如何使用功能区客户端修复没有可用于微服务的实例

【问题标题】：How to fix no instance available for micro service using ribbon client如何使用功能区客户端修复没有可用于微服务的实例
【发布时间】：2020-07-26 01:05:03
【问题描述】：

我正在使用功能区客户端进行客户端负载平衡。我正在实施微服务 spring boot 2.2.6.RELEASE。 我有 CHAT-BOOK 和 USER-APP 两个微服务。我在 pom.xml 中的 CHAT-BOOK (spring-boot-starter-web, spring-cloud-starter-netflix-ribbon) USER-APP 微服务中添加了所需的依赖项 (spring-boot-starter-web)。 

CHAT-BOOK microservice:

@RestController
@RequestMapping("/chatbook")
public class ChatbookController {

    @Value("${server.port}")
    private String port;

    @GetMapping("/chatnow")
    public String chat() {
        return "application up on port: " + port;
    }
}

USER-APP microservice:

I have added below properties in application.properties.

CHAT-BOOK.ribbon.listOfServers=localhost:8081,localhost:8082,localhost:8083

CHAT-BOOK.ribbon.eureka.enabled=false
server.port=9090

UserAppApplication class:

@SpringBootApplication

@RibbonClient(name = "CHAT-BOOK", configuration = RibbonConfiguration.class)

public class UserAppApplication {


    @Bean
    @LoadBalanced
    public RestTemplate getTemplate() {
        return new RestTemplate();
    }

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

}

RibbonConfiguration.java

public class RibbonConfiguration {

    @Autowired
    IClientConfig ribbonClient;

    @Bean
    public IPing ping(IClientConfig ribbonClient) {
        return new PingUrl();
    }

    @Bean
    public IRule rule(IClientConfig ribbonClient) {
        return new AvailabilityFilteringRule();
    }
}


UserContoller.java 

@RestController
public class UserContoller {

    @Autowired
    private RestTemplate template;

    @GetMapping("/invoke")
    public String invokeChatbook() {
        String url = "http://CHAT-BOOK/chatbook/chatnow";
        return template.getForObject(url, String.class);
    }

}

参考网址：

https://www.youtube.com/watch?v=ueyVjOnDHYQ&list=PLVz2XdJiJQxz3L2Onpxbel6r72IDdWrJh&index=3

当我在应用程序上方运行时，我遇到以下错误。

2020-04-14 11:27:50.013  WARN 9996 --- [nio-9090-exec-5] com.netflix.loadbalancer.RoundRobinRule  : No up servers available from load balancer: DynamicServerListLoadBalancer:{NFLoadBalancer:name=CHAT-BOOK,current list of Servers=[localhost:8081, localhost:8082, localhost:8083],Load balancer stats=Zone stats: {unknown=[Zone:unknown;   Instance count:3;   Active connections count: 0;    Circuit breaker tripped count: 0;   Active connections per server: 0.0;]
},Server stats: [[Server:localhost:8081;    Zone:UNKNOWN;   Total Requests:0;   Successive connection failure:0;    Total blackout seconds:0;   Last connection made:Thu Jan 01 05:30:00 IST 1970;  First connection made: Thu Jan 01 05:30:00 IST 1970;    Active Connections:0;   total failure count in last (1000) msecs:0; average resp time:0.0;  90 percentile resp time:0.0;    95 percentile resp time:0.0;    min resp time:0.0;  max resp time:0.0;  stddev resp time:0.0]
, [Server:localhost:8082;   Zone:UNKNOWN;   Total Requests:0;   Successive connection failure:0;    Total blackout seconds:0;   Last connection made:Thu Jan 01 05:30:00 IST 1970;  First connection made: Thu Jan 01 05:30:00 IST 1970;    Active Connections:0;   total failure count in last (1000) msecs:0; average resp time:0.0;  90 percentile resp time:0.0;    95 percentile resp time:0.0;    min resp time:0.0;  max resp time:0.0;  stddev resp time:0.0]
, [Server:localhost:8083;   Zone:UNKNOWN;   Total Requests:0;   Successive connection failure:0;    Total blackout seconds:0;   Last connection made:Thu Jan 01 05:30:00 IST 1970;  First connection made: Thu Jan 01 05:30:00 IST 1970;    Active Connections:0;   total failure count in last (1000) msecs:0; average resp time:0.0;  90 percentile resp time:0.0;    95 percentile resp time:0.0;    min resp time:0.0;  max resp time:0.0;  stddev resp time:0.0]
]}ServerList:com.netflix.loadbalancer.ConfigurationBasedServerList@387e7238
2020-04-14 11:27:50.016  WARN 9996 --- [nio-9090-exec-5] c.netflix.loadbalancer.BaseLoadBalancer  : LoadBalancer [CHAT-BOOK]:  Error choosing server for key default

