eureka服务器的客户端(服务消费端)如果在fetchRegistry设置为false的情况下
Feigh一端启动的时候 会报错

eureka:
  client:
    registerWithEureka: true
    fetchRegistry: false

Whitelabel Error Page
This application has no explicit mapping for /error, so you are seeing this as a fallback.

Tue Jan 09 10:08:43 CST 2018
There was an unexpected error (type=Internal Server Error, status=500).
UserService#queryUser(Integer) failed and no fallback available.

com.netflix.client.ClientException: Load balancer does not have available server for client: service-hi
    at com.netflix.loadbalancer.LoadBalancerContext.getServerFromLoadBalancer(LoadBalancerContext.java:483) ~[ribbon-loadbalancer-2.2.4.jar:2.2.4]
    at com.netflix.loadbalancer.reactive.LoadBalancerCommand$1.call(LoadBalancerCommand.java:184) ~[ribbon-loadbalancer-2.2.4.jar:2.2.4]
    at com.netflix.loadbalancer.reactive.LoadBalancerCommand$1.call(LoadBalancerCommand.java:180) ~[ribbon-loadbalancer-2.2.4.jar:2.2.4]
    at rx.Observable.unsafeSubscribe(Observable.java:10151) ~[rxjava-1.2.0.jar:1.2.0]
    at rx.internal.operators.OnSubscribeConcatMap.call(OnSubscribeConcatMap.java:94) ~[rxjava-1.2.0.jar:1.2.0]
    at rx.internal.operators.OnSubscribeConcatMap.call(OnSubscribeConcatMap.java:42) ~[rxjava-1.2.0.jar:1.2.0]
    at rx.Observable.unsafeSubscribe(Observable.java:10151) ~[rxjava-1.2.0.jar:1.2.0]
    at rx.internal.operators.OperatorRetryWithPredicate$SourceSubscriber$1.call(OperatorRetryWithPredicate.java:127) ~[rxjava-1.2.0.jar:1.2.0]
    at rx.internal.schedulers.TrampolineScheduler$InnerCurrentThreadScheduler.enqueue(TrampolineScheduler.java:73) ~[rxjava-1.2.0.jar:1.2.0]
    at rx.internal.schedulers.TrampolineScheduler$InnerCurrentThreadScheduler.schedule(TrampolineScheduler.java:52) ~[rxjava-1.2.0.jar:1.2.0]
    at rx.internal.operators.OperatorRetryWithPredicate$SourceSubscriber.onNext(OperatorRetryWithPredicate.java:79) ~[rxjava-1.2.0.jar:1.2.0]
    at rx.internal.operators.OperatorRetryWithPredicate$SourceSubscriber.onNext(OperatorRetryWithPredicate.java:45) ~[rxjava-1.2.0.jar:1.2.0]
    at rx.internal.util.ScalarSynchronousObservable$WeakSingleProducer.request(ScalarSynchronousObservable.java:276) ~[rxjava-1.2.0.jar:1.2.0]
    at rx.Subscriber.setProducer(Subscriber.java:209) ~[rxjava-1.2.0.jar:1.2.0]
    at rx.internal.util.ScalarSynchronousObservable$JustOnSubscribe.call(ScalarSynchronousObservable.java:138) ~[rxjava-1.2.0.jar:1.2.0]
    at rx.internal.util.ScalarSynchronousObservable$JustOnSubscribe.call(ScalarSynchronousObservable.java:129) ~[rxjava-1.2.0.jar:1.2.0]
    at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:48) ~[rxjava-1.2.0.jar:1.2.0]
    at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:30) ~[rxjava-1.2.0.jar:1.2.0]
    at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:48) ~[rxjava-1.2.0.jar:1.2.0]
    at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:30) ~[rxjava-1.2.0.jar:1.2.0]
    at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:48) ~[rxjava-1.2.0.jar:1.2.0]
    at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:30) ~[rxjava-1.2.0.jar:1.2.0]
    at rx.Observable.subscribe(Observable.java:10247) ~[rxjava-1.2.0.jar:1.2.0]
    at rx.Observable.subscribe(Observable.java:10214) ~[rxjava-1.2.0.jar:1.2.0]
    at rx.observables.BlockingObservable.blockForSingle(BlockingObservable.java:444) ~[rxjava-1.2.0.jar:1.2.0]
    at rx.observables.BlockingObservable.single(BlockingObservable.java:341) ~[rxjava-1.2.0.jar:1.2.0]
