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
Related
I need some help in understanding how we implement service discovery for microservices in kubernetes.
Im going through some tutorials on spring boot and noticed that wr need to use Eureka discovery for implementing service discovery for maintaining communication b/w microservices. But my question is if we deploy those spring boot microservices in kubernetes, do we still need to use Eureka tool? We can use kubernetes services for implementing service discovery and load balancing right?
Kubernetes orchestration platform provides CoreDNS for Service discovery. Micro services when they get deployed to the platform can utilise the services by default no need to implement it unless if there is specific requirements which is not satisfied . Kubernetes Loadbalancer services type can be used for load balancing of services
I am going to create a kubernetes cluster to deploy all my spring boot microservices. Currently I have a spring cloud gateway server, a eureka discovery server and my back-end and front-end applications.
Do we need gateway server and discovery server if deployed on kubernetes, as these services are provided as part of cluster?
Thanks.
You are not required to use the Spring Cloud Gateway or Eureka discovery server. Kubernetes provides all basic building blocks (like Service) implemented without additional software requirements (for example with plain DNS).
If you need a more advanced setup you can integrate kubernetes API in Spring applications or use other ways to integrate. For the 90% case there is no need to do so.
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 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. (...)"
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