Distributed System: Lecture 5

Distributed System: Lecture

₅

Box Leangsuksun

SWECO Endowed Professor, Computer Science

Louisiana Tech University

[email protected]

CTO, PB Tech International Inc.

Operating System Concepts!

Box’s 1 minute Bio!

•  PhD in CS (1995): !

–  PhD Thesis: Resource management/allocation in Heterogeneous Parallel Distributed Computing!

•  7 years in industry labs (Bell-Labs, Lucent Technologies)!

–  Highly Reliable Software/system (IN, Service Management)! –  Architect, PM, Tech lead (15-30 team size)!

–  R&D -> 4 major network management products!

•  Associate Professor in CS since 2002.!

–  15 graduate students (4 PhD)!

•  Research Interest!

–  Cluster computing, Fault Tolerance OS/Runtime, Reliability , Availability and Serviceability and Security (RASS) in HPC/HEC, Software Engineering!

•  Services!

–  IEEE Cluster Computing Program committee member 2004-2005! –  A founder and CO-Chair: High Availability and Performance

Computing 2003-2004!

–  2003 Outstanding Teach Award, COES, Louisiana Tech U.! –  Creator of www.searchkatrina.org !

Cloud Computing

•  Intro to Cloud Computing & Concepts •  Amazon AWS

•  Expereinces in cloud app evaluation, research and development

Cloud Computing: Intro

Box Leangsuksun

SWECO Endowed Professor, Computer Science

Louisiana Tech University

- What is cloud computing?

- Characteristics of cloud computing

- Advantages and Disadvantages of cloud Computing. - Cloud Computing service models

- Cloud Computing deployment Model - Cloud Computing Concerns

- Conclusion

What is Cloud Computing?

•  - Every cloud vendor have their own definition

of cloud.

•  In General, Cloud computing is a Internet based

computing where hardware resources and

software are exposed as a services.

Internet vs Cloud

What is Cloud Computing?

•  These Services are exposed in a scalable manner

so that the user can use those services and pay for

only those services that are used.

•  as on demand computing just like to get electricity

we plug wire into socket.

•  - According to the survey by IDC between 2008

and 2010, the main reason to adopt a cloud

computing for the organization is low cost option

Cloud Definition in the eyes of

service provider

•  Technology aspects

•  Data Center – computing, networking & storage as well as application

•  Manage pools of resources

•  Virtualization and provisioning •  Monitoring & Accounting

•  All typical well managed Data center admin jobs

Cloud computing takes

virtualization to the next step

•

  You don’t have to own the hardware

•  You “rent” it as needed from a cloud

•  There are public clouds

– e.g. Amazon EC2, and now many others (Microsoft, IBM, Sun, and others ...)

•  A company can create a private one

– With more control over security, etc.

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Goal 1 – Cost Control

•  Cost

– Many systems have variable demands

•  Batch processing (e.g. New York Times) •  Web sites with peaks (e.g. Forbes)

•  Startups with unknown demand (e.g. the Cash

for Clunkers program)

– Reduce risk

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Goal 2 - Business Agility

•  More than scalability - elasticity!

– Ely Lilly in rapidly changing health care business

•  Used to take 3 - 4 months to give a department a server cluster, then they would hoard it!

– Using EC2, about 5 minutes!

•  And they give it back when they are done!

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Goal 3 - Stick to Our Business

•  Most companies don't WANT to do system administration

–  Forbes says:

•  We are is a publishing company, not a software company

•  But beware:

–  Do you really save much on sys admin?

–  You don't have the hardware, but you still need to

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5 Essential Cloud Characteristics

•  On-demand self-service •  Broad network access •  Resource pooling

–  Location independence

•  Rapid elasticity

- On demand Service

It allows organizations or users to get the computing resources they

need to run a application without having to go through different vendors that provide a services.

- Resource Pooling

Cloud computing allows pooling of computing resources to serve many consumers. Cloud providers resource are pooled to serve many customer using multitenant model, in which provider physical and virtual resources are assigned and reassigned according to the users demand.

Rapid Elasticity

The ability to expand and contract services on need basis is a key feature of the cloud computing. Cloud computing provides a resources like storage, servers and networking on demand means that if organization demand grows it can match its capacity to its demand.

- Broad Network Access

Traditional software’s were client based software like Open Office, Microsoft office were user have to install and upgrade their software in order to use it. User cannot access to the software if they are away from the system.

Pay Per Use

Cloud computing is a utility computing. Users pay for only what they have used and therefore use are charged on consumption based model.

