We have an infrastructure with service discovery and load balancing (i.e. server side with STM and weblogic cluster). Now we are in the process of refactoring into micro-services. We would need an API gateway which does basic routing to other microservices. Netflix Zuul looks a good candidate however I could not get Zuul working without Eureka - but we do not need Eureka since we already have service discovery and load balancing in place.
Is it possible to use Zuul without Eureka and Ribbon?
If yes please provide some guild-lines since the there's no mention about in the wiki.
Thanks.
Yes, it is totally possible.You have to use #EnableZuulProxy on your config class and config it something like this :
zuul:
routes:
yourService:
path: /yourService/**
serviceId: yourService
ribbon:
eureka:
enabled: false
yourService:
ribbon:
listOfServers: localhost:8080
A sample usage can be like this:
shared.microservice.customer.service1.url=zttp://127.0.0.1:8080/shared/microservice/customer/
shared.microservice.customer.service2.url=zttp://127.0.0.1:8181/shared/microservice/customer/
ribbon.eureka.enabled = false
zuul.routes.customer-micro-service.path: /shared/microservice/customer/**
zuul.routes.customer-micro-service.serviceId: customers
customers.ribbon.listOfServers =
zttp://ip:port1/shared/microservice/customer/,zttp://ip2:port2/shared/microservice/customer/
Yes, Of course you can. Actually, by default, if you use #EnableZuulProxy with the Spring Boot Actuator, you enable two additional endpoints:
Routes
Filters
application.yaml
zuul:
routes:
users:
path: /myusers/**
url: https://example.com/users_service
These simple url-routes do not get executed as a HystrixCommand, nor do they load-balance multiple URLs with Ribbon.
Yo can get more information from here.
Related
In a spring-cloud-netflix setup (everything uses feign,ribbon,eureka,zuul), is there any simple/elegant/out-of-the-box way (i.e. discovery based on serviceId vs URL) for CompositeAB to communicate to ServiceA and ServiceB through Zuul? In all of the examples I've seen, CompositeAB discovers and calls ServiceA directly vs. via the Zuul route for ServiceA.
Put another way, if ServiceA registers itself in Eureka as service-a, is the automatically created Zuul proxy for service-a exposed in Eureka in any discoverable way?
For real world context, this relates to network topology and firewalls (there's no direct route between CompositeAB and ServiceA - everything needs to go through the gateway). Using URLs in CompositeAB isn't awful, but seems to defeat the purpose of having the registry present (ideally, Zuul would register the proxy for service-a as something like "zuul-service-a" in the registry). That said, i do get how this particular use case doesn't really fit Zuul's purpose as an edge gateway.
Finally, i think i know how to get my desired effect through code - just wanted to check that i wasn't reinventing any wheels first.
Make sure that your Zuul proxy is registering with Eureka and fetching the registry. Any service that registers with eureka will get a route.
You don't have to allow every service that registers with eureka to be accessible via the proxy either.
A sample application.yml for your Zuul proxy that only allows service-a and service-b:
eureka:
client:
fetchRegistry: true
zuul:
add-proxy-headers: true
ignored-services: "*"
routes:
service-a:
serviceId: service-a
service-b:
serviceId: service-b
Lets consider the following situation.This example will only have urls containing localhost. I have a zuul proxy setup and lets say its running on port 8080. So
Zuul proxy-
localhost:8080
I have an eureka server setup running on port 81.
Eureka server-
localhost:8081.
I have an application lets call it by name-example which is a REST web service. Its running on 3 different ports 82,83 and 84. All 3 instances are registered with eureka server. I have a filter setup in zuul for the uri /example.
So i expect consumers to call the zuul proxy at locahost:8080/example.
Now, in the application example for the request mapping /example, there is a controller setup.
So what i want to do is basically have the consumers call localhost:8080/example and route that request to localhost:8082/example, localhost:8083/example, localhost:8084/example . I know how to load balance using ribbon and eureka and have all the appropriate properties set to achieve that.
zuul.routes.example.serviceid=example
ribbon.eureka.enabled=true.
What i want to do is have ribbon look up the list of url(s) from eureka server and then call localhost:8082/example rather localhost:8082.
Is this possible?
Thank you in advance.
You need to specify the path & serviceId
zuul:
routes:
examplepath:
path: /example/**
serviceId: name-example
stripPrefix: false
The serviceId is the name registered with Eureka. Hope you are specifying Eureka server details in you Zuul gateway.