我运行三台服务器（8081、8082、8083）。但它显示负载均衡器没有可用的服务器。

错误1：

java.lang.NullPointerException: null
    at com.google.common.base.Preconditions.checkNotNull(Preconditions.java:890) ~[guava-28.2-android.jar:na]
    at com.google.common.cache.LocalCache.get(LocalCache.java:3848) ~[guava-28.2-android.jar:na]
    at com.google.common.cache.LocalCache.getOrLoad(LocalCache.java:3873) ~[guava-28.2-android.jar:na]
    at com.google.common.cache.LocalCache$LocalLoadingCache.get(LocalCache.java:4798) ~[guava-28.2-android.jar:na]
    at com.netflix.loadbalancer.LoadBalancerStats.getServerStats(LoadBalancerStats.java:185) ~[ribbon-loadbalancer-2.3.0.jar:2.3.0]
    at com.netflix.loadbalancer.LoadBalancerStats.getSingleServerStat(LoadBalancerStats.java:372) ~[ribbon-loadbalancer-2.3.0.jar:2.3.0]
    at com.netflix.loadbalancer.AvailabilityPredicate.apply(AvailabilityPredicate.java:73) ~[ribbon-loadbalancer-2.3.0.jar:2.3.0]
    at com.netflix.loadbalancer.AvailabilityPredicate.apply(AvailabilityPredicate.java:35) ~[ribbon-loadbalancer-2.3.0.jar:2.3.0]
    at com.netflix.loadbalancer.CompositePredicate.apply(CompositePredicate.java:52) ~[ribbon-loadbalancer-2.3.0.jar:2.3.0]
    at com.netflix.loadbalancer.CompositePredicate.apply(CompositePredicate.java:40) ~[ribbon-loadbalancer-2.3.0.jar:2.3.0]
    at com.netflix.loadbalancer.AvailabilityFilteringRule.choose(AvailabilityFilteringRule.java:86) ~[ribbon-loadbalancer-2.3.0.jar:2.3.0]
    at com.netflix.loadbalancer.BaseLoadBalancer.chooseServer(BaseLoadBalancer.java:755) ~[ribbon-loadbalancer-2.3.0.jar:2.3.0]
    at com.netflix.loadbalancer.ZoneAwareLoadBalancer.chooseServer(ZoneAwareLoadBalancer.java:113) [ribbon-loadbalancer-2.3.0.jar:2.3.0]
    at org.springframework.cloud.netflix.ribbon.RibbonLoadBalancerClient.getServer(RibbonLoadBalancerClient.java:189) [spring-cloud-netflix-ribbon-2.2.2.RELEASE.jar:2.2.2.RELEASE]....

