The Microservices approach is a new way of building composable, cloud-native applications. This session is designed for developers who are transforming existing applications to Microservices, or creating new Microservices style applications. The session will cover best practices, patterns including Service Registration and Discovery, and key development tools required for building distributed Microservices style applications. The session will also cover best practices for automating the operations of these applications, using container orchestration services.

2. Microservices Patterns
Jim Bugwadia, Nirmata
DEVNET-1184

3. About me
• Founder and CEO at Nirmata
• Software Developer (C++, Java, Javascript, Go)
• Large-scale distributed systems

4. • Why Microservices
• Microservices defined
• Architecture & Design Patterns
• Summary
Agenda

5. Businesses are adopting Microservices for agility at scale
20% of enterprises will adopt Microservices by 2016” -- Gartner

6. A Microservices style application is composed of several cooperating
services, each of which is versioned and deployed individually.
Monolith
ms
msms
ms
Microservices  Agility

7. • The Art of Scalability
AKF Scale Cube
Microservices  Scale

8. Client Load Balancer Application
Application
Application
X-Axis Scaling
scale by replicating the entire application

9. Client Load Balancer Orders
Catalog
Customers
Y-Axis Scaling
scale by splitting the application into components /catalog
/orders
/customers

10. Client Load Balancer
Z-Axis Scaling
scale by splitting the data /catalog[a-i]
/catalog[j-r]
/catalog[s-z]
Catalog
Catalog
Catalog

11. Client Load Balancer
Microservices combine
X-Y axis scaling
Orders
Catalog
Customers
/catalog
/orders
/customers
scale by splitting the application into services,
and replicating each service

12. Client Load Balancer Orders
Catalog
Customers
/catalog
/orders
/customers
scale by splitting the application into services,
and replicating each service
Best scalability
Best resiliency
Best efficiency
Microservices combine
X-Y axis scaling

13. Microservices Defined
1. Elastic: scales up or down independently of other services
2. Resilient: services provide fault isolation boundaries
3. Composable: uniform APIs for each service
4. Minimal: highly cohesive set of entities
5. Complete: loosely coupled with other services
A Microservices application is composed of multiple cooperating services.
Each Service is:

14. Microservices Architecture &
Design Patterns

15. The Monolith Pattern
• Tiered approach
• Modules within each tier are
compiled and integrated
• Easier to build and manage
• Long test cycles for any change
• All-or-nothing deploys
Client
Load Balancer
Application
Database
WebUI
Orders Catalog Customers
Reviews Cart Payments
… … …

16. The Microservices Pattern
• Multiple services with Uniform APIs
• Services can be build, tested, and
deployed separately
• Enables rapid experimentation on
smaller components
• Can have:
• Polyglot languages
• Polyglot data stores
Client
Load Balancer
Gateway
Gateway
Customers
ReviewsPayments
Cart
WebUI
Catalog
Orders

17. Microservices: Inner and Outer Architecture
• Microservices are meant to be simple
• Complexity gets pushed outside the Microservice
• A platform built for Microservices must absorb this
complexity
That [the complexity you removed from your services to simplify them ]
complexity has moved and, I would argue, increased. It now lives in what I
call the ”outer architecture”. -- Gary Olliffe , Research Director at Gartner

18. Service Naming, Registration & Discovery
• Each Service has a well known name
• Each Service Instance dynamically
registers its availability
• Clients can resolve a well known
Service name to the location of an
available Service Instance
connect with me at:
orders.shopping.com
192.168.50.11:9762
192.168.10.7:80808
192.168.3.12:42132192.168.100.23:9065
192.168.100.23:9065
e.g. Netflix OSS, Nirmata Service Networking

19. Service Gateway Pattern
• An entry point for the application
• A single client connection is
multiplexed across backend
services and service instances
• Routes requests based on
content (e.g. URL Path)
• An application can have multiple
gateways
Gateway
Gateway
CustomersWebUI
Catalog
http://shop.io
Load Balancer
/ui
/catalog
/customers
e.g. Zuul, Hipache, Nirmata Gateway Service