I have a python web app, and registered with eureka using restfull api[https://github.com/Netflix/eureka/wiki/Eureka-REST-operations], and I found it status UP on the eureka web page, but my gateway server(also registered with eureka) can not find it, I call the url "gateway-server-host/myapp-url" and the following response is:
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)
...
Caused by: com.netflix.client.ClientException: Load balancer does not
have available server for client: test at
com.netflix.loadbalancer.LoadBalancerContext.getServerFromLoadBalancer(LoadBalancerContext.java:483)
at
com.netflix.loadbalancer.reactive.LoadBalancerCommand$1.call(LoadBalancerCommand.java:184)
at
com.netflix.loadbalancer.reactive.LoadBalancerCommand$1.call(LoadBalancerCommand.java:180)
any advise for this problem???
Have you looked over Spring Cloud's Sidecar ?
It basically a service over your non-jvm language service (in your case python) and with sidecar service (you have to deploy your python service and the sidecar service on the same host, if I am not mistaken) and you will include in your Zuul the endpoint to the sidecar service, which will try to handle things like eureka and such.
You spin up a new spring-boot app, with #EnableSidecar annotated, you configure the health-uri and port
example application.yml
server:
port: 5678
spring:
application:
name: sidecar
sidecar:
port: 8000
health-uri: http://localhost:8000/health.json
You can checkout Spring Cloud's documentation regarding Sidecar here for more details how to set it up
Since you are using Zuul you need to manually register routes. Its okay for them to just include the application name, from Eureka.
Example of Zuul route config:
zuul:
routes:
application1: /app1/**
application2: /app2/**
application3:
path: /app3/**
url: http://10.0.8.11:3000/
applicationN is the name registred in Eureka. The url will be resolved and load balanced automatically. For app3 the url is manually specified.
Adding Sidecar solves this problem to an extent where your Zuul /routes shows the registered Application Name.
You must have experienced , even if you do not have an actual app and just put any name with a payload following this document - [https://github.com/Netflix/eureka/wiki/Eureka-REST-operations] , that too gets registered in Eureka as an app.
I have a microservice that uses #FeignClient predominantly to talk to other micro-services. This works beautifuly using Eureka's service discovery mechanism.
Now I have a pressing need to use a #FeignClient to connect to an external system and still perform load balancing using configurations as shown below.
Feign client:
#FeignClient("externalServers")
public interface ExternalServersClient {
#RequestMapping(method = RequestMethod.GET, value = "/someExternalUrl")
ResponseEntity<Object> callExternalServer();
}
application.yml:
externalServers:
ribbon:
listOfServers: server1:18201,server2:18201
From many documentations that I have gone through, it is adviced to disable eureka to allow loadbalancing to be picked up from available listOfServers. I did follow that up and used following configuration to disable it.
application.yml:
ribbon:
eureka:
enabled: false
This allowed me to perform loadbalancing for feign client targeting external systems but all other feign clients that need to use service discovery broke.
Is there any way to disable eureka for feign client setup for external system alone but allow it to function normally for other clients?
Thanks in advance!
In spring-cloud-netflix 1.2.0 (part of the Camden release train), the ability to set the server list implementation was recently added.
You'll be able to do the following:
externalServers:
ribbon:
NIWSServerListClassName: com.netflix.loadbalancer.ConfigurationBasedServerList
listOfServers: server1:18201,server2:18201
Probably released sometime in August or September.
I have a Spring Cloud app that serves as Zuul Server (with #EnableZuulProxy) annotation. At this stage I have /api/* requests routed to proper middletier services, while all other requests routed to the presentation service, so from the configuration pov it looks like below:
zuul:
ignoredServices: '*'
routes:
reservation-owner:
path: /api/service1
url: http://service1.net
--- here couple of other api mappings --
ui:
path: /**
url: http://presentation-service.net/
This works great until I want to check any of the Actuator endpoints on the zuul proxy. Since they fall under the /**, they get routed to the presentation service.
I tried already setting specific endpoints to route to back to the zuul server, but if I am right, I end up with infinite loop of zuul calling itself. So if I am right, I am looking for a way to define path for presentation service that would include everything except of e.g. /admin/* endpoints. Is it possible? Or there is another approach that should be taken?
As soon as you set /** zuul swallows all requests. The only way to do it at that point, is to set the management port.
management.port=8081
pom.xml:
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-actuator</artifactId>
</dependency>
application.yml:
management:
endpoints:
web:
exposure:
include: "*"
Actuator endpoints here
Modifying application.yaml worked for me to routes and filters endpoints:
management:
endpoints:
web:
exposure:
include: 'routes,filters'