ZuulProxy 在应该进行故障转移时失败并显示 "RibbonCommand timed-out and no fallback available"
ZuulProxy fails with "RibbonCommand timed-out and no fallback available" when it should do failover
简短描述：
我试图让 ZuulProxy 来处理实例故障转移，但它抛出 ZuulException：转发错误，而不是使用工作实例的结果进行响应。
详细说明：
我的设置是一个独立的 Eureka Server，一个 ConfigServer，一个 ZuulProxy (@EnableZuulProxy) 和两个服务实例，它们都在 Eureka 中注册。
一切都是运行spring-cloud-starter-parent Angel.SR3
我的服务发现：
@SpringBootApplication
@EnableEurekaServer
public class EurekaServer {
public static void main(String[] args) {
SpringApplication.run(EurekaServer.class, args);
}
}
我的配置服务器：
@SpringBootApplication
@EnableAutoConfiguration
@EnableConfigServer
@ComponentScan
@EnableDiscoveryClient
public class ConfigserverApplication {
public static void main(String[] args) {
SpringApplication.run(ConfigserverApplication.class, args);
}
}
我的ZuulProxy:
@SpringBootApplication
@EnableAutoConfiguration
@ComponentScan
@EnableDiscoveryClient
@EnableZuulProxy
public class ZuulProxy {
public static void main(String[] args) {
SpringApplication.run(ZuulProxy.class, args);
}
}
zuul 中的路由规则：
zuul.ignoredServices=*
zuul.routes.examplems=/example/**
我的服务实例：
@SpringBootApplication
@Configuration
@EnableAutoConfiguration
@EnableDiscoveryClient
@ComponentScan(basePackages = "se.example.microservices")
@EnableSwagger
public class Application {
public static void main(String[] args) throws Exception{
SpringApplication.run(Application.class, args);
}
我的服务实例使用 spring.application.name=examplems
注册自己
当我启动两个服务实例并通过 zuulproxy 发送请求时，一切正常，它将请求轮询到我的两个服务实例。
但是当我停止其中一个实例时，Zuul 仍然多次尝试将请求转发到已停止的实例，然后它失败了：
com.netflix.zuul.exception.ZuulException: Forwarding error
Caused by: com.netflix.hystrix.exception.HystrixRuntimeException: examplemsRibbonCommand timed-out and no fallback available.
我原以为对已停止实例的请求会超时并透明地故障转移到 运行 实例。真正奇怪的是，zuul（根据日志）似乎首先尝试多次停止实例（这当然失败了），然后将请求转发给工作实例，得到一个 OK 的答案，而不是转发OK 对客户端的回答它抛出异常导致状态为 500 的响应失败！？
请查看日志（我的工作实例在主机 PMD11286 上，我停止的实例在 PMD11933 上）：
2015-08-20 08:45:46.343 INFO 7700 --- [nio-9050-exec-9] o.s.c.n.zuul.filters.ProxyRouteLocator : Finding route for path: /example/ping/delay
2015-08-20 08:45:46.343 DEBUG 7700 --- [nio-9050-exec-9] o.a.h.impl.conn.DefaultClientConnection : Connection 0.0.0.0:50251<->172.20.120.39:9060 closed
2015-08-20 08:45:46.343 DEBUG 7700 --- [nio-9050-exec-9] .a.h.i.c.DefaultClientConnectionOperator : Connecting to PMD11933:9060
2015-08-20 08:45:47.372 DEBUG 7700 --- [nio-9050-exec-9] .a.h.i.c.DefaultClientConnectionOperator : Connect to PMD11933:9060 timed out. Connection will be retried using another IP address
2015-08-20 08:45:47.372 DEBUG 7700 --- [nio-9050-exec-9] .a.h.i.c.DefaultClientConnectionOperator : Connecting to PMD11933:9060
2015-08-20 08:45:48.386 DEBUG 7700 --- [nio-9050-exec-9] .a.h.i.c.DefaultClientConnectionOperator : Connect to PMD11933:9060 timed out. Connection will be retried using another IP address
2015-08-20 08:45:48.386 DEBUG 7700 --- [nio-9050-exec-9] .a.h.i.c.DefaultClientConnectionOperator : Connecting to PMD11933:9060
2015-08-20 08:45:49.416 DEBUG 7700 --- [nio-9050-exec-9] .a.h.i.c.DefaultClientConnectionOperator : Connect to PMD11933:9060 timed out. Connection will be retried using another IP address
2015-08-20 08:45:49.416 DEBUG 7700 --- [nio-9050-exec-9] .a.h.i.c.DefaultClientConnectionOperator : Connecting to PMD11933:9060
2015-08-20 08:45:50.430 DEBUG 7700 --- [N_MANAGER_TIMER] o.a.h.i.c.t.ThreadSafeClientConnManager : Closing expired connections
2015-08-20 08:45:50.430 DEBUG 7700 --- [N_MANAGER_TIMER] o.a.h.impl.conn.tsccm.ConnPoolByRoute : Closing expired connections
2015-08-20 08:45:50.446 DEBUG 7700 --- [nio-9050-exec-9] .a.h.i.c.DefaultClientConnectionOperator : Connect to PMD11933:9060 timed out. Connection will be retried using another IP address
2015-08-20 08:45:50.446 DEBUG 7700 --- [nio-9050-exec-9] .a.h.i.c.DefaultClientConnectionOperator : Connecting to PMD11933:9060
2015-08-20 08:45:51.475 DEBUG 7700 --- [nio-9050-exec-9] .a.h.i.c.DefaultClientConnectionOperator : Connect to PMD11933:9060 timed out. Connection will be retried using another IP address
2015-08-20 08:45:51.475 DEBUG 7700 --- [nio-9050-exec-9] .a.h.i.c.DefaultClientConnectionOperator : Connecting to PMD11933:9060
2015-08-20 08:45:52.505 DEBUG 7700 --- [nio-9050-exec-9] o.a.h.impl.conn.DefaultClientConnection : Connection 0.0.0.0:50251<->172.20.120.39:9060 closed
