spring 负载均衡器没有可供客户端使用的服务器
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Load balancer does not have available server for client
提问by Yogen Rai
I'm trying to use Feign client. Below is my feing client:
我正在尝试使用 Feign 客户端。以下是我的客户：
import com.eprogrammerz.examples.domain.Movie;
import org.springframework.cloud.netflix.feign.FeignClient;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
/**
* Created by Yogen on 12/26/2016.
*/
@FeignClient(name = "movie-api")
public interface MovieApi {
@RequestMapping(method = RequestMethod.GET, value = "/movies/{id}")
Movie getMovie(@PathVariable("id") Long id);
}
I'm calling it from simple service as below:
我从简单的服务中调用它，如下所示：
@Service
public class MovieService {
@Autowired
MovieApi movieApi;
public Movie findMovie(Long id){
Movie movieOfTheDay = movieApi.getMovie(id);
return movieOfTheDay;
}
}
My spring boot app is as below:
我的春季启动应用程序如下：
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.circuitbreaker.EnableCircuitBreaker;
import org.springframework.cloud.netflix.feign.EnableFeignClients;
@EnableFeignClients(basePackages = {"com.eprogrammerz.examples"})
@EnableCircuitBreaker
@SpringBootApplication
public class ClientAppApplication {
public static void main(String[] args) {
SpringApplication.run(ClientAppApplication.class, args);
}
}
build.gradle
构建.gradle
buildscript {
ext {
springBootVersion = '1.4.3.RELEASE'
}
repositories {
jcenter()
mavenCentral()
}
dependencies {
classpath("org.springframework.boot:spring-boot-gradle-plugin:${springBootVersion}")
}
}
apply plugin: 'java'
apply plugin: 'eclipse'
apply plugin: 'org.springframework.boot'
jar {
baseName = 'client-app'
version = '0.0.1-SNAPSHOT'
}
sourceCompatibility = 1.8
targetCompatibility = 1.8
repositories {
jcenter()
mavenCentral()
maven { url "https://repo.spring.io/snapshot" }
maven { url "https://repo.spring.io/milestone" }
}
dependencies {
compile('org.springframework.cloud:spring-cloud-starter-feign')
// https://mvnrepository.com/artifact/com.netflix.hystrix/hystrix-core
compile('org.springframework.cloud:spring-cloud-starter-hystrix')
compile("org.springframework.boot:spring-boot-starter-web"){
exclude group: 'org.springframework.boot', module: 'spring-boot-starter-logging'
}
compileOnly('org.projectlombok:lombok')
testCompile('org.springframework.boot:spring-boot-starter-test')
}
dependencyManagement {
imports {
mavenBom "org.springframework.cloud:spring-cloud-dependencies:Camden.BUILD-SNAPSHOT"
mavenBom "org.springframework.boot:spring-boot-starter-parent:${springBootVersion}"
}
}
I'm getting error as below:
我收到如下错误：
2016-12-30 13:07:16.894 INFO 6748 --- [nio-8082-exec-1] o.s.web.servlet.DispatcherServlet : FrameworkServlet 'dispatcherServlet': initialization completed in 39 ms
2016-12-30 13:07:16.939 INFO 6748 --- [nio-8082-exec-1] c.e.e.controllers.RequestController : Calling findMovie(1203)
2016-12-30 13:07:17.240 INFO 6748 --- [rix-movie-api-1] s.c.a.AnnotationConfigApplicationContext : Refreshing org.springframework.context.annotation.AnnotationConfigApplicationContext@547496c2: startup date [Fri Dec 30 13:07:17 EST 2016]; parent: org.springframework.boot.context.embedded.AnnotationConfigEmbeddedWebApplicationContext@542e560f
2016-12-30 13:07:17.318 INFO 6748 --- [rix-movie-api-1] f.a.AutowiredAnnotationBeanPostProcessor : JSR-330 'javax.inject.Inject' annotation found and supported for autowiring
