Introduction.txt

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Microservices - With Spring boot

This tutorial will help you learn the basics of microservices and microservices architctures. Addintionally you can create a simple microservice using Spring Boot.

You will learn:

1) What is monolith?
-> Monolith application are typically huge - more 100.000 lines of code. In some instances even more than million lines of code

-> Monoliths are characterized by:
 - large application size
 - long release cycles
 - large teams

 -> Chalenges for Monolith
 - scalability chalenges
 - new technology adaption
 - deficult to automate tests
 
2) what is a microservice?
-> developing a single application as a suite of small services each running in its own process and communicating with lightweight mechnisms, often an HTTP resources API. (REST)
-> Cloud enabled - dynamic scaling

-> advantages:
 - new technology adoption becomes easier
 - faster release cycles
 - scaling with cloud

3) What are the challenges in Microservices?
- Quick setup needed and automation: because you have a big number of smaller component instead of monolith, you need automate everythin - Build, development, Monitoring etc.
- Bounded contect: diffucult to identify the bounderies of a microservices. Bounded context from Domain Name Driven Design is a good starting point.
- Configuration Management
- Dynamic scale up and scale down in cloud
- Pack of cards: It a microservice at the bottom called fails, it can break all other services. Microservices should be fault tolerant by design
- Debuging: Centralized logging and Dashboard are essential to make it easy to be debug problems

4) How does Spring Boot and Spring Cloud make developing microservice easy?
4.1. Spring Boot
 -> Spring boot is designed to develop microservice using Spring Framework. It is easy to create stand-alone and production ready spring application.
 -> Feature
   - embedded server
   - metrics (monitoring)
  - health checks (monitoring)
  - externalized configuration

4.2 Spring cloud  : solution ro cloud your microservices.
Important Spring Cloud Modules:
-> Dynamic Scale Up and Scale down:
   - Naming Server (Eureka)
   - Ribbon (Client side load balancing)
   - Feign (Easier rest client)

-> Visibility and Monitoring with
    - Zipkin Distributed Tracing
    - Netflix API Gateway

-> Configuration Management with
    - Spring Cloud Config Server

-> Fault Tolerance with
    - Hystrix


5) how to implement the client side load balancing with Ribbon?
- How to implement a Naming Server (Eureka Naming Server)
- How to connect the microservice with Naming Server and Ribbon