2015-08-20 08:45:52.505 DEBUG 7700 --- [nio-9050-exec-9] o.a.h.impl.conn.DefaultClientConnection : Connection 0.0.0.0:50251<->172.20.120.39:9060 shut down
2015-08-20 08:45:52.505 DEBUG 7700 --- [nio-9050-exec-9] o.a.h.impl.conn.DefaultClientConnection : Connection 0.0.0.0:50251<->172.20.120.39:9060 closed
2015-08-20 08:45:52.520 DEBUG 7700 --- [nio-9050-exec-9] o.a.h.client.protocol.RequestAddCookies : CookieSpec selected: ignoreCookies
2015-08-20 08:45:52.520 DEBUG 7700 --- [nio-9050-exec-9] o.a.h.client.protocol.RequestAuthCache : Auth cache not set in the context
2015-08-20 08:45:52.520 DEBUG 7700 --- [nio-9050-exec-9] o.a.h.c.p.RequestTargetAuthentication : Target auth state: UNCHALLENGED
2015-08-20 08:45:52.520 DEBUG 7700 --- [nio-9050-exec-9] o.a.h.c.p.RequestProxyAuthentication : Proxy auth state: UNCHALLENGED
2015-08-20 08:45:52.520 DEBUG 7700 --- [nio-9050-exec-9] o.a.h.impl.conn.DefaultClientConnection : Sending request: GET /ping/delay HTTP/1.1
2015-08-20 08:45:52.520 DEBUG 7700 --- [nio-9050-exec-9] org.apache.http.wire : >> "GET /ping/delay HTTP/1.1[\r][\n]"
2015-08-20 08:45:52.520 DEBUG 7700 --- [nio-9050-exec-9] org.apache.http.wire : >> "x-forwarded-host: 127.0.0.1:9050[\r][\n]"
2015-08-20 08:45:52.520 DEBUG 7700 --- [nio-9050-exec-9] org.apache.http.wire : >> "x-forwarded-prefix: /example[\r][\n]"
2015-08-20 08:45:52.520 DEBUG 7700 --- [nio-9050-exec-9] org.apache.http.wire : >> "accept-encoding: deflate, gzip[\r][\n]"
2015-08-20 08:45:52.520 DEBUG 7700 --- [nio-9050-exec-9] org.apache.http.wire : >> "user-agent: curl/7.42.1[\r][\n]"
2015-08-20 08:45:52.520 DEBUG 7700 --- [nio-9050-exec-9] org.apache.http.wire : >> "accept: */*[\r][\n]"
2015-08-20 08:45:52.520 DEBUG 7700 --- [nio-9050-exec-9] org.apache.http.wire : >> "Netflix.NFHttpClient.Version: 1.0[\r][\n]"
2015-08-20 08:45:52.520 DEBUG 7700 --- [nio-9050-exec-9] org.apache.http.wire : >> "X-netflix-httpclientname: examplems[\r][\n]"
2015-08-20 08:45:52.520 DEBUG 7700 --- [nio-9050-exec-9] org.apache.http.wire : >> "Host: PMD11286:9060[\r][\n]"
2015-08-20 08:45:52.520 DEBUG 7700 --- [nio-9050-exec-9] org.apache.http.wire : >> "Connection: Keep-Alive[\r][\n]"
2015-08-20 08:45:52.520 DEBUG 7700 --- [nio-9050-exec-9] org.apache.http.wire : >> "[\r][\n]"
2015-08-20 08:45:52.520 DEBUG 7700 --- [nio-9050-exec-9] org.apache.http.headers : >> GET /ping/delay HTTP/1.1
2015-08-20 08:45:52.520 DEBUG 7700 --- [nio-9050-exec-9] org.apache.http.headers : >> x-forwarded-host: 127.0.0.1:9050
2015-08-20 08:45:52.520 DEBUG 7700 --- [nio-9050-exec-9] org.apache.http.headers : >> x-forwarded-prefix: /example
2015-08-20 08:45:52.520 DEBUG 7700 --- [nio-9050-exec-9] org.apache.http.headers : >> accept-encoding: deflate, gzip
2015-08-20 08:45:52.520 DEBUG 7700 --- [nio-9050-exec-9] org.apache.http.headers : >> user-agent: curl/7.42.1
2015-08-20 08:45:52.520 DEBUG 7700 --- [nio-9050-exec-9] org.apache.http.headers : >> accept: */*
2015-08-20 08:45:52.520 DEBUG 7700 --- [nio-9050-exec-9] org.apache.http.headers : >> Netflix.NFHttpClient.Version: 1.0
2015-08-20 08:45:52.520 DEBUG 7700 --- [nio-9050-exec-9] org.apache.http.headers : >> X-netflix-httpclientname: examplems
2015-08-20 08:45:52.520 DEBUG 7700 --- [nio-9050-exec-9] org.apache.http.headers : >> Host: PMD11286:9060
2015-08-20 08:45:52.520 DEBUG 7700 --- [nio-9050-exec-9] org.apache.http.headers : >> Connection: Keep-Alive
2015-08-20 08:45:52.630 DEBUG 7700 --- [nio-9050-exec-9] org.apache.http.wire : << "HTTP/1.1 200 OK[\r][\n]"
2015-08-20 08:45:52.630 DEBUG 7700 --- [nio-9050-exec-9] org.apache.http.wire : << "Server: Apache-Coyote/1.1[\r][\n]"
2015-08-20 08:45:52.630 DEBUG 7700 --- [nio-9050-exec-9] org.apache.http.wire : << "X-Application-Context: examplems:9060[\r][\n]"
2015-08-20 08:45:52.630 DEBUG 7700 --- [nio-9050-exec-9] org.apache.http.wire : << "Content-Type: text/plain;charset=UTF-8[\r][\n]"
2015-08-20 08:45:52.630 DEBUG 7700 --- [nio-9050-exec-9] org.apache.http.wire : << "Content-Length: 76[\r][\n]"
2015-08-20 08:45:52.630 DEBUG 7700 --- [nio-9050-exec-9] org.apache.http.wire : << "Date: Thu, 20 Aug 2015 06:45:52 GMT[\r][\n]"
2015-08-20 08:45:52.630 DEBUG 7700 --- [nio-9050-exec-9] org.apache.http.wire : << "[\r][\n]"