2016-12-30 13:07:17.619 INFO 6748 --- [rix-movie-api-1] c.netflix.config.ChainedDynamicProperty : Flipping property: movie-api.ribbon.ActiveConnectionsLimit to use NEXT property: niws.loadbalancer.availabilityFilteringRule.activeConnectionsLimit = 2147483647
2016-12-30 13:07:17.670 INFO 6748 --- [rix-movie-api-1] c.n.u.concurrent.ShutdownEnabledTimer : Shutdown hook installed for: NFLoadBalancer-PingTimer-movie-api
2016-12-30 13:07:17.727 INFO 6748 --- [rix-movie-api-1] c.netflix.loadbalancer.BaseLoadBalancer : Client:movie-api instantiated a LoadBalancer:DynamicServerListLoadBalancer:{NFLoadBalancer:name=movie-api,current list of Servers=[],Load balancer stats=Zone stats: {},Server stats: []}ServerList:null
2016-12-30 13:07:17.739 INFO 6748 --- [rix-movie-api-1] c.n.l.DynamicServerListLoadBalancer : Using serverListUpdater PollingServerListUpdater
2016-12-30 13:07:17.746 INFO 6748 --- [rix-movie-api-1] c.n.l.DynamicServerListLoadBalancer : DynamicServerListLoadBalancer for client movie-api initialized: DynamicServerListLoadBalancer:{NFLoadBalancer:name=movie-api,current list of Servers=[],Load balancer stats=Zone stats: {},Server stats: []}ServerList:com.netflix.loadbalancer.ConfigurationBasedServerList@45bcfd5
2016-12-30 13:07:18.191 ERROR 6748 --- [nio-8082-exec-1] o.a.c.c.C.[.[.[/].[dispatcherServlet] : Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is com.netflix.hystrix.exception.HystrixRuntimeException: MovieApi#getMovie(Long) failed and no fallback available.] with root cause
com.netflix.client.ClientException: Load balancer does not have available server for client: movie-api
at com.netflix.loadbalancer.LoadBalancerContext.getServerFromLoadBalancer(LoadBalancerContext.java:468) ~[ribbon-loadbalancer-2.2.0.jar:2.2.0]
at com.netflix.loadbalancer.reactive.LoadBalancerCommand.call(LoadBalancerCommand.java:184) ~[ribbon-loadbalancer-2.2.0.jar:2.2.0]
at com.netflix.loadbalancer.reactive.LoadBalancerCommand.call(LoadBalancerCommand.java:180) ~[ribbon-loadbalancer-2.2.0.jar:2.2.0]
at rx.Observable.unsafeSubscribe(Observable.java:10211) ~[rxjava-1.1.10.jar:1.1.10]
at rx.internal.operators.OnSubscribeConcatMap.call(OnSubscribeConcatMap.java:94) ~[rxjava-1.1.10.jar:1.1.10]
at rx.internal.operators.OnSubscribeConcatMap.call(OnSubscribeConcatMap.java:42) ~[rxjava-1.1.10.jar:1.1.10]
at rx.Observable.unsafeSubscribe(Observable.java:10211) ~[rxjava-1.1.10.jar:1.1.10]
at rx.internal.operators.OperatorRetryWithPredicate$SourceSubscriber.call(OperatorRetryWithPredicate.java:127) ~[rxjava-1.1.10.jar:1.1.10]
at rx.internal.schedulers.TrampolineScheduler$InnerCurrentThreadScheduler.enqueue(TrampolineScheduler.java:73) ~[rxjava-1.1.10.jar:1.1.10]
at rx.internal.schedulers.TrampolineScheduler$InnerCurrentThreadScheduler.schedule(TrampolineScheduler.java:52) ~[rxjava-1.1.10.jar:1.1.10]
at rx.internal.operators.OperatorRetryWithPredicate$SourceSubscriber.onNext(OperatorRetryWithPredicate.java:79) ~[rxjava-1.1.10.jar:1.1.10]
at rx.internal.operators.OperatorRetryWithPredicate$SourceSubscriber.onNext(OperatorRetryWithPredicate.java:45) ~[rxjava-1.1.10.jar:1.1.10]
at rx.internal.util.ScalarSynchronousObservable$WeakSingleProducer.request(ScalarSynchronousObservable.java:276) ~[rxjava-1.1.10.jar:1.1.10]
at rx.Subscriber.setProducer(Subscriber.java:209) ~[rxjava-1.1.10.jar:1.1.10]
