Cloud Computing

and

Software Engineering

Ravindra Dastikop http://dastikop.blogspot.in

View video of this presentation : http://youtube.com/user/dastikop

Purpose 

●Cloud represents at the same time a new emerging

opportunity and new challenge

●This presentation aims to identify the challenges

inherent to cloud applications and suggests some

approaches towards the same.

Agenda for Presentation

●What is a Cloud Application? (project) ●Cloud resources for cloud application

developers●Cloud application examples○General examples○Cloud applications (that our students have

built) ●A sample cloud Application demo●Q & A session ●Summary 

Evolution of Computer

Applications

Desktop Applications

Full control and ownership of machine, data, software

Web Application

No ownership, data stored elsewhere, application comes from service provider

Rich, remote and responsive (now)

Picture credit: http://wiki.sproutcore.com

Goal of Cloud Applications

●Cloud application represents the state of

art in application development

●They try to combine best of both worlds -

○richness of desktop with

○remoteness of web applications 

 

Cloud Application : Meaning

●Cloud computing applications are the applications available

as SaaS over the internet 

●which facilitates the user to run those applications without

installing them on his own computer. 

●This saves the cost of infrastructure and hardware

maintenance. 

● In general cloud computing customers do not own the

infrastructure but use it from a third party provider as a

service.

Cloud Application : Where do they come from?

●Cloud computing applications are loaded at the

server of service provider and the service provider

give access to these applications through an

interface using internet.

●Every customer has its own unique account from

which they log on to the cloud of the provider and

access the application they have paid for. 

●Service provider also provides space at his own

server for the customer’s data.

CloudApp : A Simple Example

CloudApp allows you to share as well as save files

easily on the web. It works well for links, images,

video and music. Check out how the entire thing

works-

●Select a file

●Drag the file to the menu bar

 CloudAPP

Any Questions?

Cloud Apps: The difference

Statelessness and server failures are givens in the cloud

The big difference between a traditional application and cloud application is that cloud application itself is able to provision the resources that the application needsUsing API’s applications for cloud can be designed so that they request more resources from the cloud provider

Cloud Apps: The difference

Cloud Applications have to be stateless

If cloud application has states, it becomes a challenge

In cloud if something dies, you kill it and reincarnate

There is no concept of a local disk, no registry

All these is encapsulated by being a stateless

application

Cloud Apps: The difference

Cloud applications need to be designed for

redundancy and should acknowledge that commodity

machines are being used in the cloud

It is a guarantee that machines are going to fail, hence

cloud application need to designed for redundancy

Cloud Apps: The difference

Cloud Apps parts can be scattered in many places

● Presentation layer might be on the Facebook storage could be on Amazon’s S3

● application logic could run somewhere else entirely

In traditional applications, entire application used to built on own servers

Building cloud application requires solid engineering and design

Cloud Apps: The difference

Database are not same in the cloud

Cloud databases are non-relational schema-free

Cloud Apps: The difference

Database are not same in the cloud

Example:

Google App Engine uses Google’s Big Table data store

for persistent storage. Big Table is not a SQL

database, and the reason for that is because some of

the functionalities supported by SQL databases - for

example- joins- make it very difficult to split a

database across multiple machines

Cloud Apps: The difference

Database are not same in the cloud

In cloud database using Big Table - denormalization

is encouraged from the design phase.

This enables developers to store data in multiple

places at the same time. As a consequence

applications run very efficient queries

Cloud Apps: The difference

Database are not same in the cloud

What developers have found that in very high-traffic

situations, relational databases are extremely

difficult to manage and that ends up being a huge

money and resource sink for developers

Cloud Apps: The difference

Get used to rapid change in the cloud

● Things change much more rapidly in the cloud.

● Cloud providers offer new releases several time a year

and each upgrade might have something a developer

wants to take advantage of

● A developer need to stay abreast of those developments,

keep eye on lot of the different blogs and also particpate

in webinars

Cloud Apps: The difference

Developer need to be aware of different design

patterns such as eventual consistency- in which a

change to an application might not register for a few

million seconds. The consequence of that is that you

can not utilize a database to keep track of the next

value “

This needs a different programming approach when

they are utilizing the cloud because of such things

Cloud Apps: The differenceDevelopers can let go most of plumbing concerns

in the Cloud

The loosely coupled nature of web makes it an easier

development platform.

