Cloud-native architectures and microservices allow software to be built faster, more resiliently, and scalably. Microservices involve decomposing applications into loosely coupled services that are independently deployable. Key aspects of microservices include explicit interfaces, independent scaling, and fault tolerance through approaches like circuit breakers. Containerization helps with microservices by enabling portable, lightweight execution of individual services. APIs are critical for communication between microservices and services should be stateless and immutable.

1. Prof. dr. Matjaž B. Jurič, UL FRI and Kumuluz Project
Cloud-native Architectures
and Java

2. Software is How Companies Differentiate Themselves
 More and more major businesses and industries are being run on
software and delivered as online services.
 Many of the winners are Silicon Valley-style entrepreneurial
technology companies that are invading and overturning established
industry structures.

3. Digital Business
 Digitalization (digital transformation) is about delivering business
innovation through software.

4. Software is becoming the KEY differentiator
 „In the past 90% of the car value was in hardware. We expect 50% of
value will be in hardware and the other 50% in software.“

5. Gartner Forecast
75%
By 2020, 75 percent of
application purchases
supporting digital business
will be build, not buy.
Forecast Analysis: Enterprise Application
Software, Worldwide, 2Q15 Update.

6. The Challenge
How to build software
Faster
Resilient
Scalable
Engaging

7. Cloud Native Architecture

8. Cloud Native Architecture
Cloud native architecture is
about how software is build,
not where it runs

9. Microservices
An architectural approach, that emphasizes the
decomposition of applications into single-purpose,
loosely coupled services managed by cross-functional
teams, for delivering and maintaining complex software
systems with the velocity and quality required by today’s
digital business

10. Microservice Principles
 Single Responsibility
• Do one thing (but do it well).
 Explicitly published interfaces
 Integrated in a loosely-coupled way
• Synchronous or asynchronous?
• Circuit-breakers
 Designed for failure
• Fault tolerance is a requirement, not a feature

11. Deployment, Execution, Versioning, Scaling
 Each microservice is deployed separately
 Each microservice executes in its own process / virtual machine /
container
 Each microservice can have multiple versions deployed
• All versions executing side-by-side.
 Microservices are scaled horizontally and independently.

12. Microservice Frameworks for Java
 SpringBoot / SpringCloud
 WildFly Swarm
 KumuluzEE
 Dropwizard
 Payara Micro
 Microprofile.io

13. Containers
 Helpful to microservices
• But not a requirement
 Containers are lightweight
• Just like microservices themselves
 Higher density
 Easy to start/stop
 Portability
 Run ONE instance per container
 Expose ONE port per container
 Isn’t a Container Just Like a VM Image? NO
Hardware
Operating System
Container 1
App
Container 2
App
Containers

14. Artifacts Are Now Immutable Containers
 Not EARs, WARs – Containers!
 No more installing a JVM, app server, deploying the artifacts to them
 Build the container once, deploy it anywhere. Can include complex
environment variables, scripts, etc.
 Containers should be free of state and configuration
 Containers should not assume they are able to write to a persistent
local file system

15. Declaratively Build Containers Using Dockerfiles
FROM centos:centos6
# Enable Extra Packages for Enterprise Linux (EPEL) for CentOS
RUN yum install -y epel-release
# Install Node.js and npm
RUN yum install -y nodejs npm
# Install app dependencies
COPY package.json /src/package.json
RUN cd /src; npm install
# Bundle app source
COPY . /src
EXPOSE 8080
CMD ["node", "/src/index.js"]

16. Building Blocks
Service
Discovery
Microservice
Microservice
Microservice
Microservice
Microservice
Client
Client
Client
Client
Queue
AMQP
Microservice
Microservice
Microservice
API
Gateway
API
Gateway
Configuration
Server
Identity and
Access
Management
Logging

17. APIs
 All data exchange between microservices must be through API layer
• No accessing datastores across microservices
 Synchronous
 Asynchrnous
 Streaming
 Event-driven
 REST
 Messaging

18. APIs
 Adopt advanced REST concepts
• Versioning, Links, Paging, Querying, Filtering, Ordering, Etc
 API specification
• OpenAPI / Swagger
• JSON Schema
 Stateless
 Api Management

19. API Gateway
 Builds a JSON response for each type of client – web,
mobile, etc.
 Asynchronously calls each of the N microservices required
to build a response
 Handles security and hides back-end
 Load balances
 Meters APIs
• Rate-limiting
 Logs centrally
 Etc.

20. Circuit-Breakers
 Circuit breakers prevent cascading failures
• Prevent remote calls when a dependency is determined to be
unhealthy
 Cascading failures happen when request-handling threads are
waiting on a response from a remote system
 Rule #1 of microservices – avoid coupling!
 Hystrix
 @EnableCircuitBreaker Microservice
Microservice

21. Principles
Twelve-Factor Applications
Codebase, Dependencies, Config, Backing services, Build,
release, run, Processes, Port binding, Concurrency,
Disposability, Dev/prod parity, Logs, Admin processes

22. Cultural Change
From Silos to DevOps

23. The five stages of Cloud Native
1. DENIAL
2. ANGER
3. BARGAING
4. DEPRESSION
5. ACCEPTANCE

24. e-naslov: http://www.cloud.si
e-naslov: http://www.kumuluz.com
e-pošta: info@cloud.si
HVALA!