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
Related
What are the benefits to use "spring service discovery kubernetes" instead of using directly the Service DNS coming from Kubernetes?
I mean, If I deploy in kubernetes 2 services (service-a and service-b), and service-b exposes a Rest API.
service-a can easily connect to service-b using the url "http://service-b/...".
Question #1. In order to let service-a be able to connect to service-b using the service DNS, service-b has to be deployed before service-a?
Question #2. What are the pros/cons using the spring discovery?
Question #1:
No, the order in which you deploy the services is not important to use the kubernetes DNS services to resolve the ips, the only thing here is that if you deploy serviceA after serviceB, you will have in serviceA as an environment variable the ip of serviceB but not the inverse.
Question #2:
The spring service discovery is an alternative to the native kubernetes service discovery and it is used by other spring cloud projects like spring-cloud-eureka to perform the service discovery. The only pros I see in this approach is that you can custom the load balancing algorithm tath you can use to spread the load among the different instances
I want to setup Eureka server for service registry and erueka clients that will get access rest api using the service registry from Eureka server. But we use mesos as our container management system and when we start the Eureka server we will not know which host and port it is running on. So there is an api that we can use that gives us the complete url where Eureka server will be running. Now all the examples for Eureka client that I have seen have hard coded the Eureka server in the config file. Is it possible for Eureka clients to use that api and get the url for Eureka server.
FYI: we are using spring boot and have our own DC and are not on any cloud
I think I found the answer but if someone can confirm that will be great. I need to create my own EurekaClientConfigBean and override the following methods:
public void setEurekaServiceUrlPollIntervalSeconds(int eurekaServiceUrlPollIntervalSeconds)
List<String> getEurekaServerServiceUrls(String zone);
I am creating a simple project in microservices using spring boot and netflix OSS to get my hands dirty. I have created two services
config service which has to register itself in discovery(eureka)
service.
discovery service which requires config service to be running to get its configuration.
Now when I am starting these services, both services fails due to inter dependency. What are the best practices resolve this issue and which one to start first.
PS:- I know I am creating circular dependency, But what is the way to deal with situation like this where I want to keep eureka configuration also with the config server
Thanks
I believe that you can find the answer for your question in the official spring cloud config server documentation:
Here: http://cloud.spring.io/spring-cloud-config/spring-cloud-config.html#_spring_cloud_config_client
Basically you have to choose between a "Config First Bootstrap" or "Discovery First Bootstrap".
From the docs:
"If you are using a `DiscoveryClient implementation, such as Spring Cloud Netflix and Eureka Service Discovery or Spring Cloud Consul (Spring Cloud Zookeeper does not support this yet), then you can have the Config Server register with the Discovery Service if you want to, but in the default "Config First" mode, clients won’t be able to take advantage of the registration.
If you prefer to use DiscoveryClient to locate the Config Server, you can do that by setting spring.cloud.config.discovery.enabled=true (default "false"). The net result of that is that client apps all need a bootstrap.yml (or an environment variable) with the appropriate discovery configuration. (...)"
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.
Is Spring cloud config server an example of sidecar application for microservices?
Do you mean if the Spring Cloud Config Server itself is what the Spring Cloud documentation labels as Sidecar? Then no, as far as I know it is just a plain, regular Spring Boot app.
A Sidecar as referred to in Polyglot support with Sidecar is a Spring Boot application that acts as a bridge between your service infrastructure and a service that is not written in a JVM language. Apps written in Python, Go, Ruby, C#, NodeJS, Erlang or really any other language that can bind something to a port come to mind.
The benefits of the Sidecar are, that your Non-JVM apps
service discovery become automatically discoverable through Eureka, which means that JVM services can resolve the host:port/<service-id> of the Non-JVM apps as well as the other way around,
monitoring are monitorable through the same health-endpoints-infrastructure that is available in Spring Boot (Actuator), i.e. by manually providing the health endpoint in the Non-JVM app Eureka knows when the Non-JVM service is down
routing/proxying query the services by either manually looking up their hosts/ports or proxying these requests through Zuul, which in turn resolves their current addresses through Eureka
balancing be load balanced by Ribbon and
configuration may consume configuration properties provided via Spring Cloud Config.
I hope this answer addresses your question, if not (or someone finds it to be inaccurate or misleading) just let me know and I delete it to make room for something more suitable. ;-)