at rx.internal.util.ScalarSynchronousObservable$JustOnSubscribe.call(ScalarSynchronousObservable.java:138) ~[rxjava-1.1.10.jar:1.1.10]
at rx.internal.util.ScalarSynchronousObservable$JustOnSubscribe.call(ScalarSynchronousObservable.java:129) ~[rxjava-1.1.10.jar:1.1.10]
at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:48) ~[rxjava-1.1.10.jar:1.1.10]
at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:30) ~[rxjava-1.1.10.jar:1.1.10]
at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:48) ~[rxjava-1.1.10.jar:1.1.10]
at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:30) ~[rxjava-1.1.10.jar:1.1.10]
at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:48) ~[rxjava-1.1.10.jar:1.1.10]
at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:30) ~[rxjava-1.1.10.jar:1.1.10]
at rx.Observable.subscribe(Observable.java:10307) ~[rxjava-1.1.10.jar:1.1.10]
at rx.Observable.subscribe(Observable.java:10274) ~[rxjava-1.1.10.jar:1.1.10]
at rx.observables.BlockingObservable.blockForSingle(BlockingObservable.java:445) ~[rxjava-1.1.10.jar:1.1.10]
at rx.observables.BlockingObservable.single(BlockingObservable.java:342) ~[rxjava-1.1.10.jar:1.1.10]
at com.netflix.client.AbstractLoadBalancerAwareClient.executeWithLoadBalancer(AbstractLoadBalancerAwareClient.java:102) ~[ribbon-loadbalancer-2.2.0.jar:2.2.0]
at org.springframework.cloud.netflix.feign.ribbon.LoadBalancerFeignClient.execute(LoadBalancerFeignClient.java:63) ~[spring-cloud-netflix-core-1.2.4.BUILD-SNAPSHOT.jar:1.2.4.BUILD-SNAPSHOT]
at feign.SynchronousMethodHandler.executeAndDecode(SynchronousMethodHandler.java:97) ~[feign-core-9.3.1.jar:na]
at feign.SynchronousMethodHandler.invoke(SynchronousMethodHandler.java:76) ~[feign-core-9.3.1.jar:na]
at feign.hystrix.HystrixInvocationHandler.run(HystrixInvocationHandler.java:108) ~[feign-hystrix-9.3.1.jar:na]
at com.netflix.hystrix.HystrixCommand.call(HystrixCommand.java:301) ~[hystrix-core-1.5.6.jar:1.5.6]
at com.netflix.hystrix.HystrixCommand.call(HystrixCommand.java:297) ~[hystrix-core-1.5.6.jar:1.5.6]
at rx.internal.operators.OnSubscribeDefer.call(OnSubscribeDefer.java:46) ~[rxjava-1.1.10.jar:1.1.10]
at rx.internal.operators.OnSubscribeDefer.call(OnSubscribeDefer.java:35) ~[rxjava-1.1.10.jar:1.1.10]
at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:48) ~[rxjava-1.1.10.jar:1.1.10]
at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:30) ~[rxjava-1.1.10.jar:1.1.10]
at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:48) ~[rxjava-1.1.10.jar:1.1.10]
at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:30) ~[rxjava-1.1.10.jar:1.1.10]
at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:48) ~[rxjava-1.1.10.jar:1.1.10]
at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:30) ~[rxjava-1.1.10.jar:1.1.10]
at rx.Observable.unsafeSubscribe(Observable.java:10211) ~[rxjava-1.1.10.jar:1.1.10]
at rx.internal.operators.OnSubscribeDefer.call(OnSubscribeDefer.java:51) ~[rxjava-1.1.10.jar:1.1.10]
at rx.internal.operators.OnSubscribeDefer.call(OnSubscribeDefer.java:35) ~[rxjava-1.1.10.jar:1.1.10]
at rx.Observable.unsafeSubscribe(Observable.java:10211) ~[rxjava-1.1.10.jar:1.1.10]
at rx.internal.operators.OnSubscribeDoOnEach.call(OnSubscribeDoOnEach.java:41) ~[rxjava-1.1.10.jar:1.1.10]
at rx.internal.operators.OnSubscribeDoOnEach.call(OnSubscribeDoOnEach.java:30) ~[rxjava-1.1.10.jar:1.1.10]
at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:48) ~[rxjava-1.1.10.jar:1.1.10]