2015-08-20 08:45:52.630 DEBUG 7700 --- [nio-9050-exec-9] o.a.h.impl.conn.DefaultClientConnection : Receiving response: HTTP/1.1 200 OK
2015-08-20 08:45:52.630 DEBUG 7700 --- [nio-9050-exec-9] org.apache.http.headers : << HTTP/1.1 200 OK
2015-08-20 08:45:52.630 DEBUG 7700 --- [nio-9050-exec-9] org.apache.http.headers : << Server: Apache-Coyote/1.1
2015-08-20 08:45:52.630 DEBUG 7700 --- [nio-9050-exec-9] org.apache.http.headers : << X-Application-Context: examplems:9060
2015-08-20 08:45:52.630 DEBUG 7700 --- [nio-9050-exec-9] org.apache.http.headers : << Content-Type: text/plain;charset=UTF-8
2015-08-20 08:45:52.630 DEBUG 7700 --- [nio-9050-exec-9] org.apache.http.headers : << Content-Length: 76
2015-08-20 08:45:52.630 DEBUG 7700 --- [nio-9050-exec-9] org.apache.http.headers : << Date: Thu, 20 Aug 2015 06:45:52 GMT
2015-08-20 08:45:52.630 DEBUG 7700 --- [nio-9050-exec-9] org.apache.http.wire : << "Svar efter 100 ms v[0xc3][0xa4]ntan. Kan [0xc3][0xa4]ndras med: ?time=200 15-08-20 08:45:52,618"
2015-08-20 08:45:52.630 WARN 7700 --- [nio-9050-exec-9] o.s.c.n.z.filters.post.SendErrorFilter : Error during filtering
com.netflix.zuul.exception.ZuulException: Forwarding error
at org.springframework.cloud.netflix.zuul.filters.route.RibbonRoutingFilter.forward(RibbonRoutingFilter.java:142)
at org.springframework.cloud.netflix.zuul.filters.route.RibbonRoutingFilter.run(RibbonRoutingFilter.java:107)
at com.netflix.zuul.ZuulFilter.runFilter(ZuulFilter.java:112)
at com.netflix.zuul.FilterProcessor.processZuulFilter(FilterProcessor.java:197)
at com.netflix.zuul.FilterProcessor.runFilters(FilterProcessor.java:161)
at com.netflix.zuul.FilterProcessor.route(FilterProcessor.java:120)
at com.netflix.zuul.ZuulRunner.route(ZuulRunner.java:84)
at com.netflix.zuul.http.ZuulServlet.route(ZuulServlet.java:111)
at com.netflix.zuul.http.ZuulServlet.service(ZuulServlet.java:77)
at org.springframework.web.servlet.mvc.ServletWrappingController.handleRequestInternal(ServletWrappingController.java:158)
at org.springframework.cloud.netflix.zuul.web.ZuulController.handleRequestInternal(ZuulController.java:43)
at org.springframework.web.servlet.mvc.AbstractController.handleRequest(AbstractController.java:146)
at org.springframework.web.servlet.mvc.SimpleControllerHandlerAdapter.handle(SimpleControllerHandlerAdapter.java:50)
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:959)
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:893)
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:966)
at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:857)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:618)
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:842)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:725)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:291)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.springframework.boot.actuate.autoconfigure.EndpointWebMvcAutoConfiguration$ApplicationContextHeaderFilter.doFilterInternal(EndpointWebMvcAutoConfiguration.java:291)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:77)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.springframework.boot.actuate.trace.WebRequestTraceFilter.doFilterInternal(WebRequestTraceFilter.java:102)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:85)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.springframework.boot.actuate.autoconfigure.MetricFilterAutoConfiguration$MetricsFilter.doFilterInternal(MetricFilterAutoConfiguration.java:90)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:219)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:106)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:501)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:142)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:516)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1086)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:659)
at org.apache.coyote.http11.Http11NioProtocol$Http11ConnectionHandler.process(Http11NioProtocol.java:223)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1558)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1515)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Thread.java:745)
Caused by: com.netflix.hystrix.exception.HystrixRuntimeException: examplemsRibbonCommand timed-out and no fallback available.