Developers can focus on innovation and business logic

instead of worrying about plumbing and infrastructure such

as the operating system and hardware.

Cloud service providers offer security, workflow,

administration and load-balancing as seperate modules

Cloud Apps: The difference

One enterprise wanted to build college

admission applications on Microsoft’s .NET

platform but found that it was many times

cheaper to develop on Force-.com- this is

because of its use of pre-built functionality.

Any Questions?

Cloud Apps: The difference

Developers need to keep in mind the

difference between cloud platforms and

licensing models different cloud models have

different pricing models

Cloud Apps: The differenceDevelopers should develop applications in such a way

that they could be moved off that platform

For example, Google enables such mobility by

supporting the popular Python language and the

Django web framework and supports open source

uploading and downloading tools for moving data in

and out of GAE

Software engineering

Software engineering is the application of systematic,

disciplined, quantifiable approach to the development,

operation, and maintenance of software

Cloud computing offers new possibilities for

multilateral software

Cloud Apps: The differenceASPECT Traditional

Softwaremultilateral development (Cloud

Software Composition

coherent set of software modules

interoperable third party components

Cloud Apps: The differenceASPECT Traditional Software multilateral

development ( Cloud

source code

full source available no source code for third party companies

Cloud Apps: The differenceASPECT Traditional Software multilateral

development ( Cloud

execution model

single computer often distributed between multiple computeres

Cloud Apps: The differenceASPECT Traditional Software multilateral

development ( Cloud

Ownership and control

single team or enterprise

distributed between multiple enterr

Cloud Apps: ChallengesASPECT cloud computing Challenge

Source code

No source code for third party compoenents

system comprehension

Execution model

often distributed between multiple computers

state inspection and debugging

Ownership and control

distributed separation of ownership

Any Questions?

Cloud Apps: key principles

● The Map-Reduce paradigm for independent

computation

● schema-free databases and their use

● service-oriented computing

● multi-tenancy

● security and compliance

● design for resilience

● loosely-coupled

Cloud Apps: promises

● Reduced development time through use of

high-level service

● maximum utilization of resources: pay for

what u use

● reduced operation costs

● increased development productivity

●

Cloud Computing Resources

What is available for developers

Cloud Application Building ResourcesOpen source● Java● C# DotNet ● AJAX- real time collaboration● GAE- Google Application Engine ● PHP It provides web developers with a full suite of tools for

building dynamic websites● Python: integrate your systems more effectively ● API - Royal route resources Google APIs, ● Facebook

Commercial ● AWS - Amazon Web services● Microsoft Azure

Any Questions?

Developing a Cloud Application

Demonstration

Cloud applications using Open sources

Cloud Teaching System using

Google Application Engine(GAE)

(Our Final Year Project)

A Placed and Happy Student

My Maps Locator

developed using Google Map API

Challenge is customizing it for Mobile

A simple Cloud application

Examples- Business

Housing Maps Route Finder

Facebook Game

Deployed on AWS.

Fametown

Best ExampleTwitter

Cloud Application Using Open Source

Social site aggregator

usingFacebook

TwitterLinkedlin

( A Final Year Project )

CloudCourse: An Open source cloud application

CloudCourse is a course scheduling system. It is built on

GAE

CloudCourse

Cloud Applications using Open Source

AlumniMaps

Procures Facebook users data and Plots on Google

Uses Flex, Google Maps API, Facebook API

Final Year Project

A Happy Student

Training and Placement cell ( PES, Mandya

Training and Placement cell

using Google App Engine and Google APP Store

Virtualization Project ( NIE, Mysore)

Cloud Computing for SMES- BVB Students 

Cloud Computing for SMEs

First version of this project is done by a group of Hyderabad engineering students.