- Scalability

- Cost Saving

- Business Agility

- Build in disaster recovery and back-up sites - Greener

- Security

- Data Location and recovery

- Internet dependency, performance and latency - Availability

- Current Enterprise application is difficult to migrate

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3 Cloud Service Models

•  Cloud Software as a Service (SaaS)

–  Use provider’s applications over a network

•  Cloud Platform as a Service (PaaS)

–  Deploy customer-created applications to a cloud

•  Cloud Infrastructure as a Service (IaaS)

–  Rent processing, storage, network capacity, and other fundamental computing resources

•  To be considered “cloud” they must be deployed on top of cloud infrastructure that has the key

Software as a service (SaaS)

- Software as a service (SaaS) also referred as software on demand, web based software or on demand software try to replace the application running on PC.

- In a simple term we are simply renting a software instead of buying it.

- The key providers are SaleForce.com, Google office application, Microsoft office 365, SAP HR.

Platform as a service (PaaS)

- Platform as a service (PaaS) provides a application development environment to user as a service by a cloud vendor.

- The consumer/developer can use this platform to develop application. - Cloud vendor is responsible for handling and managing the

infrastructure.

- Tradition model for developing and deploying a large application is complex and expensive.

- The key providers are Microsoft Azure Services Platform, Google App Engine.

Infrastructure as a Service(IaaS)

- Infrastructure as service provide a computing infrastructure to the user as service by a cloud vendor, sometime is also refereed as Hardware as a service (HaaS).

- Virtualization technique plays major role to make Infrastructure as a service reality.

- The user do not manage or control the underlying cloud infrastructure but has control over operating systems, storage, deployed applications, and possibly limited control of select networking components.

- The Key Provider are The Amazon Elastic Compute Cloud (Amazon EC2) ServePath’s(GoGrid), the Rackspace Cloud , the IBM Smart Business cloud solutions, Oracle Cloud Computing , GigaSpaces , RightScale and Nimbus .

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Service Model Architectures

Cloud Infrastructure IaaS

PaaS SaaS

Infrastructure as a Service (IaaS) Architectures

Platform as a Service (PaaS) Architectures Software as a Service (SaaS) Architectures Cloud Infrastructure SaaS Cloud Infrastructure PaaS SaaS Cloud Infrastructure IaaS PaaS Cloud Infrastructure PaaS Cloud Infrastructure IaaS

Various service models &

responsibilities

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4 Cloud Deployment Models

•  Private cloud

–  enterprise owned or leased

•  Community cloud

–  shared infrastructure for specific community

•  Public cloud

–  Sold to the public, mega-scale infrastructure

•  Hybrid cloud

Public Cloud

- The cloud infrastructure is available to the general public, it represent a cloud service that are openly accessible to the public.

- One of the key features of a public cloud is that all user for particular public cloud share the same infrastructure pool with different configuration and security configuration.

- Major player are Salesforce, Google, Microsoft, Amazon, Yahoo, Rack space and Zoho.

Private Clouds

- Private is also called internal cloud.

- It gives access to the cloud services for users who belong to the same organization that owns the cloud.

- Private cloud generally reside behind the firewall of the organization to provide a organization more control over the security policies.

- The disadvantage with this model is that is it is expensive to build and maintain a private cloud than access public cloud, therefore private cloud brings a larger cost and responsibility.

Hybrid Clouds

- Hybrid Clouds takes the benefits of both the public and private cloud models.

- It is combination of two or more clouds (public, private) that are unique but are tie together by standard technology (bridge) that allows them for application and data portability.

Comparison: Pros & Cons

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Amazon AWS

Give out mini project homework

1.  Going thru this tutorial “Getting Started with Linux Web Applications in the AWS Cloud”,

http://aws.amazon.com/web-applications/gsg-webapps-linux/.

2.  Create your AWS account and then follow each step in the above to create your own instances. Capture your screenshots to show what you do.

MS Azure

Google Clouds

Sample of comparisons

5/12/14

Cloud computing security

Requirements

Where ‘X ‘ denoting a mandatory requirement and ‘*’ optional requirement

Technologies behind the cloud

•  User side

–  Browser or access devices/APP –  Connectivity (internet)

•  Examples

–  Google docs.. –  Hotmail or gmail –  Dropbox

–  Amazon AWS (console interface)

Technologies behind the cloud

•  Provider side

–  Connectivity (internet)

–  Hardwares (server farm, storage, web) –  Infarstructure (data center)

–  Application Platform –  Virtualizations

–  Reliability Avialabilty Serviceabilty + Security –  Support Personal

–  Accouting

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Foundational Elements

of Cloud Computing

•  Virtualization •  Grid technology •  Service Oriented Architectures •  Distributed Computing •  Broadband Networks •  Browser as a platform •  Free and Open Source