    at com.netflix.client.AbstractLoadBalancerAwareClient.executeWithLoadBalancer(AbstractLoadBalancerAwareClient.java:112) ~[ribbon-loadbalancer-2.2.4.jar:2.2.4]
    at org.springframework.cloud.netflix.feign.ribbon.LoadBalancerFeignClient.execute(LoadBalancerFeignClient.java:63) ~[spring-cloud-netflix-core-1.4.0.RELEASE.jar:1.4.0.RELEASE]
    at feign.SynchronousMethodHandler.executeAndDecode(SynchronousMethodHandler.java:97) ~[feign-core-9.5.0.jar:na]
    at feign.SynchronousMethodHandler.invoke(SynchronousMethodHandler.java:76) ~[feign-core-9.5.0.jar:na]
    at feign.hystrix.HystrixInvocationHandler$1.run(HystrixInvocationHandler.java:108) ~[feign-hystrix-9.5.0.jar:na]
    at com.netflix.hystrix.HystrixCommand$2.call(HystrixCommand.java:302) ~[hystrix-core-1.5.12.jar:1.5.12]
    at com.netflix.hystrix.HystrixCommand$2.call(HystrixCommand.java:298) ~[hystrix-core-1.5.12.jar:1.5.12]
    at rx.internal.operators.OnSubscribeDefer.call(OnSubscribeDefer.java:46) ~[rxjava-1.2.0.jar:1.2.0]
    at rx.internal.operators.OnSubscribeDefer.call(OnSubscribeDefer.java:35) ~[rxjava-1.2.0.jar:1.2.0]
    at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:48) ~[rxjava-1.2.0.jar:1.2.0]
    at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:30) ~[rxjava-1.2.0.jar:1.2.0]
    at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:48) ~[rxjava-1.2.0.jar:1.2.0]
    at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:30) ~[rxjava-1.2.0.jar:1.2.0]
    at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:48) ~[rxjava-1.2.0.jar:1.2.0]
    at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:30) ~[rxjava-1.2.0.jar:1.2.0]
    at rx.Observable.unsafeSubscribe(Observable.java:10151) ~[rxjava-1.2.0.jar:1.2.0]
    at rx.internal.operators.OnSubscribeDefer.call(OnSubscribeDefer.java:51) ~[rxjava-1.2.0.jar:1.2.0]
    at rx.internal.operators.OnSubscribeDefer.call(OnSubscribeDefer.java:35) ~[rxjava-1.2.0.jar:1.2.0]
    at rx.Observable.unsafeSubscribe(Observable.java:10151) ~[rxjava-1.2.0.jar:1.2.0]
    at rx.internal.operators.OnSubscribeDoOnEach.call(OnSubscribeDoOnEach.java:41) ~[rxjava-1.2.0.jar:1.2.0]
    at rx.internal.operators.OnSubscribeDoOnEach.call(OnSubscribeDoOnEach.java:30) ~[rxjava-1.2.0.jar:1.2.0]
    at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:48) ~[rxjava-1.2.0.jar:1.2.0]
    at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:30) ~[rxjava-1.2.0.jar:1.2.0]
    at rx.Observable.unsafeSubscribe(Observable.java:10151) ~[rxjava-1.2.0.jar:1.2.0]
    at rx.internal.operators.OperatorSubscribeOn$1.call(OperatorSubscribeOn.java:94) ~[rxjava-1.2.0.jar:1.2.0]
    at com.netflix.hystrix.strategy.concurrency.HystrixContexSchedulerAction$1.call(HystrixContexSchedulerAction.java:56) ~[hystrix-core-1.5.12.jar:1.5.12]
    at com.netflix.hystrix.strategy.concurrency.HystrixContexSchedulerAction$1.call(HystrixContexSchedulerAction.java:47) ~[hystrix-core-1.5.12.jar:1.5.12]
    at com.netflix.hystrix.strategy.concurrency.HystrixContexSchedulerAction.call(HystrixContexSchedulerAction.java:69) ~[hystrix-core-1.5.12.jar:1.5.12]
    at rx.internal.schedulers.ScheduledAction.run(ScheduledAction.java:55) ~[rxjava-1.2.0.jar:1.2.0]
    at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) ~[na:1.8.0_151]
    at java.util.concurrent.FutureTask.run(FutureTask.java:266) ~[na:1.8.0_151]
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) ~[na:1.8.0_151]
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) ~[na:1.8.0_151]
    at java.lang.Thread.run(Thread.java:748) [na:1.8.0_151]