I have one monolith spring web application developed using spring 3.1 and spring-security 3.1 with Java 7 and it is deployed on tomcat 7.
Now I have a new requirement where I have to create a micro-service for a new module using spring boot with java 8. This micro-service will be deployed separately on different EC2 instance.
I am looking for suggestion/idea to access new microservice from my existing spring web application.
How to perform inter process communication within these two spring application?
Can someone provide me any help/pointer?
You can make use of service discovery pattern, which are mainly of two kinds -
Client-side discovery - This is where clients are responsible for figuring out available service instances. Example - Netflix OSS.
Server-side discovery - In this the service instances are registered on the server-side using a service registry. Example - AWS ELB.
You can read a lot about these on the internet. Just remember the keywords.
Hope this helps !
Related
I am trying to learn and create a microservice using Spring Cloud. I am using Spring mvc and Spring Boot for development. I added separate Spring Boot application for both Eureka server and Zuul client. I have three Spring Boot application now. One Sureka server, one for Zuul routing and third one is for my microservice application. I run the Eureka server and the microservice and Zuul found to be running properly in Eureka server UI.
My doubt is that, I am planned to use routing and service discovery in my microservice. So I have a total of three Spring Boot applications. Can I deploy these three applications into AWS Elastic Beanstalk?
When I exploring I found that Pivotal Cloud Foundry topic. Since I am planing to use AWS Elastic Beanstalk. So what is the role of Pivotal Cloud Foundry in my application?
I am still confused about microservice development using Spring Cloud.
So there are two elements in your confusion. Is Amazon Beanstalk suitable?
So answer is yes. but you have overhead of orchestrating various services of amazon over then. Basically Amazon Elastic Beanstalk is more form based which means you need to tell what exactly you want to do with application for example route setup , scaling mechanism , application portability, application health management , Integration with external log aggregators etc. This is big learning curve to many people (including me :) ). Where as these with PCF these things are easy and straightforward and sometimes implicitly done.
Now Can I use pivotal cloud foundry with amazon? answer will be absolutely yes.
Pivotal cloud foundry is Wrapper written over open source Cloud Foundry project.
It is more succinct PaaS option than Amazon Beanstalk. You can host PCF on amazon ec2 ( IaaS )boxes using BOSH software. To answer you PCF is a alternative to Amazon Beanstalk. You don't need PCF is you want to use Amazon Beanstalk and vice versa.
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.
Everything I found on the internet about Spring Cloud Netflix is about running microservices from Boot applications using #EnableEurekaClients and so on.
Now I'm trying to connect my logging microservice within a traditional war application (springmvc, jaxws etc) - piece of legacy which can not be converted to Boot or modified in any way (by technical task).
I've created a new maven module "log-server-client" that knows nothing about upper web layer and intended to be used as a simple dependency in any maven project.
How should I configure access to Spring Cloud Netflix for this simple dependency? At least, how to configure Eureka and Ribbon?
I just extracted some lines of code from RestTemplate and created my custom JmsTemplate (microservice works with jms remoting with apache camel and activemq), exactly how it is done in RestTemplate, but this code stil lacks connection to infrastructure
afaik, we can create a global singleton bean, run a separate thread from this bean, and run Boot app from this thread, but don't you think that it is very ugly and can lead to problems? How it really should be used?
Great question!
One approach is to use a "sidecar". This seems to be a companion Spring Boot application that registers with the Eureka Server on behalf of your traditional web app.
See e.g.:
http://www.java-allandsundry.com/2015/09/spring-cloud-sidecar.html
http://cloud.spring.io/spring-cloud-netflix/spring-cloud-netflix.html#_polyglot_support_with_sidecar
Another approach is to use the following library:
"A small lib to allow registration of legacy applications in Eureka service discovery."
https://github.com/sawano/eureka-legacy-registrar
This library can be used outside of Spring Boot.
Some Web Application is managed by Spring 4.0 Framework, the Spring Security 3.2 is used also to authenticate users with remember Me feature.
The remember Me and Security is realized by JDBC Support (the needed data are saved in database).
A lot of Spring Beans is used, that are created as "spring" singletons
This Web Applicaton runs in TOMCAT7 Servlet Container, that installed in "classic" Host Sever.
This web application will be runs in production within TOMCAT7, that managed by some Cloud Provider - either in AWS Elastic Beanstalk or in EC2 Instance direct with instaled TOMCAT with autoscaling
That means, that at the first moment runs only ONE EC2 Instance, that has running TOMCAT Server 1. This server has initialized Spring Beans, holding in JVM 1.
But at "peak time" the second instance of EC2 will be started. The TOMCAT2 Server will be started also.
Is it possible, that a USER1, that was authenticated at first moment on TOMCAT1, have a problem with authentication and other business operations realized in WEb Application, if the load balancer routes the user1'Requests after start of TOMMCAT2 to TOMCAT2???
i don't know, whether Spring 4.0 or Spring Security are stateless by default.
You can consider using Elastic Load Balancer sticky sessions for your application.
Read about using Sticky Sesions here:
http://docs.aws.amazon.com/ElasticLoadBalancing/latest/DeveloperGuide/US_StickySessions.html
Read about using Sticky Sessions with Elastic Beanstalk here:
http://docs.aws.amazon.com/elasticbeanstalk/latest/dg/using-features.managing.elb.html
Read about Stickiness policy here:
http://docs.aws.amazon.com/elasticbeanstalk/latest/dg/command-options.html