20. Mid-tier Load Balancing
• Services in an application need to
communicate
• Each Service is elastic and
resilient
• Scale-out dynamic load balancing
is required
• Client-based LB
• Host-based
• External service
e.g. Zuul, Nirmata Dynamic Proxy
Gateway
Gateway
CustomersCatalog
http://shop.io
Load Balancer
/catalog
/customers
LB

21. Distributed Locks
• Coordinate operations across several
Service Instances
• DB level locks are not enough
• Implementations should provide
Mutex, Semaphore, RWLock
semantics
e.g. Curator / Zookeeper
Lock Service
Server Server Server
Catalog Catalog
Lock /catalog/item/12a91kl
Lock /catalog/item/09a9ab
Unlock /catalog/item/09a9ab
…..
Lock /catalog/item/ij98108
Unlock /catalog/item/ij98108
…..
Shared Work Queue

22. Leader Election
• Select one service instance to perform
a task
• Good for lightweight scheduling of
periodic tasks
• Use different leaders for different
functions
• Run elections periodically
• Nodes can join election at any point
• If leader node goes away, a new
leader is elected
e.g. Curator / Zookeeper
Leader Elector
Server Server Server
Catalog Catalog
-> Elect /catalog/purge-> Elect /catalog/purge
<- Take Leadership

23. Distributed Workflows
• Coordinate execution of a set of tasks
across services instances
• Each task may be executed by a different
services
• Tasks may execute in parallel, and may
have inter-dependencies
Workflow Service
Server Server Server
e.g. AWS SWS, NirmataOSS Workflow
Catalog Catalog

24. Summary

25. Summary
1. Microservices enable agility at scale
2. Microservices push complexity into the platform
3. Microservices require operations tooling and
distributed programming skills

26. Related Sessions
Come try it live @ DevNet Cloud POD #3
DEVNET-1170 - Intercloud Microservices with Docker
and Nirmata
Thursday, Jun 11, 11:00 AM - 11:30 AM,
DevNet Theater
DEVNET-1137 - Application Centric Microservices Wednesday, Jun 10, 3:00 PM - 4:00 PM.
DevNet Theater
DEVNET-2013 - DevOps In Depth - Adrian Cockroft on
Fast Delivery
Tuesday, Jun 9, 1:45 PM - 2:30 PM,
DevNet Theater
BRKDEV-1002 - What's Hot in Containers Thursday, Jun 11, 1:00 PM - 2:30 PM,
30B Upper Level

27. References
• Microservices : Building Services with the Guts on the Outside, Gary Oliffe,
http://blogs.gartner.com/gary-olliffe/2015/01/30/microservices-guts-on-the-
outside/
• Migrating to Cloud Native with Microservices, Adrian Cockroft
http://www.slideshare.net/adriancockcroft/qcon-new-york-speed-and-scale
• Microservices: Decomposing Applications for Deployability and Scalability, Chris
Richardson,
http://www.infoq.com/articles/microservices-intro
• Microservices, James Lewis and Martin Fowler,
http://martinfowler.com/articles/microservices.html
• Cloud native software: Microservices, Jim Bugwadia
http://nirmata.com/2014/07/cloud-native-software-microservices/

28. Thank you

30. Other Interesting Patterns
• CQRS (Command Query Responsibility Segregation)
Separate model updates from views
http://martinfowler.com/bliki/CQRS.html
• Bounded Context
Keep different models independent
http://martinfowler.com/bliki/BoundedContext.html
• Event Sourcing
Use events, with playback, to manage distributed state
http://martinfowler.com/eaaDev/EventSourcing.html

31. Single Sync
• Each user call results in a
single synchronous call
• A user call spawns one or
more Distributed Workflows
• Workflow tasks update user
state via APIs
• Retries and failure recovery
are built-in per tasks
Client
Gateway
Service
Orders Service
Payment
Service
Message Queue
1. Place Order
2. Route Request
3. Validate
& Commit 4. Publish {new order}
5. Handle Payment
6. Publish
{payment update}
7. Update Order

32. Rest Cache
• Services are using REST
APIs to communicate
• Frequent fetching of data
causes latencies
• A local cache can reduce
latencies
• Async Messaging can
update the cache
Orders Service Catalog ServiceREST
Message Queue
Updates
Updates
Catalog
Cache
POST,
PUT,
DELETE