at com.netflix.hystrix.AbstractCommand.call(AbstractCommand.java:782)
at com.netflix.hystrix.AbstractCommand.call(AbstractCommand.java:769)
at rx.internal.operators.OperatorOnErrorResumeNextViaFunction.onError(OperatorOnErrorResumeNextViaFunction.java:77)
at rx.internal.operators.OperatorDoOnEach.onError(OperatorDoOnEach.java:70)
at rx.internal.operators.OperatorDoOnEach.onError(OperatorDoOnEach.java:70)
at rx.internal.operators.OperatorDoOnEach.onError(OperatorDoOnEach.java:70)
at com.netflix.hystrix.AbstractCommand$DeprecatedOnFallbackHookApplication.onError(AbstractCommand.java:1444)
at com.netflix.hystrix.AbstractCommand$FallbackHookApplication.onError(AbstractCommand.java:1334)
at com.netflix.hystrix.HystrixCommand.call(HystrixCommand.java:314)
at com.netflix.hystrix.HystrixCommand.call(HystrixCommand.java:306)
at rx.Observable.call(Observable.java:144)
at rx.Observable.call(Observable.java:136)
at rx.Observable.call(Observable.java:144)
at rx.Observable.call(Observable.java:136)
at rx.Observable.call(Observable.java:144)
at rx.Observable.call(Observable.java:136)
at rx.Observable.call(Observable.java:144)
at rx.Observable.call(Observable.java:136)
at rx.Observable.call(Observable.java:144)
at rx.Observable.call(Observable.java:136)
at rx.Observable.call(Observable.java:144)
at rx.Observable.call(Observable.java:136)
at rx.Observable.call(Observable.java:144)
at rx.Observable.call(Observable.java:136)
at rx.Observable.call(Observable.java:144)
at rx.Observable.call(Observable.java:136)
at rx.Observable.call(Observable.java:144)
at rx.Observable.call(Observable.java:136)
at rx.Observable.call(Observable.java:144)
at rx.Observable.call(Observable.java:136)
at rx.Observable.unsafeSubscribe(Observable.java:7466)
at rx.internal.operators.OperatorOnErrorResumeNextViaFunction.onError(OperatorOnErrorResumeNextViaFunction.java:78)
at rx.internal.operators.OperatorDoOnEach.onError(OperatorDoOnEach.java:70)
at rx.internal.operators.OperatorDoOnEach.onError(OperatorDoOnEach.java:70)
at com.netflix.hystrix.AbstractCommand$HystrixObservableTimeoutOperator.run(AbstractCommand.java:923)
at com.netflix.hystrix.strategy.concurrency.HystrixContextRunnable.call(HystrixContextRunnable.java:41)
at com.netflix.hystrix.strategy.concurrency.HystrixContextRunnable.call(HystrixContextRunnable.java:37)
at com.netflix.hystrix.strategy.concurrency.HystrixContextRunnable.run(HystrixContextRunnable.java:57)
at com.netflix.hystrix.AbstractCommand$HystrixObservableTimeoutOperator.tick(AbstractCommand.java:943)
at com.netflix.hystrix.util.HystrixTimer.run(HystrixTimer.java:98)
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.access1(ScheduledThreadPoolExecutor.java:180)
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:294)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
... 1 common frames omitted
Caused by: java.util.concurrent.TimeoutException: null
at com.netflix.hystrix.AbstractCommand.call(AbstractCommand.java:589)
at com.netflix.hystrix.AbstractCommand.call(AbstractCommand.java:570)
at rx.internal.operators.OperatorOnErrorResumeNextViaFunction.onError(OperatorOnErrorResumeNextViaFunction.java:77)
... 15 common frames omitted
如果我等一两分钟，服务将从 eureka 中删除，并最终传播到 zuulproxy，这意味着不再有流量流向已停止的服务。但我的假设是 ribbon/hysterix 会更多地处理无响应服务 elegant/rapidly。
有hint/suggestion吗？
感谢马格纳斯
1/超时
Zuul 请求由 Hystrix 监控，其目的（在该应用程序中）是对长 运行 请求应用超时。
Hystrix 提供了两种不同的方式来执行命令和强制超时：SEMAPHORE 和 THREAD 执行隔离。
当使用 THREAD 隔离时，Hystrix 命令在线程池中的单独线程上执行。 Hystrix 然后 "pauses" 线程持有传入的请求，直到从下游服务器收到响应或发生超时。
当使用SEMAPHORE隔离时，Hystrix命令在请求线程上执行。只有在从下游服务器收到响应后才会检测到超时。因此，如果您将 Zuul/Hystrix 配置为超时 5 秒，而您的服务需要 30 秒才能完成，您的客户端将仅在 30 秒后收到超时通知 - 即使服务响应成功 (!)
Netflix 建议默认执行 THREAD，少数情况除外。不幸的是，出于我不知道的原因，SpringCloud Zuul 集成将其更改为 SEMAPHORE。有关详细信息，请参阅 Why is ZUUL forcing a SEMAPHORE isolation to execute its Hystrix commands?。
这解释了为什么您收到 500 错误，尽管已成功联系剩余的实时服务器。
2/重试
功能区用于对远程服务进行实际调用。它使用 Eureka 提供的信息来确定可用的服务和相应的地址。 Eureka 使用每 30 秒更新一次的本地缓存。所以正如@spencergibb 所说，它可能会保留过时的信息一段时间（死服务器）——但这是预料之中的。
功能区在 connect/contact 服务失败时自动重试。它可以配置为在尝试另一个服务器之前重试同一台服务器几次。我不记得默认值和实际配置 属性，但我个人一直在使用以下设置：
# Max number of retries on the same server (excluding the first try)
ribbon.maxAutoRetries = 1
# Max number of next servers to retry (excluding the first server)
ribbon.MaxAutoRetriesNextServer = 2
3/ 连接超时
从您的日志看来，尝试连接到远程服务大约需要 1 秒才能失败。这对于停止服务来说非常长。尝试连接到没有服务侦听的 TCP 端口应该立即失败（至少如果 host/ip 是可访问的并且连接尝试不会在无效中结束）...
