]
]}ServerList:org.springframework.cloud.netflix.ribbon.eureka.DomainExtractingServerList@af0e207
2019-11-27 14:34:12.098 ERROR 11807 --- [   scheduling-1] o.s.s.s.TaskUtils$LoggingErrorHandler    : Unexpected error occurred in scheduled task.

org.springframework.web.client.ResourceAccessException: I/O error on GET request for "http://server/v1/server/id": Connection refused (Connection refused); nested exception is java.net.ConnectException: Connection refused (Connection refused)
        at org.springframework.web.client.RestTemplate.doExecute(RestTemplate.java:744) ~[spring-web-5.1.8.RELEASE.jar:5.1.8.RELEASE]
        at org.springframework.web.client.RestTemplate.execute(RestTemplate.java:670) ~[spring-web-5.1.8.RELEASE.jar:5.1.8.RELEASE]
        at org.springframework.web.client.RestTemplate.getForEntity(RestTemplate.java:338) ~[spring-web-5.1.8.RELEASE.jar:5.1.8.RELEASE]
        at com.example.Client.callServer(Client.java:66) ~[client-0.0.1-SNAPSHOT.jar:0.0.1-SNAPSHOT]
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_232]
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[?:1.8.0_232]
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:1.8.0_232]
        at java.lang.reflect.Method.invoke(Method.java:498) ~[?:1.8.0_232]
        at org.springframework.scheduling.support.ScheduledMethodRunnable.run(ScheduledMethodRunnable.java:84) ~[spring-context-5.1.8.RELEASE.jar:5.1.8.RELEASE]
        at org.springframework.scheduling.support.DelegatingErrorHandlingRunnable.run(DelegatingErrorHandlingRunnable.java:54) [spring-context-5.1.8.RELEASE.jar:5.1.8.RELEASE]
        at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) [?:1.8.0_232]
        at java.util.concurrent.FutureTask.runAndReset(FutureTask.java:308) [?:1.8.0_232]
        at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$301(ScheduledThreadPoolExecutor.java:180) [?:1.8.0_232]
        at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:294) [?:1.8.0_232]
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) [?:1.8.0_232]
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) [?:1.8.0_232]
        at java.lang.Thread.run(Thread.java:748) [?:1.8.0_232]
Caused by: java.net.ConnectException: Connection refused (Connection refused)
        at java.net.PlainSocketImpl.socketConnect(Native Method) ~[?:1.8.0_232]
        at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:350) ~[?:1.8.0_232]
        at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:206) ~[?:1.8.0_232]
        at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:188) ~[?:1.8.0_232]
        at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392) ~[?:1.8.0_232]
        at java.net.Socket.connect(Socket.java:607) ~[?:1.8.0_232]
        at java.net.Socket.connect(Socket.java:556) ~[?:1.8.0_232]
        at sun.net.NetworkClient.doConnect(NetworkClient.java:180) ~[?:1.8.0_232]
        at sun.net.www.http.HttpClient.openServer(HttpClient.java:463) ~[?:1.8.0_232]
        at sun.net.www.http.HttpClient.openServer(HttpClient.java:558) ~[?:1.8.0_232]
        at sun.net.www.http.HttpClient.<init>(HttpClient.java:242) ~[?:1.8.0_232]
        at sun.net.www.http.HttpClient.New(HttpClient.java:339) ~[?:1.8.0_232]
        at sun.net.www.http.HttpClient.New(HttpClient.java:357) ~[?:1.8.0_232]
