This document discusses microservices and containers. It begins with an introduction to microservices and the key challenges they address in monolithic architectures. It then discusses how containers, specifically Docker, help address these challenges through lightweight isolation, portability and other features. The remainder of the document discusses how Kubernetes can be used to orchestrate containers and microservices through features like replication, load balancing, service discovery and monitoring.

1. © 2015 ARAVIND AJAD YARRA < 1 >
MICROSERVICES &
CONTAINERS
m a k i n g s e r vi c e s w o r k
μ

2. © 2015 ARAVIND AJAD YARRA < 2 >
ARAVIND AJAD YARRA
 Software Architect & Engineer
for 19 years
 Distinguished Member of
Technical Staff at Wipro

3. © 2015 ARAVIND AJAD YARRA < 3 >
MICROSERVICES
QUICK INTRODUCTION TO MICROSERVICES

4. © 2015 ARAVIND AJAD YARRA < 4 >
SOA CURRENT STATE
ORCEHSTRATION
BUSINESS LOGIC
CHANNELS OLTP WORK-FLOW
DASH
BOARDS
CORE
SYSTEMS
LEGACY
SYSTEMS
DATA
WAREHOUSE
S
PARTNER
SYSTEMS
ENTERPRISE SERVICE BUS
GOVERNANCE
CONNECTIVITY
SERVICE
PROVIDERS/
CLIENTS
SERVICE
CLIENTS/
PROVIDERS
SOA INTEGRATION
MIDDLEWARE
Service Oriented Architectures are currently adopted in Enterprise Integration.

5. © 2015 ARAVIND AJAD YARRA < 5 >
MONOLITH ARCHITECTURE
RWD MVC
Quote HomeCommercial
Cross SellCart Rules Ref Data Bundles
ResumeCaching Document Payment Integration
Validations
Auto
Data Store
Life
UI
JAVAEE
CONTAINER
Monolith architectures have components bundled together with tight
dependencies. Change or failure in a component will result in fragility,
there by makes it difficult to evolve the architecture.

6. © 2015 ARAVIND AJAD YARRA < 6 >
MICROSERVICES
HomeQuote
CommercialQuote
Recommendations
Cart
BundleManagement
Caching Document
Payment
AutoQuote
μ μ μ μ μ μ
μ μμ
• Service Oriented
• Independently managed
• Loose Coupling
• Connected
Applying service oriented architecture principles to monolith system architectures

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WHY CONTAINERS?
PRACTICAL CONSIDERATIONS FOR MICROSERVICES

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KEY CONSIDERATIONS
Design and
development of
services - Service
capabilities such as
connectivity, discovery
and monitoring
Deploy self-contained
services.
Continuous
deployment of services
– enable evolution &
continuous availability
Configure services
externally without fixed
assumptions
Transparently discover
dependent services.
Find failed services
and connect to
resumed services.
Manage services and
Monitor service
specific metrics, events
and logs

9. © 2015 ARAVIND AJAD YARRA < 9 >
KEY CHALLENGES
• Lightweight – How not to add overhead?
• Self-contained – How do we make services portable across
environments? How do we isolate service processes?
• Continuous deployment – How to deploy services rapidly without
any disruption?
• Setup & Discovery – How to setup services and add dependencies?
• Elastic Scaling - How to scale services transparently?
• Monitor – How to monitor services and failures?
Application Stacks have grown up to handle these.
How about infrastructure?

10. © 2015 ARAVIND AJAD YARRA < 10 >
DOCKER MADE FOR μS
Docker makes an excellent choice for micro-services. But is it
enough?
• Isolation : One process per container
• Lightweight : No virtualization overhead
• Self-contained : Package all the hard
dependencies together
• Portable : Easily pull images into any
environment

11. © 2015 ARAVIND AJAD YARRA < 11 >
CONTAINER ORCHESTRATION
Orchestrate containers to facilitate micro-services architecture
 Provision Containers
 Manage Container Dependencies
 Enable Discovery
 Handle Container Failure
 Scale Containers
Amazon ECS

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BRINGING IT ALL TOGETHER
HOW TO MAKE ALL THIS WORK?

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KUBERNETES CLUSTER
Master
Minion
pod pod
labels labels
kubelet cAdvisor proxy
API Server
Minion
pod pod
labels labels
kubelet cAdvisor proxy
scheduler
replication
controller
kubectl
distributed
storage

14. © 2015 ARAVIND AJAD YARRA < 14 >
PACKAGING μS
• Packaging a microservice involves creating a executable JAR or equivalent.
Use Onejar or Spring Boot to build a fat jar with all dependencies
• Create Docker image with the executable for microservice. Use caching as
required
• Pod is the abstraction for a basic unit of
a μS in Kubernetes. Create a Pod with
docker image.

15. © 2015 ARAVIND AJAD YARRA < 15 >
SCALING μS
• Replicating Pods is easy and will replicate containers (& microservices)
• Kubernetes replication controllers are best way to achieve replication
• Replica count can be incremented or decremented as required dynamically
using kubectl or Kubernetes API
• BTW, replication controllers can help in resiliency

16. © 2015 ARAVIND AJAD YARRA < 16 >
LOAD BALANCING
• Load balancing can be enabled using the ‘Service’ construct of Kubernetes.
Service is essentially a proxy on top of Pod.
kube-proxy
Pod #2
Labels: quoteservice
Port: 8080
Pod #3
Labels: quoteservice
Port:8080
Pod #1
Labels: quoteservice
Port:8080
• Load balancing is done using selectors on labels
• Pods are ephemeral and they can come up and go. Service will resolve
those pods randomly.

17. © 2015 ARAVIND AJAD YARRA < 17 >
BG DEPLOYMENT
service
Pod #2
Labels: quoteservice
Port: 8080
Pod #3
Labels: quoteservice
Port:8080
Pod #1
Labels: quoteservice
Port:8080
service
Pod #2
Labels: quoteservice
Port: 8080
Pod #3
Labels: quoteservice
Port:8080
Pod #1
Labels: quoteservice
Port:8080
X
Pod #4
Labels: quoteservice
Port:8080
 Services enables blue-green deployments for continuous deployment
 Services also enable other patterns such as canary releases, taking off
instances for debugging and so on
replcontroller#1#2

18. © 2015 ARAVIND AJAD YARRA < 18 >
SERVICE DISCOVERY
 Environment Variables
 kubelet adds environment variables for every service that is
active in the cluster
 microservices can leverage these environment variables for
resolving dependencies
 SkyDNS with DNS cluster add-on
 Injects SkyDNS (+etcd) to environment variables
 SkyDNS is populated with active services from kubernetes
master
 Higher order frameworks
 Consul
 Eureka

19. © 2015 ARAVIND AJAD YARRA < 19 >
SERVICE MONITORING
 Docker Process Monitoring
 Kubelet monitors docker process constantly
 Failure of docker process triggers restart of the pod based
on policy
 Application Level Health Checks
 HTTP Health Check – Kubelet calls a HTTP endpoint
 Container Exec – Kubelet calls a container command
 Higher Order Frameworks
 Hystrix + Eureka
 Metrics & Log Monitoring
 Heapster
 Fluentd + Elasticsearch

20. © 2015 ARAVIND AJAD YARRA < 20 >
WATCH OUT
 Orchestration of containers for stateful
microservices
 Limited controller capabilities
 Rapidly evolving
 Not yet ready for production
 Limited management capabilities
 Tooling is yet to catch-up
 Read the small print

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THANK YOU
@aravindajad
www.slideshare.net/AravindAjad
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