Meghashyam Varanasi - Associate Director

Cognizant Technology Solutions

Amplifying feedback through Microservices and Containers

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Introduction to the Topic

Micro services Vs Services

Bottom up Testing Pyramid

Functional / Non Functional Testing

QA benefits with Containers

Canary releases & role of container QA

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Understanding the Topic

3 Principles of DevOps Microservices Containers

Service

Small Autonomous

Choice of Technology

Independent deployment

Traditional

Micro Services

One Block

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Velocity Variation Visualization

Services Vs. Micro services

Autonomous

Decentralized

Independently Scalable

Technology Diversity

Loosely coupled

Characteristics

• Services are independent, cater to be new projects

and language agnostic

• Bits of code comprise services and are loosely

packed

• Intercom via API, specifically by a REST service

Shortcomings

• Service monitoring adds to overheads

• Tracking service failures is a painstaking job

• API calls are sometimes more of an overhead than the monolith intercommunication

Traditional Services

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Micro Services

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Layers of Testing in Micro services

Verify interactions at the boundary of an external service asserting that it meets the contract expected by a consuming service.

Verify that a system meets external requirements and achieves its goals, testing the entire system, from end to end.

Exercise the smallest pieces of testable software in the application to determine whether they behave as expected.

GUI Layer

Limit the scope of the exercised software to a portion of the system under test, manipulating the system through internal code interfaces and using test doubles to isolate the code under test from other components.

E2E

Contract Test

Integrated Systems Test

Unit Test

Component Test[Out Process & In Process]

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Microservice – Functional Testing at various layers

Unit Testing

• Core unit level functionality testing

• Test the lowest level of code

Component Testing

• Full functionality testing of service

• Similar to White box testing

Contract Testing

• Test the contracts the are agreed with other

components/services

• Interactions are verified at the boundary

Integrated Systems Testing

• Data flows, communication paths, Interactions

among microservices

• Integrations code, Protocol level issues

End to End Testing

• Full-fledged testing by covering the overall application in test, infrastructure related items such as firewalls,

proxies, load balancer

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Microservice – Non Functional Testing

Performance Testing

• Individual microservices need to be tested as

per the desired levels

• System wide performance testing

Session Management & Cache Testing

• Session handling across the Microservices

• Caching at the Microservice & system level

Fail Over and Recovery Testing

• Build a strategy for fail over and recovery of

individual services & test the same

Load Balancing Testing

• Ensure that the containers are instantiated and

load balanced as per the design (Prod)

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Parallel Testing with Microservices

Contract Tests

Deployto Test

Contract Tests

Contract Tests

Component Test

QualityScan

(Sonar)

UnitTest

BuildDeployto Dev

Contract Tests

Deployto Prod

Deployto Test

Contract Tests

E2E Tests

Contract Tests

Component Test

QualityScan

(Sonar)

UnitTest

BuildDeployto Dev

Contract Tests

Deployto Test

Contract Tests

Contract Tests

Component Test

QualityScan

(Sonar)

UnitTest

BuildDeployto Dev

Contract Tests

Deployto Test

Contract Tests

Integrated Systems

TestContract Tests

Component Test

QualityScan

(Sonar)

UnitTest

BuildDeployto Dev

Serv

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1Se

rvic

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Serv

ice

2Se

rvic

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QG1: Unit Test, Code Coverage ,Static Analysis for critical and major violations

– Warning ThresholdQG2: Contract Test QG3: Contract Test , Static Analysis for critical and major violations

– Error ThresholdQG4: Contract TestQG5: Integration Execution status & Test cases in passed state

Any open Critical or major defectsQG6: E2E Execution status & Test cases in passed state

– Any open Critical or major defects

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What is a Container

A Technology Problem A Shipping Industry Problem A Shipping Industry Solution

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Container/ Docker in Pictures – Virtual Machine Vs Container

Virtual Machines Containers

• Containers are an abstraction at the app layer that packages code and dependencies together.

• Multiple containers can run on the same machine and share the OS kernel with other containers, each running as isolated processes in user space.

• Containers take up less space than VMs (container images are typically tens of MBs in size), and start almost instantly.

• Virtual machines (VMs) are an abstraction of physical hardware turning one server into many servers.

• The hypervisor allows multiple VMs to run on a single machine.

• Each VM includes a full copy of an operating system, one or more apps, necessary binaries and libraries -taking up tens of GBs. VMs can also be slow to boot.

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QA Benefits of Containers

Ease of creating QA environments

• Ability to create and terminate containers at

will helps QA teams to bring up Test

Environment with ease

Run more tests and Test faster`

• Parallel tests can be executed on multiple

containers in the test environment

Improved confidence in the production system

• Lesser environment/configuration mismatch

issues

• Improved confidence in the production system

Run testing in environment with slight variation

• Maintain & Test multiple environments with

slight variation depending on the need

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Canary Release – Container Advantages

Canary Release - Fail Fast to Amplify Feedback

Canary release is a technique to reduce the risk of introducing a new software version in production by slowly rolling out

the change to a small subset of users before rolling it out to the entire infrastructure and making it available to everybody.

When running multiple versions of an application, one needs a quickly way to create copies of the application and make

configuration changes. This is possible with containers, as they can be spun up in seconds, and abstract away the

application from the operating system. Container is ideal for powering canary releases and testing them with confidence.

Blue Green Deployments

Canary Release

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References & Appendix

1. https://en.wikipedia.org/wiki/Microservices

2. https://en.wikipedia.org/wiki/Docker_(software)

3. https://en.wikipedia.org/wiki/DevOps

4. https://www.docker.com

5. https://martinfowler.com/bliki/CanaryRelease.html

6. https://martinfowler.com/articles/microservices.html

7. https://www.slideshare.net/jpetazzo/introduction-docker-linux-containers-lxc

8. http://blog.christianposta.com/deploy/blue-green-deployments-a-b-testing-and-canary-releases/

9. https://spring.io/blog/2015/07/14/microservices-with-spring

10. https://dzone.com/articles/microservices-basics

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Author Biography

Meghashyam Varanasi has about 15 years of experience in IT and ITes

industry. He holds an MBA from IIM Ahmedabad & B.Tech Computer

science degree. He is also AWS, PMP, ITIL certified besides few other

technology and domain certifications. Over the years he has been working

in solving various customer problems in the technology leadership space.

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Q&A