我们在单个服务器上部署了一组微服务，这些服务隐藏在Apache之后。
在将它们分散到不同的服务器之前，我们希望确保通信安全，以便启用HTTPS。
之后发生了春天的问题。随机地一些请求失败，因为spring zuul无法将它们转发到特定的微服务（即使服务在同一服务器上）。我们得到以下例外：
com.netflix.zuul.exception.ZuulException: Forwarding error
at org.springframework.cloud.netflix.zuul.filters.route.RibbonRoutingFilter.handleException(RibbonRoutingFilter.java:188)
at org.springframework.cloud.netflix.zuul.filters.route.RibbonRoutingFilter.forward(RibbonRoutingFilter.java:163)
at org.springframework.cloud.netflix.zuul.filters.route.RibbonRoutingFilter.run(RibbonRoutingFilter.java:111)
at com.netflix.zuul.ZuulFilter.runFilter(ZuulFilter.java:112)
at com.netflix.zuul.FilterProcessor.processZuulFilter(FilterProcessor.java:193)
at com.netflix.zuul.FilterProcessor.runFilters(FilterProcessor.java:157)
at com.netflix.zuul.FilterProcessor.route(FilterProcessor.java:118)
at com.netflix.zuul.ZuulRunner.route(ZuulRunner.java:96)
at com.netflix.zuul.http.ZuulServlet.route(ZuulServlet.java:116)
at com.netflix.zuul.http.ZuulServlet.service(ZuulServlet.java:81)
at org.springframework.web.servlet.mvc.ServletWrappingController.handleRequestInternal(ServletWrappingController.java:157)
at org.springframework.cloud.netflix.zuul.web.ZuulController.handleRequest(ZuulController.java:44)
at org.springframework.web.servlet.mvc.SimpleControllerHandlerAdapter.handle(SimpleControllerHandlerAdapter.java:50)
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:967)
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:901)
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:970)
at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:872)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:661)
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:742)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.springframework.boot.web.filter.ApplicationContextHeaderFilter.doFilterInternal(ApplicationContextHeaderFilter.java:55)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.springframework.boot.actuate.trace.WebRequestTraceFilter.doFilterInternal(WebRequestTraceFilter.java:110)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:99)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.springframework.web.filter.HttpPutFormContentFilter.doFilterInternal(HttpPutFormContentFilter.java:105)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:81)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.springframework.cloud.sleuth.instrument.web.TraceFilter.doFilter(TraceFilter.java:186)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:197)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.springframework.boot.actuate.autoconfigure.MetricsFilter.doFilterInternal(MetricsFilter.java:106)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:198)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:478)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:80)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87)
at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:624)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:342)
at org.apache.coyote.ajp.AjpProcessor.service(AjpProcessor.java:486)
at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66)
at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:861)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1455)
at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Thread.java:748)
Caused by: com.netflix.hystrix.exception.HystrixRuntimeException: service-foo timed-out and no fallback available.
at com.netflix.hystrix.AbstractCommand$22.call(AbstractCommand.java:819)
at com.netflix.hystrix.AbstractCommand$22.call(AbstractCommand.java:804)
at rx.internal.operators.OperatorOnErrorResumeNextViaFunction$4.onError(OperatorOnErrorResumeNextViaFunction.java:140)
at rx.internal.operators.OnSubscribeDoOnEach$DoOnEachSubscriber.onError(OnSubscribeDoOnEach.java:87)
at rx.internal.operators.OnSubscribeDoOnEach$DoOnEachSubscriber.onError(OnSubscribeDoOnEach.java:87)
at com.netflix.hystrix.AbstractCommand$DeprecatedOnFallbackHookApplication$1.onError(AbstractCommand.java:1472)
at com.netflix.hystrix.AbstractCommand$FallbackHookApplication$1.onError(AbstractCommand.java:1397)
at rx.internal.operators.OnSubscribeDoOnEach$DoOnEachSubscriber.onError(OnSubscribeDoOnEach.java:87)
at rx.observers.Subscribers$5.onError(Subscribers.java:230)
at rx.internal.operators.OnSubscribeThrow.call(OnSubscribeThrow.java:44)
at rx.internal.operators.OnSubscribeThrow.call(OnSubscribeThrow.java:28)
at rx.Observable.unsafeSubscribe(Observable.java:10211)
at rx.internal.operators.OnSubscribeDefer.call(OnSubscribeDefer.java:51)
at rx.internal.operators.OnSubscribeDefer.call(OnSubscribeDefer.java:35)
at rx.Observable.unsafeSubscribe(Observable.java:10211)
at rx.internal.operators.OnSubscribeDoOnEach.call(OnSubscribeDoOnEach.java:41)
at rx.internal.operators.OnSubscribeDoOnEach.call(OnSubscribeDoOnEach.java:30)