连接超时由以下内容控制 属性 - 确保将其设置为下降值：
# Connect timeout used by Apache HttpClient
ribbon.ConnectTimeout=3000
# Read timeout used by Apache HttpClient
ribbon.ReadTimeout=5000
希望这些信息能帮助您解决问题 ;-)
简短描述： 我试图让 ZuulProxy 来处理实例故障转移，但它抛出 ZuulException：转发错误，而不是使用工作实例的结果进行响应。
详细说明： 我的设置是一个独立的 Eureka Server，一个 ConfigServer，一个 ZuulProxy (@EnableZuulProxy) 和两个服务实例，它们都在 Eureka 中注册。
一切都是运行spring-cloud-starter-parent Angel.SR3
我的服务发现：
@SpringBootApplication
@EnableEurekaServer
public class EurekaServer {
public static void main(String[] args) {
SpringApplication.run(EurekaServer.class, args);
}
}
我的配置服务器：
@SpringBootApplication
@EnableAutoConfiguration
@EnableConfigServer
@ComponentScan
@EnableDiscoveryClient
public class ConfigserverApplication {
public static void main(String[] args) {
SpringApplication.run(ConfigserverApplication.class, args);
}
}
我的ZuulProxy:
@SpringBootApplication
@EnableAutoConfiguration
@ComponentScan
@EnableDiscoveryClient
@EnableZuulProxy
public class ZuulProxy {
public static void main(String[] args) {
SpringApplication.run(ZuulProxy.class, args);
}
}
zuul 中的路由规则：
zuul.ignoredServices=*
zuul.routes.examplems=/example/**
我的服务实例：
@SpringBootApplication
@Configuration
@EnableAutoConfiguration
@EnableDiscoveryClient
@ComponentScan(basePackages = "se.example.microservices")
@EnableSwagger
public class Application {
public static void main(String[] args) throws Exception{
SpringApplication.run(Application.class, args);
}
我的服务实例使用 spring.application.name=examplems
当我启动两个服务实例并通过 zuulproxy 发送请求时，一切正常，它将请求轮询到我的两个服务实例。 但是当我停止其中一个实例时，Zuul 仍然多次尝试将请求转发到已停止的实例，然后它失败了：
com.netflix.zuul.exception.ZuulException: Forwarding error
Caused by: com.netflix.hystrix.exception.HystrixRuntimeException: examplemsRibbonCommand timed-out and no fallback available.
我原以为对已停止实例的请求会超时并透明地故障转移到 运行 实例。真正奇怪的是，zuul（根据日志）似乎首先尝试多次停止实例（这当然失败了），然后将请求转发给工作实例，得到一个 OK 的答案，而不是转发OK 对客户端的回答它抛出异常导致状态为 500 的响应失败！？
请查看日志（我的工作实例在主机 PMD11286 上，我停止的实例在 PMD11933 上）：
2015-08-20 08:45:46.343 INFO 7700 --- [nio-9050-exec-9] o.s.c.n.zuul.filters.ProxyRouteLocator : Finding route for path: /example/ping/delay
2015-08-20 08:45:46.343 DEBUG 7700 --- [nio-9050-exec-9] o.a.h.impl.conn.DefaultClientConnection : Connection 0.0.0.0:50251<->172.20.120.39:9060 closed
2015-08-20 08:45:46.343 DEBUG 7700 --- [nio-9050-exec-9] .a.h.i.c.DefaultClientConnectionOperator : Connecting to PMD11933:9060
2015-08-20 08:45:47.372 DEBUG 7700 --- [nio-9050-exec-9] .a.h.i.c.DefaultClientConnectionOperator : Connect to PMD11933:9060 timed out. Connection will be retried using another IP address
2015-08-20 08:45:47.372 DEBUG 7700 --- [nio-9050-exec-9] .a.h.i.c.DefaultClientConnectionOperator : Connecting to PMD11933:9060
2015-08-20 08:45:48.386 DEBUG 7700 --- [nio-9050-exec-9] .a.h.i.c.DefaultClientConnectionOperator : Connect to PMD11933:9060 timed out. Connection will be retried using another IP address
2015-08-20 08:45:48.386 DEBUG 7700 --- [nio-9050-exec-9] .a.h.i.c.DefaultClientConnectionOperator : Connecting to PMD11933:9060
2015-08-20 08:45:49.416 DEBUG 7700 --- [nio-9050-exec-9] .a.h.i.c.DefaultClientConnectionOperator : Connect to PMD11933:9060 timed out. Connection will be retried using another IP address
2015-08-20 08:45:49.416 DEBUG 7700 --- [nio-9050-exec-9] .a.h.i.c.DefaultClientConnectionOperator : Connecting to PMD11933:9060
2015-08-20 08:45:50.430 DEBUG 7700 --- [N_MANAGER_TIMER] o.a.h.i.c.t.ThreadSafeClientConnManager : Closing expired connections
2015-08-20 08:45:50.430 DEBUG 7700 --- [N_MANAGER_TIMER] o.a.h.impl.conn.tsccm.ConnPoolByRoute : Closing expired connections
2015-08-20 08:45:50.446 DEBUG 7700 --- [nio-9050-exec-9] .a.h.i.c.DefaultClientConnectionOperator : Connect to PMD11933:9060 timed out. Connection will be retried using another IP address
2015-08-20 08:45:50.446 DEBUG 7700 --- [nio-9050-exec-9] .a.h.i.c.DefaultClientConnectionOperator : Connecting to PMD11933:9060
2015-08-20 08:45:51.475 DEBUG 7700 --- [nio-9050-exec-9] .a.h.i.c.DefaultClientConnectionOperator : Connect to PMD11933:9060 timed out. Connection will be retried using another IP address
2015-08-20 08:45:51.475 DEBUG 7700 --- [nio-9050-exec-9] .a.h.i.c.DefaultClientConnectionOperator : Connecting to PMD11933:9060
2015-08-20 08:45:52.505 DEBUG 7700 --- [nio-9050-exec-9] o.a.h.impl.conn.DefaultClientConnection : Connection 0.0.0.0:50251<->172.20.120.39:9060 closed
