There are two instances of an application: instance-1 and instance-2.
Let us assume that
instance-1 is reachable at localhost:8090
instance-2 is reachable at localhost:9080
How do I configure zuul proxy so that --- First visit instance-1 and in case of any exception / failure, switch to instance-2
Note: Not using Eureka
I was able to get it work using hystrix with a facade controller and in the fallback, calling instance-2 via RestTemplate.
But I am looking for some better approach wherein the routing is taken care by Zuul along with mirroring of HTTPHeaders, HttpMethod and other request attributes.
If anyone have tried similar thing, please suggest me.
You can configure Zuul to retry on current and next instance.
zuul:
retryable: true
ribbon:
MaxAutoRetries: 1
MaxAutoRetriesNextServer: 3
OkToRetryOnAllOperations: true
yourApplication:
ribbon:
listOfServers: localhost:8090, localhost:9080
As per above configuration, if routing to 8090 instance fails Zuul will try one more time to connect to 8090 and if that call also fails, Zuul will route to 9080 for the next call. You can read more about these retry configurations here.
Related
I am implementing a service discovery and I evaluating two options: Eureka and Consul.
Help me decide! I am leaning towards Eureka, but I need to clear a main tech problem. My infrastructure is based on openshift. I can have multiple containers running Eureka Servers behind a load balancer. As far as I know each server needs to communicate with each other. Also, Eureka is mainly used with AWS...
(newbie) Question:
1) How can I configure each Eureka Server to communicate with each other? I have a single (load balanced) URL. My fear is that each server potentially may become desynchronized.
2) Am i missing something?
You're right, each of the Eureka Server must communicate with each other. You can also play with regions depending on your approach.
To make it work (without zones), you must configure the property:
eureka.client.service-url.defaultZone: http://1st-eureka-server-ip-or-hostname:port/eureka/,http://2nd-eureka-server-hostname:porta/eureka/
The configuration above accepts a comma-delimited set of IP/hostname of all the Eureka Servers.
If you want to have a multi-zone configuration, I recommend you to read this blog post.
To Configure each Eureka Server to communicate with each other try this way to make a diffrent diffrent zone in resource in folder.
application-zone1.yml
server.port: 8001
eureka:
instance:
hostname: localhost
metadataMap.zone: zone1
application-zone2.yml
server.port: 8002
eureka:
instance:
hostname: 127.0.0.1
metadataMap.zone: zone2
application.yml
client:
register-with-eureka: false
fetch-registry: false
region: region-1
service-url:
zone1: http://localhost:8001/eureka/
zone2: http://127.0.0.1:800/eureka/
availability-zones:
region-1: zone1,zone2
spring.profiles.active: zone1
Follow this tutorial
I have a Spring Boot application with the following config:
eureka:
client:
enabled: true
registerWithEureka: false
serviceUrl:
defaultZone: http://somehost:9999/eureka/
registration:
enabled: false
My service makes use of Eureka to discover external services, but I don't want it to register with Eureka. Despite the above config I still see the following in my logs, which is odd:
DiscoveryClient - Not registering with Eureka server per configuration
...
EurekaServiceRegistry - Registering application foo with eureka with status UP
The first log line makes sense - it's what I want. However, the second log line doesn't make sense given the config. Am I missing a setting?
You didn't missing anything and your configuration is right. The second log just says that what happened in your local process.
The all periodic tasks that are related to actual registration process (ex heartbeat, instance info replication) with Eureka server are not scheduled by your configuration. So registration with Eureka server will not happen.
I am trying to set an eip binding strategy in Eureka server.
Unfortunately i get an exception:
java.lang.RuntimeException: Cannot get cnames bound to the region:txt.ap-southeast-2.null"
The exception is pretty clear about what's happening - it sets the DNS name to use to 'null'.
I have the following in my config:
eureka:
server:
domainName: mydomain.com
Obviously this doesn't seem to be enough.
The Eureka doc seems to suggest this is all i need -https://github.com/Netflix/eureka/wiki/Deploying-Eureka-Servers-in-EC2#configuring-eips-using-dns
Unfortunately this doesn't work. Is there another config parameter i need?
I am a beginner of using Zuul. I would like to create a http proxy for dynamic destination (ip address) from kubernetes. I checked Can Zuul Edge Server be used without Eureka / Ribbon which is helpful, but I don't want to specify lists-of-servers.
What I have now is a simpleRouteFilter extends ZuulFilter based on spring-boot. In the filter, it will change the destination ip address according to what I get from kubernetes. And I also turn off the eureka stuff by using ribbon.eureka.enabled=false.
The problem is that it looks good in the local environment, but after I deploy the project into kubernetes, it will show Load balancer does not have available server for client: sample-all-services, but it indeed works. The reason why I put a sample-all-service (service id) there is that when I remove zuul config in the properties, the zuul function doesn't work properly. And I know that I didn't put any server for that id because it's dynamic.
Question:
(1) Is Zuul fit in my scenario?
(2) if yes, how to tune Zuul confguration to accept all the http requests without showing load balancer not available warn.
(3) Is that something related to the kubernetes?
The yaml file is:
zuul:
routes:
sample-all-services:
path: /**
server:
port: 8080
ribbon:
eureka:
enabled: false
sample-all-services:
ribbon:
ReadTimeout: 15000
Thanks.
My Setup
I have some services that register with Eureka. This registration info is used by Zuul to route requests to my services. Most of these services run on a port like 9999 or 8080. Each service is on it's own EC2 instance, and I have Nginx routing requests from port 80 to the server's port, so that I can keep my Security Group rules simple.
My Problem
When my service registers with Eureka, it gets registered with ${server.port}, which ends up being 8080 or 9999, etc. When Zuul attempts to route to {ec2host}:8080, it gets blocked by my Security Group rules. Based on the documentation, it looks like I should be able to specify a host and port with eureka.instance.hostname and eureka.instance.nonSecurePort. Whether I use those properties or not, my service registers with it's specific port.
Is there a way to get the Eureka client to register my service with port 80, instead of the server's port?