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.unsafeSubscribe(Observable.java:10211)
at rx.internal.operators.OnSubscribeDoOnEach.call(OnSubscribeDoOnEach.java:41)
at rx.internal.operators.OnSubscribeDoOnEach.call(OnSubscribeDoOnEach.java:30)
at rx.Observable.unsafeSubscribe(Observable.java:10211)
at rx.internal.operators.OnSubscribeDoOnEach.call(OnSubscribeDoOnEach.java:41)
at rx.internal.operators.OnSubscribeDoOnEach.call(OnSubscribeDoOnEach.java:30)
at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:48)
at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:30)
at rx.Observable.unsafeSubscribe(Observable.java:10211)
at rx.internal.operators.OnSubscribeDoOnEach.call(OnSubscribeDoOnEach.java:41)
at rx.internal.operators.OnSubscribeDoOnEach.call(OnSubscribeDoOnEach.java:30)
at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:48)
at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:30)
at rx.Observable.unsafeSubscribe(Observable.java:10211)
at rx.internal.operators.OperatorOnErrorResumeNextViaFunction$4.onError(OperatorOnErrorResumeNextViaFunction.java:142)
at rx.internal.operators.OnSubscribeDoOnEach$DoOnEachSubscriber.onError(OnSubscribeDoOnEach.java:87)
at rx.internal.operators.OnSubscribeDoOnEach$DoOnEachSubscriber.onError(OnSubscribeDoOnEach.java:87)
at com.netflix.hystrix.AbstractCommand$HystrixObservableTimeoutOperator$1$1.run(AbstractCommand.java:1154)
at com.netflix.hystrix.strategy.concurrency.HystrixContextRunnable$1.call(HystrixContextRunnable.java:45)
at com.netflix.hystrix.strategy.concurrency.HystrixContextRunnable$1.call(HystrixContextRunnable.java:41)
at org.springframework.cloud.sleuth.instrument.hystrix.SleuthHystrixConcurrencyStrategy$HystrixTraceCallable.call(SleuthHystrixConcurrencyStrategy.java:188)
at com.netflix.hystrix.strategy.concurrency.HystrixContextRunnable.run(HystrixContextRunnable.java:61)
at com.netflix.hystrix.AbstractCommand$HystrixObservableTimeoutOperator$1.tick(AbstractCommand.java:1159)
at com.netflix.hystrix.util.HystrixTimer$1.run(HystrixTimer.java:99)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
at java.util.concurrent.FutureTask.runAndReset(FutureTask.java:308)
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$301(ScheduledThreadPoolExecutor.java:180)
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:294)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
... 1 common frames omitted
Caused by: java.util.concurrent.TimeoutException: null
at com.netflix.hystrix.AbstractCommand.handleTimeoutViaFallback(AbstractCommand.java:997)
at com.netflix.hystrix.AbstractCommand.access$500(AbstractCommand.java:60)
at com.netflix.hystrix.AbstractCommand$12.call(AbstractCommand.java:610)
at com.netflix.hystrix.AbstractCommand$12.call(AbstractCommand.java:601)
at rx.internal.operators.OperatorOnErrorResumeNextViaFunction$4.onError(OperatorOnErrorResumeNextViaFunction.java:140)
... 16 common frames omitted
几乎所有请求都通过了什么是奇怪的 - 只有一些请求失败了。
已尝试过一些解决方案，但没有帮助：
- 使用httpclient的低版本（4.4.1）
- 使用春天云的低版本（Dalston.SR2）
- 增加Apache上MaxRequestWorkers的数量
- 为连接腾出更长的时间（即使失败的zuul请求花费的时间少于3秒）： ribbon.ConnectTimeout = 3000 ribbon.ReadTimeout = 20000
所以更多的是在同一时间我打开“测试脚本”，如：
- 一直ping我的服务器
- 通过HTTPS发送请求到foo-service避免ZUUL
这两个操作都与通过ZUUL发送请求并行进行。即使在Spring Zuul失败的“时刻”，ping和直接调用foo-service也一直在工作。
当我们切换回HTTP时，它再次起作用。我看到的唯一区别是，在HTTPS的情况下，整个流量通过Apache。
我在异常之前在日志中看到的最后一件事是：
2017-11-03 12:10:45.718 DEBUG [zuul,9aceeded808781ba,9aceeded808781ba,false] 873 --- [io-8009-exec-49] h.i.c.DefaultManagedHttpClientConnection : http-outgoing-10859: Close connection
2017-11-03 12:10:45.718 DEBUG [zuul,9aceeded808781ba,9aceeded808781ba,false] 873 --- [io-8009-exec-49] o.a.http.impl.execchain.MainClientExec : Connection discarded
2017-11-03 12:10:45.718 DEBUG [zuul,9aceeded808781ba,9aceeded808781ba,false] 873 --- [io-8009-exec-49] h.i.c.PoolingHttpClientConnectionManager : Connection released: [id: 10859][route: {s}->https://my.server.com:443][total kept alive: 1; route allocated: 4 of 50; total allocated: 5 of 200]
2017-11-03 12:10:45.724 WARN [zuul,9aceeded808781ba,9aceeded808781ba,false] 873 --- [io-8009-exec-49] o.s.c.n.z.filters.post.SendErrorFilter : Error during filtering
但是我不知道我还能检查什么来找到问题的根源。
有任何想法吗？我们是否会错过应该进行的一些配置更改？
我有与你描述的完全相同的问题。基本问题是HTTPS协议较慢（尤其是在验证客户端和服务器之间的连接时）。默认情况下，Ribbon对Hystrix的超时时间为2000毫秒，而您通常为所有hystrix命令覆盖此配置的配置似乎不适用于功能区。
这是由于AbstractRibbonCommand：93中方法getSetter中的一些代码。如果检查该行，您将看到断路器的属性使用在Ribbon代码中的静态类中定义的默认值。
当启动服务连接的CircuitBreaker对象时，如果没有找到其他对象，它将使用此定义 - 类HystrixCircuitBreaker：169。我没有详细探讨为什么这里没有选择默认的Hystrix配置。
我仍然试图找出自己最好的解决方案，但zuul服务的以下属性解决了这个问题：
hystrix.command.RibbonCommand.<my-service-name>.execution.isolation.thread.timeoutInMilliseconds=5000
理想情况下，我更喜欢使用默认的hystrix超时时间，因此我很可能会添加一个Configuration类，根据配置的Zuul路由为我的所有服务实例化RibbonCommand。如果我这样做，我会更新这个答案，以便将来用于参考。
我所引用的类是Hystrix Core 1.5.12的一部分，它是Spring Cloud Edgware版本的一部分。