Microservices JHipster microservice gateway在一个服务实例终止时临时抛出HTTP 500错误

我们有一个标准的JHipster设置，包括一个网关和一个微服务应用程序。JHipster注册表用于服务发现。我们没有对JHipster生成器生成的代码或配置进行任何更改

一切正常。但是，当关闭一个microservice应用程序实例（SIGINT、CLI上的^C、Kubernetes pod termination）时，我们会暂时收到HTTP 500内部服务器错误，这些错误是通过网关（.）向microservice端点发出的请求

请在下面找到网关中HTTP 500错误的堆栈跟踪：

Caused by: org.apache.http.NoHttpResponseException: 172.16.94.61:8085 failed to respond
    at org.apache.http.impl.conn.DefaultHttpResponseParser.parseHead(DefaultHttpResponseParser.java:141)
    at org.apache.http.impl.conn.DefaultHttpResponseParser.parseHead(DefaultHttpResponseParser.java:56)
    at org.apache.http.impl.io.AbstractMessageParser.parse(AbstractMessageParser.java:259)
    at org.apache.http.impl.DefaultBHttpClientConnection.receiveResponseHeader(DefaultBHttpClientConnection.java:163)
    at org.apache.http.impl.conn.CPoolProxy.receiveResponseHeader(CPoolProxy.java:165)
    at org.apache.http.protocol.HttpRequestExecutor.doReceiveResponse(HttpRequestExecutor.java:273)
    at org.apache.http.protocol.HttpRequestExecutor.execute(HttpRequestExecutor.java:125)
    at org.apache.http.impl.execchain.MainClientExec.execute(MainClientExec.java:272)
    at org.apache.http.impl.execchain.ProtocolExec.execute(ProtocolExec.java:185)
    at org.apache.http.impl.execchain.RetryExec.execute(RetryExec.java:89)
    at org.apache.http.impl.execchain.RedirectExec.execute(RedirectExec.java:111)
    at org.apache.http.impl.client.InternalHttpClient.doExecute(InternalHttpClient.java:185)
    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 org.springframework.cloud.netflix.ribbon.apache.RetryableRibbonLoadBalancingHttpClient$1.doWithRetry(RetryableRibbonLoadBalancingHttpClient.java:93)
    at org.springframework.cloud.netflix.ribbon.apache.RetryableRibbonLoadBalancingHttpClient$1.doWithRetry(RetryableRibbonLoadBalancingHttpClient.java:71)
    at org.springframework.retry.support.RetryTemplate.doExecute(RetryTemplate.java:287)
    at org.springframework.retry.support.RetryTemplate.execute(RetryTemplate.java:164)
    at org.springframework.cloud.netflix.ribbon.apache.RetryableRibbonLoadBalancingHttpClient.executeWithRetry(RetryableRibbonLoadBalancingHttpClient.java:113)
    at org.springframework.cloud.netflix.ribbon.apache.RetryableRibbonLoadBalancingHttpClient.execute(RetryableRibbonLoadBalancingHttpClient.java:104)
    at org.springframework.cloud.netflix.ribbon.apache.RetryableRibbonLoadBalancingHttpClient.execute(RetryableRibbonLoadBalancingHttpClient.java:50)
    at com.netflix.client.AbstractLoadBalancerAwareClient$1.call(AbstractLoadBalancerAwareClient.java:109)
    at com.netflix.loadbalancer.reactive.LoadBalancerCommand$3$1.call(LoadBalancerCommand.java:303)
    at com.netflix.loadbalancer.reactive.LoadBalancerCommand$3$1.call(LoadBalancerCommand.java:287)
    at rx.internal.util.ScalarSynchronousObservable$3.call(ScalarSynchronousObservable.java:231)
    at rx.internal.util.ScalarSynchronousObservable$3.call(ScalarSynchronousObservable.java:228)
    at rx.Observable.unsafeSubscribe(Observable.java:10211)
    at rx.internal.operators.OnSubscribeConcatMap$ConcatMapSubscriber.drain(OnSubscribeConcatMap.java:286)
    at rx.internal.operators.OnSubscribeConcatMap$ConcatMapSubscriber.onNext(OnSubscribeConcatMap.java:144)
    at com.netflix.loadbalancer.reactive.LoadBalancerCommand$1.call(LoadBalancerCommand.java:185)
    at com.netflix.loadbalancer.reactive.LoadBalancerCommand$1.call(LoadBalancerCommand.java:180)
    at rx.Observable.unsafeSubscribe(Observable.java:10211)
    at rx.internal.operators.OnSubscribeConcatMap.call(OnSubscribeConcatMap.java:94)
    at rx.internal.operators.OnSubscribeConcatMap.call(OnSubscribeConcatMap.java:42)
    at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:48)
    at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:30)
    at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:48)
    at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:30)
    at rx.Observable.subscribe(Observable.java:10307)
    at rx.Observable.subscribe(Observable.java:10274)
    at rx.observables.BlockingObservable.blockForSingle(BlockingObservable.java:445)

网关的负载平衡器似乎仍然使用正在终止的microservice实例

我们还尝试了Consor而不是JHipster Registry/Eureka，发现了同样的行为

复制步骤：

• 启动一个注册表、一个网关和两个microservice实例（使用gradlew）
• 等待并验证一切都已启动并正在运行（呼叫。）
• 终止一个微服务实例
• 关系。。。几次
  • 几秒钟后，将出现HTTP 500错误
  • 再过几秒钟，错误将消失，剩下的微服务将接收所有流量

由于我们使用的是开箱即用的JHipster设置，所以在互联网上找不到任何解决此问题的文章，这让我们感到非常困惑

有没有人经历过同样的问题，知道这里出了什么问题或者如何解决这个问题？我们花了很长时间试图找到原因和解决办法，但我们觉得我们被困在这里了

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如果您需要更多信息（日志、配置、跟踪等），我们很乐意在此处发布。

您可以通过在application.yml中设置

zuul.retryable:true

来启用

spring retry

（包含在默认JHipster网关的pom.xml中）。然后将再次尝试任何失败的GET请求。如果还希望多次尝试其他HTTP方法（如POST），请设置

ribbon.OkToRetryOnAllOperations:true

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您是否尝试过调整Eureka、Hystrix和Ribbon？超时和重试配置。设置zuul.retryable:true解决了我的问题。我还必须配置Ribbon来调整超时，现在我所有的服务请求都正常工作了。