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
Related
I am using netflix-eureka as the discovery service in my spring-cloud application.
Currently facing a problem where if I have all microservices registered to eureka server, they work perfectly fine. However, If i change networks (Get home from office or vice versa) the services become unresponsive unless I restart all the microservices.
I have also noticed that with office net the services are registered against their respective IP addresses, while at home they seem to get registered against the host name.
I already have the 'prefer-ip-address' config set to true.
The following is the configuration in each microservice:
eureka:
client:
fetch-registry: true
register-with-eureka: true
service-url:
defaultZone: http://localhost:8761/eureka
instance:
prefer-ip-address: true
hostname: localhost
Any idea why changing networks would cause this issue or why the services are registered against host name despite 'prefer-ip-address' set to true?
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.
I have a set of micro-services which need to communicate to each other.
The total number of micro-services does not fit to single physical server so I need to spread them out among 2 different servers.
My idea (do not know if correct) is to have spring-eureka instance per server to which all services from this particular server register. So:
Services (A,B) register to Eureka on Server 1.
Services (C,D) register to Eureka on Server 2.
After that eureka instances will exchange their knowledge (Peer Awareness).
The questions are:
Does described idea is correct approach? Or rather there should exist just single Eureka instance on single server to which all services from both servers will register (i.e. Eureka exists only on Server1)?
If described idea is correct then as I understand ports 8761 should be opened on Server1 and Server2 to allow communication between "Eurekas"? And the configuration should be as following:
Eureka on Server 1:
eureka.client.serviceUrl.defaultZone: http[s]://server2address:8761/eureka/
Eureka on Server 2:
eureka.client.serviceUrl.defaultZone: http[s]://server1address:8761/eureka/
1) normally you would have a server for each service (A,B,C,D eureka1 and eureka2)
2) eureka.client.serviceUrl.defaultZone is a comma separated list so it is more like "eureka.client.serviceUrl.defaultZone: http[s]://server1address:8761/eureka/,http[s]://server2address:8761/eureka/" for each service
Hope that helps, cheers
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.
I am researching about Eureka for services discovery and I found out that if I kill a process, eureka displays it as "DOWN". Will it clean it and remove it on it's own someday?
The scenario is this: Lets say I am working with amazon AWS. I want to upload a new version this way: prepare X new machines and kill the old ones.
The new machines will register to eureka on startup, but how will the old machines be unregistered from Eureka?
I use java and spring-cloud.
Thanks,
Ido
Not sure if this will help you but you can try this.
Eureka server application.yml
eureka:
server:
enableSelfPreservation: false
Service application.yml
eureka:
instance:
leaseRenewalIntervalInSeconds: 1
leaseExpirationDurationInSeconds: 2
Read this for info:- https://github.com/ExampleDriven/spring-cloud-eureka-example