BVB gr oup is build it further on

FaceBook Applications

Developing a Facebook Application: First Step

Developing FB applications: Tools

Blog Post Translator Application Objective:

To translate Blog post in English to Different languages

Resource used

● Google App Engine- A Paas Solution● Google Translate API

● Language: Python

AWS Applications

Building Your First Cloud Application on AWS

MS in Software Engineering

To be Presented atRecent Advances in Web Technologies,

St.Joseph Engineering College, Mangalore,

27-29 Jan, 2011

Cloud Computing:Engineering Approach

click here to see updated version

Ravindra Dastikop

email : Ravindra.dastikop@gmail.com

http://dastikop.blogspot.com

Purpose

In this this presentation , we ●explain why cloud applications business

appeal ● list challenges encountered during

development of cloud scale applications●provide an introduction to newly emerging

discipline – Cloud Engineering●Share our experience of Cloud Engineering

http://dastikop.blogspot.com

Agenda for Presentation ●Challenges- Developing a cloud

application?●Cloud Engineering – Discipline for

develop cloud applications●Q & A●Summary

http://dastikop.blogspot.com

Emergence of Cloud Computing Age

●Cloud has become a preferred destination for enterprises to host applications

●Designing and building applications for the Cloud requires specialized skills

●It demands a new mind set and also architecrual thinking (MS)

Understanding Cloud Phenomenon

In order to understand Cloud Engineering, it is necessary to know about Cloud Computing and Cloud application. Please refer to the following presentations before u proceed further

●Cloud computing- Foundation of Cloud computing ●Cloud application- Fruits of Cloud Computing ●

The Challenge

Developing Cloud scale Applications

Cloud Application: An Example

The Cloud Evolution

CloudApp

allows something as fun and simple as sharing of images, links, music, videos and files by simple choosing a file and drag it to the menu bar to be easy, faster and reliable

by providing short link automatically copied to your clipboard that you can use to share your upload with co-workers and

friends.

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Why cloud-deployable applications?

●Cloud computing infrastructure is an interesting proposition because of its

●Pay-per-use model●Ability to leverage the benefits of platform

as a services.●Result: Cloud application is

○A major requirement (business)○A challenge for developers

How a FREE Cloud Application can become a business

Cloudapp Pro is available with more features and is now charged

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Challenges in Cloud Computing

● Number 1. Business Continuity and Service Availability● Number 2. Data Lock-In● Number 3. Data Confidentiality/Auditability● Number 4. Data Transfer Bottlenecks● Number 5. Performance Unpredictability● Number 6: Scalable Storage● Number 7: Bugs in Large-Scale Distributed Systems● Number 8: Scaling Quickly● Number 9: Reputation Fate Sharing● Number 10: Software Licensing

Source:

Cloud engineering- Business Reason

●Cloud services typically deliver commodity-like capabilities, often with consumer-grade service-level agreements, and organizations will be dealing with the inherent challenges in this business model

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Requirements of Cloud application

●High reliability ●Dynamic scalability

○Millions of users○Volumes of data

●Low latency●Across all layers

○Database○Messaging○Web

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Cloud EngineeringBuilding Cloud applications

Cloud Engineering

●Cloud Engineering is the process of designing the systems necessary to leverage the power and economics of cloud resources to solve business problems.

Cloud Engineering An Analogy

Comparing CE with Transportation engineering

Transportation engineering ( Golden Qudrangle

Transportation engineering

Build Roads

Transportation engineering

Build Vehicles ( Applications)

Transportation Engineering

Develop Standard Practices (Rules)

Cloud engineering Cycle

Source:

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TRADITIONAL APPROACH

1

2

3 4

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Engineering Perspective

Research and Practical challenges

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A cloud application: Ticketing System

●Describe the systems

Cloud Engineering : Simple definition

Cloud engineering is the process of designing systems to leverage cloud

architecture

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Challenge No 1: High ReliabilityServices without any disruption

●Vertical scaling○ Adding more CPUs and Disks○ Example: A Dating web site scaled up their application

to handle over a billion requests per month by moving to 512 GB RAM, 32 CPU Machine

○ Cost 100K USD ( costly high-end configuration ●Horizontal scaling

○ Second option is to use run application on commodity hardware, scaling horizontally by adding more box, as the need to scale up arose