错误2：

java.lang.IllegalStateException: No instances available for CHAT-BOOK
    at org.springframework.cloud.netflix.ribbon.RibbonLoadBalancerClient.execute(RibbonLoadBalancerClient.java:119) ~[spring-cloud-netflix-ribbon-2.2.2.RELEASE.jar:2.2.2.RELEASE]
    at org.springframework.cloud.netflix.ribbon.RibbonLoadBalancerClient.execute(RibbonLoadBalancerClient.java:99) ~[spring-cloud-netflix-ribbon-2.2.2.RELEASE.jar:2.2.2.RELEASE]
    at org.springframework.cloud.client.loadbalancer.LoadBalancerInterceptor.intercept(LoadBalancerInterceptor.java:58) ~[spring-cloud-commons-2.2.2.RELEASE.jar:2.2.2.RELEASE]
    at org.springframework.http.client.InterceptingClientHttpRequest$InterceptingRequestExecution.execute(InterceptingClientHttpRequest.java:93) ~[spring-web-5.2.5.RELEASE.jar:5.2.5.RELEASE]
    at org.springframework.http.client.InterceptingClientHttpRequest.executeInternal(InterceptingClientHttpRequest.java:77) ~[spring-web-5.2.5.RELEASE.jar:5.2.5.RELEASE]
    at org.springframework.http.client.AbstractBufferingClientHttpRequest.executeInternal(AbstractBufferingClientHttpRequest.java:48) ~[spring-web-5.2.5.RELEASE.jar:5.2.5.RELEASE]
    at org.springframework.http.client.AbstractClientHttpRequest.execute(AbstractClientHttpRequest.java:53) ~[spring-web-5.2.5.RELEASE.jar:5.2.5.RELEASE]
    at org.springframework.web.client.RestTemplate.doExecute(RestTemplate.java:739) ~[spring-web-5.2.5.RELEASE.jar:5.2.5.RELEASE]
    at org.springframework.web.client.RestTemplate.execute(RestTemplate.java:674) ~[spring-web-5.2.5.RELEASE.jar:5.2.5.RELEASE]
    at org.springframework.web.client.RestTemplate.getForObject(RestTemplate.java:315) ~[spring-web-5.2.5.RELEASE.jar:5.2.5.RELEASE]
    at com.loadbalanced.api.UserContoller.invokeChatbook(UserContoller.java:17) ~[classes/:na]
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_231]
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) ~[na:1.8.0_231]
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[na:1.8.0_231]
    at java.lang.reflect.Method.invoke(Unknown Source) ~[na:1.8.0_231]
    at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:190) ~[spring-web-5.2.5.RELEASE.jar:5.2.5.RELEASE]
    at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:138) ~[spring-web-5.2.5.RELEASE.jar:5.2.5.RELEASE]
    at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:105) ~[spring-webmvc-5.2.5.RELEASE.jar:5.2.5.RELEASE]
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:879) ~[spring-webmvc-5.2.5.RELEASE.jar:5.2.5.RELEASE]
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:793) ~[spring-webmvc-5.2.5.RELEASE.jar:5.2.5.RELEASE]
    at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87) ~[spring-webmvc-5.2.5.RELEASE.jar:5.2.5.RELEASE]
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1040) ~[spring-webmvc-5.2.5.RELEASE.jar:5.2.5.RELEASE]
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:943) ~[spring-webmvc-5.2.5.RELEASE.jar:5.2.5.RELEASE]
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006) ~[spring-webmvc-5.2.5.RELEASE.jar:5.2.5.RELEASE]
    at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:898) ~[spring-webmvc-5.2.5.RELEASE.jar:5.2.5.RELEASE]
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:634) ~[tomcat-embed-core-9.0.33.jar:9.0.33].....

任何人都可以建议我如何解决上述问题。

提前致谢

【问题讨论】：

  • 您对功能区引用的配置chatbook 但您将功能区客户端命名为CHAT-BOOK，它们应该是相同的。
  • 我改名为 CHAT-BOOK。我运行应用程序，但我遇到了同样的问题。我观察到我的三台服务器已启动的一件事，然后它还显示“Loadbalancer 没有可用的服务器”。你能检查一下我的问题吗？我添加了更多信息。
  • 您的服务是否响应对/ 的根请求？如果不删除PingUrl?
  • 我在 RibbonConfiguration 中删除了 pingurl bean。现在我的应用程序成功运行。非常感谢您的宝贵时间和建议。

标签： java spring-boot microservices spring-cloud netflix-ribbon


【解决方案1】：

由于您已将策略指定为 PingUrl，因此您需要在服务中为“/”添加 @RequestMapping，以便 Ribbon 可以 ping 以了解实例的可用性：

@RequestMapping(value = "/")
      public String home() {
        return "home";
      }

【讨论】：

    【解决方案2】：
    【解决方案3】：

    看起来服务没有通过尤里卡解决。请检查这些是否已在 eureka 中注册，并检查以下属性是否未禁用 eureka

    CHAT-BOOK.ribbon.eureka.enabled=false

    如果您不使用 eureka，请设置以下属性

        CHAT-BOOK.ribbon.eureka.enabled=false
    CHAT-BOOK.ribbon.NIWSServerListClassName=com.netflix.loadbalancer.ConfigurationBasedServerList
    CHAT-BOOK.ribbon.listOfServers=http://localhost:9999/

    【讨论】：

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