at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:30) ~[rxjava-1.1.10.jar:1.1.10]
at rx.Observable.unsafeSubscribe(Observable.java:10211) ~[rxjava-1.1.10.jar:1.1.10]
at rx.internal.operators.OperatorSubscribeOn.call(OperatorSubscribeOn.java:94) ~[rxjava-1.1.10.jar:1.1.10]
at com.netflix.hystrix.strategy.concurrency.HystrixContexSchedulerAction.call(HystrixContexSchedulerAction.java:56) ~[hystrix-core-1.5.6.jar:1.5.6]
at com.netflix.hystrix.strategy.concurrency.HystrixContexSchedulerAction.call(HystrixContexSchedulerAction.java:47) ~[hystrix-core-1.5.6.jar:1.5.6]
at com.netflix.hystrix.strategy.concurrency.HystrixContexSchedulerAction.call(HystrixContexSchedulerAction.java:69) ~[hystrix-core-1.5.6.jar:1.5.6]
at rx.internal.schedulers.ScheduledAction.run(ScheduledAction.java:55) ~[rxjava-1.1.10.jar:1.1.10]
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) ~[na:1.8.0_51]
at java.util.concurrent.FutureTask.run(FutureTask.java:266) ~[na:1.8.0_51]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) ~[na:1.8.0_51]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) ~[na:1.8.0_51]
at java.lang.Thread.run(Thread.java:745) [na:1.8.0_51]
I tried different way. But couldn't figure out the solution. I couldn't find any information about this on Spring Cloud Netflixtoo. I couldn't find any information on discussion thread on StackOverflowtoo.
我尝试了不同的方式。但想不出解决办法。我在Spring Cloud Netflix 上也找不到任何关于此的信息。我也找不到有关 StackOverflow上讨论线程的任何信息。
What I'm missing here? TIA.
我在这里缺少什么？TIA。
Further Details:
更多细节：
application.yml for movie-api microservice is as below:
movie-api 微服务的 application.yml 如下：
server:
port: 8090
logging:
config: classpath:log4j2.yml
spring:
application:
name: movie-api
Spring boot app on movie-api module:
电影 API 模块上的 Spring 启动应用程序：
@SpringBootApplication
public class MovieApiApplication {
public static void main(String[] args) {
SpringApplication.run(MovieApiApplication.class, args);
}
}
And controller is as below:
控制器如下：
@RestController
@Slf4j
public class MovieController {
@Autowired
private MovieRepository movieRepository;
@RequestMapping("/movies/{id}")
public ResponseEntity<Movie> getBook(@PathVariable("id") Long id){
log.trace("getBook({})",id);
Optional<Movie> movie = Optional.of(movieRepository.findOneById(id));
if(movie.isPresent())
return new ResponseEntity(movie.get(), HttpStatus.OK);
return new ResponseEntity<Movie>(HttpStatus.NOT_FOUND);
}
}
回答by Yogen Rai
After doing research, and with help of @Bloodysock, I found that I was missing registration of remote server in 'client-app' micro-service. The document is at Spring Cloud Netflix.
经过研究，在@Bloodysock 的帮助下，我发现我在“client-app”微服务中缺少远程服务器的注册。该文档位于Spring Cloud Netflix。
I used Ribbon without Eureka with configuration in application.ymlin 'client-app' micro-service as:
我使用了没有 Eureka 的 Ribbon，application.yml在 ' client-app' 微服务中配置为：
movie-api:
ribbon:
listOfServers: http://localhost:8090
回答by Luciano Nery
The problem is that your service doesn't know the host of requested service. If you are using Eureka, put this line on your .properties or .yml file:
问题是您的服务不知道所请求服务的主机。如果您使用 Eureka，请将这一行放在您的 .properties 或 .yml 文件中：
eureka.client.fetchRegistry=true
eureka.client.fetchRegistry=true
OR
或者
eureka:
client:
fetchRegistry: true
It'll make your service talk with Eureka and discovers host of requested service.