●Moving application to cloud

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Applications scale up

●Scaling up must happen in all tiers – ○web, ○messaging and ○database

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Scaling Up database-1

●Databases are not built for scale●The primary factor for scaling up a database is

disk I/O performance●Vertical Scaling can be achieved by adding high-

end disks with greater speeds and replication●Affordable RAID 6 or RAID 10 disk can be used

to improve disk performance●RAID disks Upper limit on disk transfer speed is

200MBps to 1GBps- which limits scaling

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Scaling up of database –Option 2

●Adding more database instances with master-slave replication strategy where master handles writes, and replicates data to multiple slaves

●MySQL supports master-slave scale-out configuration where data gets replicated transparently to the slaves.

●When application spends most of the time in reads, the application scales as the reads can be served from any slaves

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Example- Master-slave

●Master-slave is deployed in Dekoh.com.●During user registration at Dekoh.com where all

new users sign-up requests, which involve write-to database, are routed to the master, and the login requests to slaves

●Since user login occurs frequently compared to user registration, the above configuration scales up well,

●Master does not scale when there are more writes and when it also adds a slave lag as the data gets replicated

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Sharding and De-normalization

●Portioning data across master would distribute writes to different instances and both the reads and writes scale well

●To achieve reliability replication should be used along with lesser number of slaves to overcome the slave lag

●Example: Flickr.com ○ Moved from pure replication to the Sharding

mechanism to be able to scale●Shading schemes – need changes in application

architecture

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The consequence of Sharding

●Portioning data into shards add more complexity in terms of maintaining the integrity of data, application architecture and Joins. ( ACID)

●Any change in the portioning scheme would require reorganizing the entire data which is expensive

●Joins are not possible as data is broken up into different shards. (Join demands data to be available on same memory space)

●Solution is to introduce some kind of de-normalization – (end of a cherished practice)

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De-normalization

●De-normalization is basically bringing , often redundant data together, to improve the query performance. (fundamental go for a toss)

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De-normalization – an example● One application has a message infrastructure where messages are

sent to recipients (users).● Messages are stored in “Message” Table and the “recipient” table

contains message to recipient mapping.● To obtain recent 10 messages sent to a particular recipient, all

messages-ids for recipient are obtained from the “recipient” table and a join is performed on the “message” table filtering the recent 10 timestamps.

● If there are lot of messages, sent to a particular recipient, a join is performed on the messages table with lot of rows from the “recipients” table and then the time stamp filter is applied.

● Instead, if the timestamp of the message is duplicated in the recipient table, it is easy to filter out the first 10 messages ids and then perform a join.

● With this approach the query takes lesser time to execute and minimize disk I/O

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Cloud Engineering by Google

● Google has come out with its own datastore implementation

● Google’s Bigtable is a distributed ‘scheme-less” key-value store, which was developed for the web search engine.

● It is applied to Orkut, Docs, Google Maps, Earth and others.

● Bigtable runs on the top of Google File System and provides the needed scalability at its core, supporting high availability at the file system level

● Google App Engine offers Bigtable as the primary datastore for application developers.

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Cloud Engineering by Amazon

● Amazon’s SimpleDB is a distributed key-value store which supports a SQL-like syntax for retrieving data and exposes REST API for all operations.

● SimpleDB is available as a paid service and is very effective when working with huge amount of data

● Limitations ● Restrictions imposed on size of results, comparisons,

predicates used in the query● No supports for transactions, aggregate functions, data

types and full-text search ● For above reasons, adoption of service is less.

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Cloud Engineering by Facebook

● Facebook uses Apache Hive● It is a data warehouse that runs on the top of the Hadoop

distributed system● Facebook uses Hive to analyze historical data of users

and content using brute force mechanism● Hive is not a datastore but is only used for analytics on

the large amounts of data.● The other datastore include

○ HBase○ Hypertable○ Cassandra○ CoudDB○ Voldermort

Contact Information

Ravindra DastikopAssistant Professor, CSE

SDM College of Engineering & TechnologyDharwad 580 002

email: ravindra.dastikop@gmail.com

web site: http://dastikop.blogspot.com