Microservices Introduction

Justin Lee - Technical Evangelist

E: triplez@justinlee.sg

T: @triplez82

Agenda

Building Monolithic App

Introduction about Microservices

Characteristics of Microservices Architecture

Benefits and Drawbacks of Microservices

Demo of implementing a Microservices Architectured App on Bluemix

Building Monolithic App

What's Great with Monolithic App

* Simple to develop

* Simple to test

* Simple to deploy

* Simple to scale

What's Bad with Monolithic App

* App is overwhelmingly complex. Fixing bugs and implementing new features become difficult & time consuming

* The development will be slow down due to app size

* Very hard to do continuous development (which has been become the new norm in modern SaaS business)

* Difficult to scale when different modules have conflicting resource requirements

* Reliability is an issue i.e a memory leak could impact entire app

* Extremely difficult to adopt new frameworks & technologies

What is Microservices

Microservices are small, autonomous services that work together

Scale Cube

Characteristics of Microservices

1. Small and focused on doing one thing well

* Single Responsibility Principle

Gather together those things that change for the same reason, and separate those things that change for different reasons.

Characteristics of Microservices

2. Autonomous

* Separate entity, can be deployed on isolated "machine"

* Be able to change independently

"Can you make a change to a service and deploy it by itself without changing anything else?"

* Each service expose an API and communicate via API

Characteristics of Microservices

3. Language Neutral

NodeJS

Redis

MongoDB

Ruby

MongoDB

App Re-Architected as Microservices

Benefits of Microservices

1. Technology Heterogeneity

* Pick the right tool for each job

* Able to adopt new technology more quickly

Benefits of Microservices

2. Resilience

* Concept of bulkhead

* We can build system handle total failure of services

Benefits of Microservices

3. Scaling

Benefits of Microservices

4. Ease of Deployment

* Changes can be made to services & deployed independently

* Faster to rollback in case of failure

* Get new functionality to client faster

Benefits of Microservices

5. Organizational Alignment

* Smaller team working on smaller codebases tend to be more productive

* Able to align architecture to organization

* Able to shift ownership of services to teams who are collocate

Benefits of Microservices

6. Composability

* Functionality can be consumed in different ways for different purposes

Benefits of Microservices

7. Optimizing for Replaceability

* Easier to manage the cost of replacing / deletion of services due to its small in size

Drawbacks of Microservices

1. Significant Operations Overhead

* You need a mature operations team to manage lots of services, which are being redeployed regularly.

Drawbacks of Microservices

2. Distributed System Complexity

* Lots of remote procedure calls, REST APIs or messaging to glue components together across different processes and servers.

* Which inter-process communication mechanism to choose?

* Have to concern about Network latency, fault tolerance, message serialisation, unreliable networks, asynchronicity, versioning, varying loads, etc

Drawbacks of Microservices

3. Asynchronicity is Difficult

CAP theorem - you can pick only 2 of these in a distributed system

* Consistency (all nodes see the same data at the same time)

* Availability (a guarantee that every request receives a response about whether it succeeded or failed)

* Partition tolerance (the system continues to operate despite arbitrary partitioning due to network failures)