它会让你的服务与 Eureka 对话并发现请求服务的主机。
回答by CodeRider
I nearly wasted 2 hours to find the root cause. I mistakenly imported EnableEurekaClient in client application, which was the root cause for the issue. I finally resolved this issue by removing the import. To my surprise @EnableDiscoveryClient does not require the below dependency. But if you are using Eureka Naming server than this has to be used.
我几乎浪费了 2 个小时来找到根本原因。我错误地在客户端应用程序中导入了 EnableEurekaClient，这是问题的根本原因。我终于通过删除导入解决了这个问题。令我惊讶的是 @EnableDiscoveryClient 不需要以下依赖项。但是，如果您使用的是 Eureka Naming 服务器，则必须使用它。
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
<version>2.0.0.RELEASE</version>
</dependency>
回答by Dexter
If your Spring Cloud set up does not support specifying the servers in application.properties/application.yml, you have to configure the services URL in a Configuration class.
如果您的 Spring Cloud 设置不支持在 application.properties/application.yml 中指定服务器，则必须在 Configuration 类中配置服务 URL。
Pls, note the warning messagein my application.properties [Spring Boot v2.0.0RELEASE, spring-cloud-starter-feign & spring-cloud-starter-ribbon v 1.4.3.RELEASE]
请注意我的 application.properties [Spring Boot v2.0.0RELEASE, spring-cloud-starter-feign & spring-cloud-starter-ribbon v 1.4.3.RELEASE] 中的警告消息
So what I did was to write a Configuration class as follows:
所以我所做的是编写一个 Configuration 类，如下所示：
@Configuration
class LocalRibbonClientConfiguration {
@Bean
public ServerList<Server> ribbonServerList() {
// return new ConfigurationBasedServerList();
StaticServerList<Server> staticServerList = new StaticServerList<>((new Server("localhost", 8001)),
new Server("localhost", 8000));
return staticServerList;
}
}
Then, configured the Spring Boot Application to use this configuration as follows:
然后，将 Spring Boot 应用程序配置为使用此配置，如下所示：
@SpringBootApplication
@EnableFeignClients("my-package.currencyconversionservice")
@RibbonClient(name = "currency-conversion-service", configuration = LocalRibbonClientConfiguration.class)
public class CurrencyConversionServiceApplication {
// nothing new here...
}
No need to change the Feign Proxy class. Posting just for this post to be served as a complete solution to the problem:
无需更改 Feign Proxy 类。发帖只是为了解决这个问题：
@FeignClient(name="currency-exchange-service")
@RibbonClient(name="currency-exchange-service")
public interface CurrencyExchangeServiceProxy {
@GetMapping("/currency-exchange/from/{from}/to/{to}")
public CurrencyConversionBean retrieveExchangeValue(@PathVariable("from") String from, @PathVariable("to") String to);
}
That's all. The problem was fixed.
就这样。问题已解决。
回答by Shikhar Chaudhary
The problem is that your service doesn't know the host of the requested service. If you are using Eureka and zuul, put this line on your zuul .properties or .yml file :
问题是您的服务不知道所请求服务的主机。如果您使用 Eureka 和 zuul，请将此行放在您的 zuul .properties 或 .yml 文件中：
eureka.client.fetch-registry=true
eureka.client.fetch-registry=true
回答by Elie Nehmé
You need to add Ribbon along with Eureka Client, otherwise the service won't be fetched.
您需要将 Ribbon 与 Eureka Client 一起添加，否则将无法获取服务。
in my pom.xml I have:
在我的 pom.xml 我有：
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-netflix-ribbon</artifactId>
</dependency>
And in my service proxy:
在我的服务代理中：
@FeignClient(name = "movie-api")
@RibbonClient(name = "movie-api")
public interface MovieApi {
@RequestMapping(method = RequestMethod.GET, value = "/movies/{id}")
Movie getMovie(@PathVariable("id") Long id);
}