        at sun.net.www.protocol.http.HttpURLConnection.getNewHttpClient(HttpURLConnection.java:1226) ~[?:1.8.0_232]
        at sun.net.www.protocol.http.HttpURLConnection.plainConnect0(HttpURLConnection.java:1162) ~[?:1.8.0_232]
        at sun.net.www.protocol.http.HttpURLConnection.plainConnect(HttpURLConnection.java:1056) ~[?:1.8.0_232]
        at sun.net.www.protocol.http.HttpURLConnection.connect(HttpURLConnection.java:990) ~[?:1.8.0_232]
        at org.springframework.http.client.SimpleBufferingClientHttpRequest.executeInternal(SimpleBufferingClientHttpRequest.java:76) ~[spring-web-5.1.8.RELEASE.jar:5.1.8.RELEASE]
        at org.springframework.http.client.AbstractBufferingClientHttpRequest.executeInternal(AbstractBufferingClientHttpRequest.java:48) ~[spring-web-5.1.8.RELEASE.jar:5.1.8.RELEASE]
        at org.springframework.http.client.AbstractClientHttpRequest.execute(AbstractClientHttpRequest.java:53) ~[spring-web-5.1.8.RELEASE.jar:5.1.8.RELEASE]
        at org.springframework.http.client.InterceptingClientHttpRequest$InterceptingRequestExecution.execute(InterceptingClientHttpRequest.java:108) ~[spring-web-5.1.8.RELEASE.jar:5.1.8.RELEASE]
        at org.springframework.cloud.client.loadbalancer.LoadBalancerRequestFactory.lambda$createRequest$0(LoadBalancerRequestFactory.java:59) ~[spring-cloud-commons-2.0.2.RELEASE.jar:2.0.2.RELEASE]
        at org.springframework.cloud.netflix.ribbon.RibbonLoadBalancerClient.execute(RibbonLoadBalancerClient.java:112) ~[spring-cloud-netflix-ribbon-2.0.2.RELEASE.jar:2.0.2.RELEASE]
        at org.springframework.cloud.netflix.ribbon.RibbonLoadBalancerClient.execute(RibbonLoadBalancerClient.java:94) ~[spring-cloud-netflix-ribbon-2.0.2.RELEASE.jar:2.0.2.RELEASE]
        at org.springframework.cloud.client.loadbalancer.LoadBalancerInterceptor.intercept(LoadBalancerInterceptor.java:55) ~[spring-cloud-commons-2.0.2.RELEASE.jar:2.0.2.RELEASE]
        at org.springframework.http.client.InterceptingClientHttpRequest$InterceptingRequestExecution.execute(InterceptingClientHttpRequest.java:92) ~[spring-web-5.1.8.RELEASE.jar:5.1.8.RELEASE]
        at org.springframework.http.client.InterceptingClientHttpRequest.executeInternal(InterceptingClientHttpRequest.java:76) ~[spring-web-5.1.8.RELEASE.jar:5.1.8.RELEASE]
        at org.springframework.http.client.AbstractBufferingClientHttpRequest.executeInternal(AbstractBufferingClientHttpRequest.java:48) ~[spring-web-5.1.8.RELEASE.jar:5.1.8.RELEASE]
        at org.springframework.http.client.AbstractClientHttpRequest.execute(AbstractClientHttpRequest.java:53) ~[spring-web-5.1.8.RELEASE.jar:5.1.8.RELEASE]
        at org.springframework.web.client.RestTemplate.doExecute(RestTemplate.java:735) ~[spring-web-5.1.8.RELEASE.jar:5.1.8.RELEASE]
        ... 16 more

更新:

ClientConfig.java:

@Configuration
@EnableScheduling
public class ClientConfig {
  @Bean
  @LoadBalanced
  public RestTemplate restTemplate() {
    return new RestTemplate();
  }
}

更新:

我的工作环境有一个网络代理，已知该代理过去会导致连接问题。经过更多研究后，我发现有一些 Eureka 属性允许指定代理服务器。

因此，我设置了以下 Eureka 属性，看看是否有帮助。但事实并非如此。

eureka:
  client:
    register-with-eureka: false
    fetch-registry: false
    proxy-host: <proxy server>
    proxy-port: <proxy port>

Answer 1

您必须将 RestTemplate @Bean 声明为 @LoadBalanced

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

您在 @Autowired RestTemplate 上有 @LoadBalanced 注释，但它不执行任何操作