2015-08-20 08:45:52.505 DEBUG 7700 --- [nio-9050-exec-9] o.a.h.impl.conn.DefaultClientConnection : Connection 0.0.0.0:50251<->172.20.120.39:9060 shut down
2015-08-20 08:45:52.505 DEBUG 7700 --- [nio-9050-exec-9] o.a.h.impl.conn.DefaultClientConnection : Connection 0.0.0.0:50251<->172.20.120.39:9060 closed
2015-08-20 08:45:52.520 DEBUG 7700 --- [nio-9050-exec-9] o.a.h.client.protocol.RequestAddCookies : CookieSpec selected: ignoreCookies
2015-08-20 08:45:52.520 DEBUG 7700 --- [nio-9050-exec-9] o.a.h.client.protocol.RequestAuthCache : Auth cache not set in the context
2015-08-20 08:45:52.520 DEBUG 7700 --- [nio-9050-exec-9] o.a.h.c.p.RequestTargetAuthentication : Target auth state: UNCHALLENGED
2015-08-20 08:45:52.520 DEBUG 7700 --- [nio-9050-exec-9] o.a.h.c.p.RequestProxyAuthentication : Proxy auth state: UNCHALLENGED
2015-08-20 08:45:52.520 DEBUG 7700 --- [nio-9050-exec-9] o.a.h.impl.conn.DefaultClientConnection : Sending request: GET /ping/delay HTTP/1.1
2015-08-20 08:45:52.520 DEBUG 7700 --- [nio-9050-exec-9] org.apache.http.wire : >> "GET /ping/delay HTTP/1.1[\r][\n]"
2015-08-20 08:45:52.520 DEBUG 7700 --- [nio-9050-exec-9] org.apache.http.wire : >> "x-forwarded-host: 127.0.0.1:9050[\r][\n]"
2015-08-20 08:45:52.520 DEBUG 7700 --- [nio-9050-exec-9] org.apache.http.wire : >> "x-forwarded-prefix: /example[\r][\n]"
2015-08-20 08:45:52.520 DEBUG 7700 --- [nio-9050-exec-9] org.apache.http.wire : >> "accept-encoding: deflate, gzip[\r][\n]"
2015-08-20 08:45:52.520 DEBUG 7700 --- [nio-9050-exec-9] org.apache.http.wire : >> "user-agent: curl/7.42.1[\r][\n]"
2015-08-20 08:45:52.520 DEBUG 7700 --- [nio-9050-exec-9] org.apache.http.wire : >> "accept: */*[\r][\n]"
2015-08-20 08:45:52.520 DEBUG 7700 --- [nio-9050-exec-9] org.apache.http.wire : >> "Netflix.NFHttpClient.Version: 1.0[\r][\n]"
2015-08-20 08:45:52.520 DEBUG 7700 --- [nio-9050-exec-9] org.apache.http.wire : >> "X-netflix-httpclientname: examplems[\r][\n]"
2015-08-20 08:45:52.520 DEBUG 7700 --- [nio-9050-exec-9] org.apache.http.wire : >> "Host: PMD11286:9060[\r][\n]"
2015-08-20 08:45:52.520 DEBUG 7700 --- [nio-9050-exec-9] org.apache.http.wire : >> "Connection: Keep-Alive[\r][\n]"
2015-08-20 08:45:52.520 DEBUG 7700 --- [nio-9050-exec-9] org.apache.http.wire : >> "[\r][\n]"
2015-08-20 08:45:52.520 DEBUG 7700 --- [nio-9050-exec-9] org.apache.http.headers : >> GET /ping/delay HTTP/1.1
2015-08-20 08:45:52.520 DEBUG 7700 --- [nio-9050-exec-9] org.apache.http.headers : >> x-forwarded-host: 127.0.0.1:9050
2015-08-20 08:45:52.520 DEBUG 7700 --- [nio-9050-exec-9] org.apache.http.headers : >> x-forwarded-prefix: /example
2015-08-20 08:45:52.520 DEBUG 7700 --- [nio-9050-exec-9] org.apache.http.headers : >> accept-encoding: deflate, gzip
2015-08-20 08:45:52.520 DEBUG 7700 --- [nio-9050-exec-9] org.apache.http.headers : >> user-agent: curl/7.42.1
2015-08-20 08:45:52.520 DEBUG 7700 --- [nio-9050-exec-9] org.apache.http.headers : >> accept: */*
2015-08-20 08:45:52.520 DEBUG 7700 --- [nio-9050-exec-9] org.apache.http.headers : >> Netflix.NFHttpClient.Version: 1.0
2015-08-20 08:45:52.520 DEBUG 7700 --- [nio-9050-exec-9] org.apache.http.headers : >> X-netflix-httpclientname: examplems
2015-08-20 08:45:52.520 DEBUG 7700 --- [nio-9050-exec-9] org.apache.http.headers : >> Host: PMD11286:9060
2015-08-20 08:45:52.520 DEBUG 7700 --- [nio-9050-exec-9] org.apache.http.headers : >> Connection: Keep-Alive
2015-08-20 08:45:52.630 DEBUG 7700 --- [nio-9050-exec-9] org.apache.http.wire : << "HTTP/1.1 200 OK[\r][\n]"
2015-08-20 08:45:52.630 DEBUG 7700 --- [nio-9050-exec-9] org.apache.http.wire : << "Server: Apache-Coyote/1.1[\r][\n]"
2015-08-20 08:45:52.630 DEBUG 7700 --- [nio-9050-exec-9] org.apache.http.wire : << "X-Application-Context: examplems:9060[\r][\n]"
2015-08-20 08:45:52.630 DEBUG 7700 --- [nio-9050-exec-9] org.apache.http.wire : << "Content-Type: text/plain;charset=UTF-8[\r][\n]"
2015-08-20 08:45:52.630 DEBUG 7700 --- [nio-9050-exec-9] org.apache.http.wire : << "Content-Length: 76[\r][\n]"
2015-08-20 08:45:52.630 DEBUG 7700 --- [nio-9050-exec-9] org.apache.http.wire : << "Date: Thu, 20 Aug 2015 06:45:52 GMT[\r][\n]"
2015-08-20 08:45:52.630 DEBUG 7700 --- [nio-9050-exec-9] org.apache.http.wire : << "[\r][\n]"
