we are planning to built our next projects using microservices-architecture and we have already defined that we want to use Zuul as API-Gateway. Right now we have to decide which service registry we will use:
Consul or Eureka.
We want to use server-side load balancing (via Zuul itself). Is it possible to do this while combining Zuul with Consul or Eureka?
Furthermore, we don’t want to use self-registration pattern! Our plan is to use Third-Party registration! Is it possible while combining Zuul with Consul or Eureka? Which tools can be used for this? Are there alternatives for Registrator which works for Docker?
Thanks a lot in advance for your help!
Related
We have load balancing, discovery, etc in the Spring cloud. But the same load balancing, discovery is available in Kubernetes as well. So just wanted to know when we should go with Spring cloud (load balancing or discovery) and when to use Kubernetes
It depends on your use-case. There can be situations where you need to directly use Eureka server registry and Eureka client discovery offered by Spring Cloud Netflix. Ribbon is the client side load balancer provided by Spring Cloud Netflix.
In my experience, it is not impossible to use Eureka in any environment. It can be your local data centre or cloud infrastructure. However when it comes to deployment environment, there are so many alternatives for us to achieve the server registry mechanism. Sometimes those alternatives are the best solutions. I will give you an example below...
If you host your application in your local server (Local data centre)
Now in this scenario you can use Eureka and continue your server registry and discovery mechanism. (That is not the only way. I mentioned Eureka for this scenario because it would be a good use case for it)
If you host your application in AWS infrastructure
The AWS environment gives you lots of benefits and services such that you can forget the burden of maintaining and implementing Eureka. You can achieve simply the same behaviour by AWS load balancers, AWS target groups and even more by adding AWS auto scaling groups. In AWS it self there are so many other ways to achieve this as well.
Long story in short that for your scenario, you can continue using the power of Kubernetes and get the privilege unless you have a specific reason to use Eureka and put a large effort to implement it. You should select what suits the best depending on time, effort, maintainability, performance etc.
Hope this helps for you to get an idea. Happy coding!
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
So I have a very small micro service architecture built using Eureka service discovery. The problem I am facing right now is that I only want my service endpoints to accept request from my api gateway, as it is right now you can just make a request straight to the service and hit that service endpoint. Is this a problem Kubernetes would solve? Or Is there a more practical way of doing this?
You should be using network policies to control the traffic between the services.
In kubernetes the services you want to expose internally use service type ClusterIP. This is default anyway which means services are accessible within cluster only. your api gateway is exposed as load balancer service type which then takes traffic from external world and talks to services internally. Depending on your cloud provider you can use firewall in front of load balancer since you can compromise security by simply exposing load balancer. e.g. azure kubernetes you could use application gateway. You can also replace the api gateway with ingress controller. it's very powerful reverse proxy controller which you can expose directly to traffic and that would talk to your services internally.
You really need to understand concepts so i would recommend following links
https://kubernetes.io/docs/concepts/services-networking/service/
https://blog.getambassador.io/kubernetes-ingress-nodeport-load-balancers-and-ingress-controllers-6e29f1c44f2d
I am learning building microservices using spring boot, Spring Cloud(netflix OSS Components). I have used netflix Eureka for service discovery, zuul for api gateway, ribbon, feign while running in my local machine.
Netflix eureka, zuul, ribbon, feign spring cloud config are not useful when we deploy to PCF?(if yes what are the alternatives available in pcf and how to configure them?)
As who are building microservices follows CI/CD approach, how developer verify working of their micro services before pushing code as we don't use eureka, zuul,ribbon,feign in production pcf. (how to simulate pcf environment in developer machine?).
I'd suggest to read below content before implementing if you have any doubt regarding usage of Eureka and Zuul, you will get all answers yourself.
https://github.com/Netflix/eureka/wiki/Eureka-at-a-glance
https://github.com/Netflix/zuul/wiki
As who are building microservices follows CI/CD approach, how developer verify working of their micro services before pushing code as we don't use eureka, zuul,ribbon,feign in production pcf.
Answer to this question is: You must be aware of JUnit test cases, so you can run you test cases using deployment pipelines to make sure all your functionalities are working as expected or you can use Test Automation for the same.
(how to simulate pcf environment in developer machine?).
Answer to this one:
You can use eclipse plugin you are using eclipse/STS IDE. Or you can connect all PCF services from you local machine using CloudFactory
#Bean
public Cloud cloud() {
return new CloudFactory().getCloud();
}
https://docs.pivotal.io/pivotalcf/2-1/buildpacks/java/sts.html
Here are some thoughts:
Eureka Service discovery: in my opinion this is not strictly necessary when running on PCF. When you push an app on PCF usually a route is assigned to your app, and you can use this Route as a poor man's service discovery. Eureka would allow you to use client-side load balancing in the case of container-to-container networking, but usually you wouldn't need this.
Zuul: Can be very useful also on CloudFoundry in case you are doing things like writing frontend-for-backend services, providing frontends for different devices (mobiles, desktops, i-pads) that use the same backend services. Might also be useful for an authentication/authorization layer or rate-limiting. One native CloudFoundry alternative would be to use route-services for tasks such as rate limiting, authentication/authorization.
spring-cloud-config: makes sense if you want your configuration to be under version control for different environments. This is useful no matter if you are running on CloudFoundry or not. I don't know of any alternatives on plain CloudFoundry.
spring-cloud-feign: makes sense if you want use annotations such as #RequestMapping with your Feign client interfaces. This is independent on if you are running on CloudFoundry or not. AFAIK there are no alternatives for this in case you want to use Spring MVC annotations with Feign.
ribbon: makes sense if you want to use client side load balancing as opposed to let the CloudFoundry router to do the load balancing for you.
How developers can check locally if this works for them:
In general, I don't believe developers should need to check locally if their app is working fine together with zuul, cloud-config-service, and eureka.
They could check this in a dev or test space or environment though.
If they really want to check this on their local machine, they could download PCFDev and run these infrastructure components there.
Hope this helps.
i have created two java spring-boot micro services they are
1) producer
2) consumer
and i have used spring eureka server for service registration and discovery . it worked fine . then what is the use of Netflix Zuul.
Let's suppose you have 20 services to which user can interact to, and of course we are not going to expose each and every services publicly because that will be madness (because all services will have different ports and context), so the best approach will be to use an API gateway which will act as single entry point access to our application (developed in micro service pattern) and that is where Zuul comes into picture. Zuul act as a reverse proxy to all your micro-services running behind it and is capable of following
Authentication
Dynamic Routing
Service Migration
Load Shedding
Security
Static Response handling
Active/Active traffic management
You can go through documentation here
If you have enough experience in the domain, you could look at zuul as an API gateway like Apigee. It is very feature rich and touches up on a lot of different concerns like routing, monitoring and most importantly, security. And eureka as a service discovery platform that allows you to load balance (in Linux terms the nginx or haproxy) and fail over between your service instances.
Typically the backend services that perform the server side business operations (i.e. core) are not exposed publicly due to many reasons. They are shielded by some Gateway layer that also serves as reverse-proxy. Netflix Zuul serves as this gateway layer which easily gives you the capabilities as mentioned by #Apollo and here