Zuul forwarding error

Question

I am facing issues using Zuul and Ribbon. I am using also Eureka for microservice registry.

• I have ribbon-service(port 9000) communicating with the user-service using the REST API
• user-service has 2 instances (on port 8081 and 8091)
• on ribbon-service I have implemented client-side load balancing using hystrix and feign client
• I consume ribbon-service API using Zuul route, and this API then triggers user-service API

When I start my microservice ecosystem and try to consume ribbon-service API(zuulservice:8761/ribbon-service/) I get the following error:

com.netflix.zuul.exception.ZuulException: Forwarding error at org.springframework.cloud.netflix.zuul.filters.route.RibbonRoutingFilter.handleException(RibbonRoutingFilter.java:189) ~[spring-cloud-netflix-zuul-2.0.0.RELEASE.jar:2.0.0.RELEASE] at org.springframework.cloud.netflix.zuul.filters.route.RibbonRoutingFilter.forward(RibbonRoutingFilter.java:164) ~[spring-cloud-netflix-zuul-2.0.0.RELEASE.jar:2.0.0.RELEASE] at org.springframework.cloud.netflix.zuul.filters.route.RibbonRoutingFilter.run(RibbonRoutingFilter.java:112) ~[spring-cloud-netflix-zuul-2.0.0.RELEASE.jar:2.0.0.RELEASE] at com.netflix.zuul.ZuulFilter.runFilter(ZuulFilter.java:117) ~[zuul-core-1.3.1.jar:1.3.1] at com.netflix.zuul.FilterProcessor.processZuulFilter(FilterProcessor.java:193) ~[zuul-core-1.3.1.jar:1.3.1] at com.netflix.zuul.FilterProcessor.runFilters(FilterProcessor.java:157) ~[zuul-core-1.3.1.jar:1.3.1] at com.netflix.zuul.FilterProcessor.route(FilterProcessor.java:118) ~[zuul-core-1.3.1.jar:1.3.1] at com.netflix.zuul.ZuulRunner.route(ZuulRunner.java:96) ~[zuul-core-1.3.1.jar:1.3.1] at com.netflix.zuul.http.ZuulServlet.route(ZuulServlet.java:116) ~[zuul-core-1.3.1.jar:1.3.1] at com.netflix.zuul.http.ZuulServlet.service(ZuulServlet.java:81) ~[zuul-core-1.3.1.jar:1.3.1] at org.springframework.web.servlet.mvc.ServletWrappingController.handleRequestInternal(ServletWrappingController.java:165) [spring-webmvc-5.0.5.RELEASE.jar:5.0.5.RELEASE] at org.springframework.cloud.netflix.zuul.web.ZuulController.handleRequest(ZuulController.java:44) [spring-cloud-netflix-zuul-2.0.0.RELEASE.jar:2.0.0.RELEASE] at org.springframework.web.servlet.mvc.SimpleControllerHandlerAdapter.handle(SimpleControllerHandlerAdapter.java:52) [spring-webmvc-5.0.5.RELEASE.jar:5.0.5.RELEASE] at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:991) [spring-webmvc-5.0.5.RELEASE.jar:5.0.5.RELEASE] at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:925) [spring-webmvc-5.0.5.RELEASE.jar:5.0.5.RELEASE]................ Caused by: com.netflix.client.ClientException: Load balancer does not have available server for client: ribbon-service at com.netflix.loadbalancer.LoadBalancerContext.getServerFromLoadBalancer(LoadBalancerContext.java:483) ~[ribbon-loadbalancer-2.2.5.jar:2.2.5] at com.netflix.loadbalancer.reactive.LoadBalancerCommand$1.call(LoadBalancerCommand.java:184) ~[ribbon-loadbalancer-2.2.5.jar:2.2.5] at com.netflix.loadbalancer.reactive.LoadBalancerCommand$1.call(LoadBalancerCommand.java:180) ~[ribbon-loadbalancer-2.2.5.jar:2.2.5] at rx.Observable.unsafeSubscribe(Observable.java:10327) ~[rxjava-1.3.8.jar:1.3.8] at rx.internal.operators.OnSubscribeConcatMap.call(OnSubscribeConcatMap.java:94) ~[rxjava-1.3.8.jar:1.3.8] at rx.internal.operators.OnSubscribeConcatMap.call(OnSubscribeConcatMap.java:42) ~[rxjava-1.3.8.jar:1.3.8] at rx.Observable.unsafeSubscribe(Observable.java:10327) ~[rxjava-1.3.8.jar:1.3.8]

This error remains for some time, and after that time I get the following output:

2018-07-16 12:55:43.260 INFO 19233 --- [erListUpdater-0] c.netflix.config.ChainedDynamicProperty : Flipping property: ribbon-service.ribbon.ActiveConnectionsLimit to use NEXT property: niws.loadbalancer.availabilityFilteringRule.activeConnectionsLimit = 2147483647

After that output everthing works great again.

When I hit eurekaservice:8765/eureka/apps I have registered both ribbon-service and all the user-service instances.

This is my zuul service application.properties:

> #Service port
server.port=8765

#Service port
spring.application.name=zuul-service

# Discovery Server Access
 eureka.client.service-url.defaultZone:http://localhost:8761/eureka/
 eureka.instance.lease-renewal-interval-in-seconds=3

 #User service configuration
 zuul.routes.user-service.path:/user-service/**
 zuul.routes.user-service.serviceId:user-service

 #Product service configuration
 zuul.routes.product-service.path:/product-service/**
 zuul.routes.product-service.serviceId:product-service

 #Product service configuration
 zuul.routes.shoppingcart-service.path:/shoppingcart-service/**
 zuul.routes.shoppingcart-service.serviceId:shoppingcart-service

 #Product service configuration
 zuul.routes.payment-service.path:/payment-service/**
 zuul.routes.payment-service.serviceId:payment-service

  #Product service configuration
 zuul.routes.ribbon-service.path:/ribbon-service/**
 zuul.routes.ribbon-service.serviceId:ribbon-service

This is my zuul-service bootstrap.properties:

> #Application name
spring.application.name=zuul-service

#hystrix.command.default.execution.isolation.thread.timeoutInMilliseconds: 12600
ribbon.ConnectTimeout: 6000   
ribbon.ReadTimeout: 60000
robbon.eureka.enabled: true

hystrix.command.default.execution.timeout.enabled=false

I am using spring 2.0.1 and spring cloud Finchley.RELEASE.

Can somebody explain what is going on?

Thank you!

Answer 1

You may consider add strip path config for your zuul configuration.

add stripPrefix=false in every route config

Answer 2

The way DiscoveryClient works is that it fetches new list of changes from Eureka (Service discovery) for every defined time period called hearbeat. Until new changes with respect to registered applications propagates from service discovery to your Zuul instance it is bound to have errors.

The output you see in the logs is just the confirmation that it has received this information.