2015-08-20 08:45:52.630 DEBUG 7700 --- [nio-9050-exec-9] o.a.h.impl.conn.DefaultClientConnection : Receiving response: HTTP/1.1 200 OK
2015-08-20 08:45:52.630 DEBUG 7700 --- [nio-9050-exec-9] org.apache.http.headers : << HTTP/1.1 200 OK
2015-08-20 08:45:52.630 DEBUG 7700 --- [nio-9050-exec-9] org.apache.http.headers : << Server: Apache-Coyote/1.1
2015-08-20 08:45:52.630 DEBUG 7700 --- [nio-9050-exec-9] org.apache.http.headers : << X-Application-Context: examplems:9060
2015-08-20 08:45:52.630 DEBUG 7700 --- [nio-9050-exec-9] org.apache.http.headers : << Content-Type: text/plain;charset=UTF-8
2015-08-20 08:45:52.630 DEBUG 7700 --- [nio-9050-exec-9] org.apache.http.headers : << Content-Length: 76
2015-08-20 08:45:52.630 DEBUG 7700 --- [nio-9050-exec-9] org.apache.http.headers : << Date: Thu, 20 Aug 2015 06:45:52 GMT
2015-08-20 08:45:52.630 DEBUG 7700 --- [nio-9050-exec-9] org.apache.http.wire : << "Svar efter 100 ms v[0xc3][0xa4]ntan. Kan [0xc3][0xa4]ndras med: ?time=200 15-08-20 08:45:52,618"
2015-08-20 08:45:52.630 WARN 7700 --- [nio-9050-exec-9] o.s.c.n.z.filters.post.SendErrorFilter : Error during filtering
com.netflix.zuul.exception.ZuulException: Forwarding error
at org.springframework.cloud.netflix.zuul.filters.route.RibbonRoutingFilter.forward(RibbonRoutingFilter.java:142)
at org.springframework.cloud.netflix.zuul.filters.route.RibbonRoutingFilter.run(RibbonRoutingFilter.java:107)
at com.netflix.zuul.ZuulFilter.runFilter(ZuulFilter.java:112)
at com.netflix.zuul.FilterProcessor.processZuulFilter(FilterProcessor.java:197)
at com.netflix.zuul.FilterProcessor.runFilters(FilterProcessor.java:161)
at com.netflix.zuul.FilterProcessor.route(FilterProcessor.java:120)
at com.netflix.zuul.ZuulRunner.route(ZuulRunner.java:84)
at com.netflix.zuul.http.ZuulServlet.route(ZuulServlet.java:111)
at com.netflix.zuul.http.ZuulServlet.service(ZuulServlet.java:77)
at org.springframework.web.servlet.mvc.ServletWrappingController.handleRequestInternal(ServletWrappingController.java:158)
at org.springframework.cloud.netflix.zuul.web.ZuulController.handleRequestInternal(ZuulController.java:43)
at org.springframework.web.servlet.mvc.AbstractController.handleRequest(AbstractController.java:146)
at org.springframework.web.servlet.mvc.SimpleControllerHandlerAdapter.handle(SimpleControllerHandlerAdapter.java:50)
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:959)
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:893)
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:966)
at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:857)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:618)
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:842)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:725)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:291)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.springframework.boot.actuate.autoconfigure.EndpointWebMvcAutoConfiguration$ApplicationContextHeaderFilter.doFilterInternal(EndpointWebMvcAutoConfiguration.java:291)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:77)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.springframework.boot.actuate.trace.WebRequestTraceFilter.doFilterInternal(WebRequestTraceFilter.java:102)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:85)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.springframework.boot.actuate.autoconfigure.MetricFilterAutoConfiguration$MetricsFilter.doFilterInternal(MetricFilterAutoConfiguration.java:90)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:219)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:106)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:501)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:142)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:516)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1086)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:659)
at org.apache.coyote.http11.Http11NioProtocol$Http11ConnectionHandler.process(Http11NioProtocol.java:223)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1558)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1515)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Thread.java:745)
Caused by: com.netflix.hystrix.exception.HystrixRuntimeException: examplemsRibbonCommand timed-out and no fallback available.
