I'm doing an app with Spring boot and Spring Cloud, have 2 microservices. I'm using Eureka Server to register both microservices as a clients, but I want to replicate one of them.
How can I do that? I saw info on Google, but seems like I need to replicate Eureka Server, and I don't understand it.
Is it possible to replicate one eureka Client?
Thank you in advance!
I tried to replicate eureka server, but it's not the thing that I want to do. I want to replicate a client.
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I am currently working on a POC about client side load balancing.
I thought to use Spring Cloud Loadbalancer for that. But unlike Netflix Ribbon, I could not find a way to configure Spring Cloud Loadbalancer to work without a discovery server such as Eureka.
Please could you let me know if there is a way to configure it to work without a discovery server (just by giving a list of ip addresses) .
Thanks
I am following a course about microservice architecture using spring, covering netflix's eureka.
The clientui serves webpages and calls the 3 microservices when needed.
The config-server serves configuration for the 3 microservices from a git repo.
Of course the 3 microservices are registered as eureka clients.
My questions are :
should the config server and also be registered as an eureka client, or is there no benefit in doing so?
what about the clientui (which is the web entry point) ? can it be registered as an eureka client in order to benefit from load balancing system and if yes, how then should the app be accessed by clients?
About your first question :- Yes you can register config server as eureka client. Benefit of this will be that in terms of service management it will give you a single point of visibility of all the services. Also later if you try to expand your app in terms of distributed architecture and say you implement an api gateway like zuul, it will be easy for you to setup a fallback config server say if one config server goes down requests can be routed to other config server and so on.
About your second question :- Honestly speaking , I didn't understand it very well in first place. I have never seen any ui service registering to eureka so I am not very sure about this. Still if you have more doubts about it , you can let me know like is it a angular ui or is it a http based client or what.
Was wondering the recommended way of starting a spring boot app if the Spring cloud config server is temporarily down or unavailable. What would be the approach? I know of the retry configurations, but I am wondering if there is a way to have a 'replica' config server and use that as a failover (or something along those lines).
Sure, why not?
After all, spring-cloud-config server exposes rest API and all the interaction with spring boot microservices is done over HTTP.
From this point of view, you can scale out the spring cloud config server by providing more than one instance of it all are up-and-running and mapping them to one virtual IP.
If you're running in some kind of orchestrated environment (like kubernetes) it is a very easy thing to do.
I am trying to build a simple application with microservices architecture.
Below are the details about 3 microservices I have created.
1] Customer.
database: mongodb
server : embeded tomcat server.
port : 8081
2] vendor.
database: mongodb
server : embeded tomcat server.
port : 8082
3] product.
database: mongodb
server : embeded tomcat server.
port : 8083
All the 3 micros runs on an embeded tomcat server.
Now I want to create a common gateway for all these micros [API gateway].
which help me to route my request based on the request I get for example:-
for example if I get a request of http://hostname:port_of_gateway/customer.
on reading this I need to route the request tom my customer micro and fetch its response and send it back to client.
Which of the spring tool I can use to achieve this?
Because your requirements are quite simple you can implement such a gateway by yourself. Here's an example.
But if you really want to use some Spring solution you can try to use Spring Cloud Netflix which is a part of Spring Cloud umbrella project. It includes router and filter features which in turn based on Netflix Zuul gateway service.
Note that this is not a complete standalone application but a library. Therefore you still should create another microservice that would act as API gateway in your application. To make it a gateway you should just add #EnableZuulProxy annotation to the same class that has #SrpingBootApplication annotation. You can find a very good example here.
Please also note that you should somehow inform the gateway about your microservices' addresses for redirection. It can be done in two general ways:
By statically defining the addresses in gateway microservice's configuration;
By applying service discovery pattern in conjunction with e.g. Netflix Eureka service registry.
The 1st approach is easy and straightforward but is not very well for large number of microservices and/or when microservices' locations can change dynamically (e.g. due to auto-scaling).
The 2nd approach requires additional component - service registry - and needs modification of other microservices (to let them register themselves in the registry). This is quite more complicated approach but is the only possible in case of complex architecture. Simple yet expressive example can be found in the same article.
UPDATE (January'19)
As of December 2018 the Spring Cloud team announced that almost all Netflix components in Spring Cloud (except Eureka) entered maintenance mode. It means that for the next year they won't receive any feature updates (only bugs and security fixes).
There are replacements for all the affected components, including Netflix Zuul aforementioned above. So please consider using Spring Cloud Gateway instead of it in new projects.
With regards to the Netflix Eureka Service Registry, I have setup the Eureka Netflix Server using Tomcat 8.0.35 successfully. I have also got the basic Example Service & Client to communicate with each other. I'm still new to Eureka and the management decision is to use Eureka with Spring as several new applications are written around the Spring framework.
I have been following the wiki in order to understand how the communication works (But with little to no success with registering services).. Eureka Github Wiki.
My question is: Do I need to create my own Eureka Service & Client in order to maintain a registry of about 50 cloud instances? (If so, can you please point me in the right direction).
I have hands on experience with Consul/RESTfull API, and have implemented Consul in production (using php, and qbit); however the Netflix Eureka Registry look's as though I need to learn eureka/spring + client/server java programming? I'm still getting used to the following terms.
Eureka Server (I successfully got this working using Tomcat8/JDK1.8 + the eureka.war)
Eureka Service (Some kind of stand-alone RESTfull service that queries the Eureka-Server and listens for client requests)
Eureka Client (Java snippet to be embedded into the Java servlets/jsp)?
Zuul (A type of routing/load-balancing app - similar to HaProxy ?)
Ribbon (A type of routing/load-balancing app - similar to HaProxy ?)
I would like to get the Service & Client configured for mostly non-AWS cloud instances. The Eureka Wiki is not very helpful when it comes to creating a working eureka service & client. Any help to point me in the right direction to implement a Eureka based RESTfull system would be helpful.
I suggest you to read this documentation about spring-cloud : http://cloud.spring.io/spring-cloud-static/spring-cloud.html
It should be a good start to setup a few simple spring-boot/spring-cloud services and start to use advanced tools like zuul/ribbon/hystrix ...
There is a simple example of distributed system using Spring Boot and Spring Cloud Netflix.
This project contains the following microservices:
requestor and responder which communicates via REST/HTTP
gateway microservice - Spring Boot app + Zuul
discovery microservice - Spring Boot app + Eureka
Moreover, requestor microservice uses Hystrix library.
As you can see, Spring Cloud provides a really good wrapper for Netflix solutions. As a result, you can start quickly with minimal configuration.