at com.netflix.hystrix.AbstractCommand.call(AbstractCommand.java:782)
at com.netflix.hystrix.AbstractCommand.call(AbstractCommand.java:769)
at rx.internal.operators.OperatorOnErrorResumeNextViaFunction.onError(OperatorOnErrorResumeNextViaFunction.java:77)
at rx.internal.operators.OperatorDoOnEach.onError(OperatorDoOnEach.java:70)
at rx.internal.operators.OperatorDoOnEach.onError(OperatorDoOnEach.java:70)
at rx.internal.operators.OperatorDoOnEach.onError(OperatorDoOnEach.java:70)
at com.netflix.hystrix.AbstractCommand$DeprecatedOnFallbackHookApplication.onError(AbstractCommand.java:1444)
at com.netflix.hystrix.AbstractCommand$FallbackHookApplication.onError(AbstractCommand.java:1334)
at com.netflix.hystrix.HystrixCommand.call(HystrixCommand.java:314)
at com.netflix.hystrix.HystrixCommand.call(HystrixCommand.java:306)
at rx.Observable.call(Observable.java:144)
at rx.Observable.call(Observable.java:136)
at rx.Observable.call(Observable.java:144)
at rx.Observable.call(Observable.java:136)
at rx.Observable.call(Observable.java:144)
at rx.Observable.call(Observable.java:136)
at rx.Observable.call(Observable.java:144)
at rx.Observable.call(Observable.java:136)
at rx.Observable.call(Observable.java:144)
at rx.Observable.call(Observable.java:136)
at rx.Observable.call(Observable.java:144)
at rx.Observable.call(Observable.java:136)
at rx.Observable.call(Observable.java:144)
at rx.Observable.call(Observable.java:136)
at rx.Observable.call(Observable.java:144)
at rx.Observable.call(Observable.java:136)
at rx.Observable.call(Observable.java:144)
at rx.Observable.call(Observable.java:136)
at rx.Observable.call(Observable.java:144)
at rx.Observable.call(Observable.java:136)
at rx.Observable.unsafeSubscribe(Observable.java:7466)
at rx.internal.operators.OperatorOnErrorResumeNextViaFunction.onError(OperatorOnErrorResumeNextViaFunction.java:78)
at rx.internal.operators.OperatorDoOnEach.onError(OperatorDoOnEach.java:70)
at rx.internal.operators.OperatorDoOnEach.onError(OperatorDoOnEach.java:70)
at com.netflix.hystrix.AbstractCommand$HystrixObservableTimeoutOperator.run(AbstractCommand.java:923)
at com.netflix.hystrix.strategy.concurrency.HystrixContextRunnable.call(HystrixContextRunnable.java:41)
at com.netflix.hystrix.strategy.concurrency.HystrixContextRunnable.call(HystrixContextRunnable.java:37)
at com.netflix.hystrix.strategy.concurrency.HystrixContextRunnable.run(HystrixContextRunnable.java:57)
at com.netflix.hystrix.AbstractCommand$HystrixObservableTimeoutOperator.tick(AbstractCommand.java:943)
at com.netflix.hystrix.util.HystrixTimer.run(HystrixTimer.java:98)
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.access1(ScheduledThreadPoolExecutor.java:180)
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:294)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
... 1 common frames omitted
Caused by: java.util.concurrent.TimeoutException: null
at com.netflix.hystrix.AbstractCommand.call(AbstractCommand.java:589)
at com.netflix.hystrix.AbstractCommand.call(AbstractCommand.java:570)
at rx.internal.operators.OperatorOnErrorResumeNextViaFunction.onError(OperatorOnErrorResumeNextViaFunction.java:77)
... 15 common frames omitted
如果我等一两分钟，服务将从 eureka 中删除，并最终传播到 zuulproxy，这意味着不再有流量流向已停止的服务。但我的假设是 ribbon/hysterix 会更多地处理无响应服务 elegant/rapidly。
有hint/suggestion吗？ 感谢马格纳斯
1/超时
Zuul 请求由 Hystrix 监控，其目的（在该应用程序中）是对长 运行 请求应用超时。
Hystrix 提供了两种不同的方式来执行命令和强制超时：SEMAPHORE 和 THREAD 执行隔离。
当使用 THREAD 隔离时，Hystrix 命令在线程池中的单独线程上执行。 Hystrix 然后 "pauses" 线程持有传入的请求，直到从下游服务器收到响应或发生超时。
当使用SEMAPHORE隔离时，Hystrix命令在请求线程上执行。只有在从下游服务器收到响应后才会检测到超时。因此，如果您将 Zuul/Hystrix 配置为超时 5 秒，而您的服务需要 30 秒才能完成，您的客户端将仅在 30 秒后收到超时通知 - 即使服务响应成功 (!)
Netflix 建议默认执行 THREAD，少数情况除外。不幸的是，出于我不知道的原因，SpringCloud Zuul 集成将其更改为 SEMAPHORE。有关详细信息，请参阅 Why is ZUUL forcing a SEMAPHORE isolation to execute its Hystrix commands?。
这解释了为什么您收到 500 错误，尽管已成功联系剩余的实时服务器。
2/重试
功能区用于对远程服务进行实际调用。它使用 Eureka 提供的信息来确定可用的服务和相应的地址。 Eureka 使用每 30 秒更新一次的本地缓存。所以正如@spencergibb 所说，它可能会保留过时的信息一段时间（死服务器）——但这是预料之中的。
功能区在 connect/contact 服务失败时自动重试。它可以配置为在尝试另一个服务器之前重试同一台服务器几次。我不记得默认值和实际配置 属性，但我个人一直在使用以下设置：
# Max number of retries on the same server (excluding the first try)
ribbon.maxAutoRetries = 1
# Max number of next servers to retry (excluding the first server)
ribbon.MaxAutoRetriesNextServer = 2
3/ 连接超时
从您的日志看来，尝试连接到远程服务大约需要 1 秒才能失败。这对于停止服务来说非常长。尝试连接到没有服务侦听的 TCP 端口应该立即失败（至少如果 host/ip 是可访问的并且连接尝试不会在无效中结束）...
连接超时由以下内容控制 属性 - 确保将其设置为下降值：
# Connect timeout used by Apache HttpClient
ribbon.ConnectTimeout=3000
# Read timeout used by Apache HttpClient
ribbon.ReadTimeout=5000
希望这些信息能帮助您解决问题 ;-)