Software •  Autonomic Systems •  Web 2.0 •  Web application frameworks •  Service Level Agreements

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Web 2.0

•  Is not a standard but an evolution in using the WWW •  “Don’t fight the Internet” – CEO Google, Eric Schmidt •  Web 2.0 is the trend of using the full potential of the

web

–  Viewing the Internet as a computing platform

–  Running interactive applications through a web browser –  Leveraging interconnectivity and mobility of devices

–  The “long tail” (profits in selling specialized small market goods)

–  Enhanced effectiveness with greater human participation

•  Tim O'Reilly: “Web 2.0 is the business revolution in the computer industry caused by the move to the

Internet as a platform, and an attempt to understand the rules for success on that new platform.”

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Software as a Service (SaaS)

•  SaaS is hosting applications on the Internet as a service (both consumer and enterprise)

•  Jon Williams, CTO of Kaplan Test Prep on SaaS

–  “I love the fact that I don't need to deal with servers, staging, version maintenance, security, performance”

•  Eric Knorr with Computerworld says that “[there is an] increasing desperation on the part of IT to

minimize application deployment and maintenance hassles”

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Three Features of

Mature SaaS Applications

•  Scalable

–  Handle growing amounts of work in a graceful manner

•  Multi-tenancy

–  One application instance may be serving hundreds of companies

–  Opposite of multi-instance where each customer is provisioned their own server running one instance

•  Metadata driven configurability

–  Instead of customizing the application for a customer

(requiring code changes), one allows the user to configure the application through metadata

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SaaS Maturity Levels

•  Level 1: Ad-Hoc/Custom •  Level 2: Configurable •  Level 3: Configurable, Multi-Tenant-Efficient •  Level 4: Scalable, Configurable, Multi-Tenant-Efficient 46

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Utility Computing

•  “Computing may someday be organized as a

public utility” - John McCarthy, MIT Centennial in 1961

•  Huge computational and storage capabilities available from utilities

•  Metered billing (pay for what you use)

•  Simple to use interface to access the capability (e.g., plugging into an outlet)

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Service Level Agreements

(SLAs)

•  Contract between customers and service

providers of the level of service to be provided •  Contains performance metrics (e.g., uptime,

throughput, response time) •  Problem management details

•  Documented security capabilities

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Autonomic System Computing

•  Complex computing systems that manage themselves •  Decreased need for human administrators to perform

lower level tasks

•  Autonomic properties: Purposeful, Automatic, Adaptive, Aware

•  IBM’s 4 properties: self-healing, self-configuration, self-optimization, and self-protection

IT labor costs are 18 times that of equipment costs.

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Grid Computing

•  Distributed parallel processing across a network •  Key concept: “the ability to negotiate

resource-sharing arrangements”

•  Characteristics of grid computing

–  Coordinates independent resources –  Uses open standards and interfaces –  Quality of service

–  Allows for heterogeneity of computers

–  Distribution across large geographical boundaries –  Loose coupling of computers

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Web Services

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•  Web Services

–  Self-describing and stateless modules that perform discrete units of work and are available over the network

–  “Web service providers offer APIs that enable developers to exploit functionality over the Internet, rather than delivering full-blown applications.” - Infoworld

–  Standards based interfaces (WS-I Basic Profile)

•  e.g., SOAP, WSDL, WS-Security

•  Enabling state: WS-Transaction, Choreography

–  Many loosely coupled interacting modules form a single logical system (e.g., legos)

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Service Oriented Architectures

•  Service Oriented Architectures

–  Model for using web services

•  service requestors, service registry, service providers

–  Use of web services to compose complex, customizable, distributed applications

–  Encapsulate legacy applications

–  Organize stovepiped applications into collective integrated services

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Web application frameworks

•  Coding frameworks for enabling dynamic web sites

–  Streamline web and DB related programming operations (e.g., web services support)

–  Creation of Web 2.0 applications

•  Supported by most major software languages •  Example capabilities

–  Separation of business logic from the user interface (e.g., Model-view-controller architecture)

–  Authentication, Authorization, and Role Based Access Control (RBAC)

–  Unified APIs for SQL DB interactions –  Session management

–  URL mapping

•  Wikipedia maintains a list of web application frameworks

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Free and Open Source Software

•  External ‘mega-clouds’ must focus on using their massive scale to reduce costs

•  Usually use free software

–  Proven adequate for cloud deployments –  Open source

–  Owned by provider

•  Need to keep per server cost low

–  Simple commodity hardware

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Platform Virtualization

•  “[Cloud computing] relies on separating your

applications from the underlying infrastructure” - Steve Herrod, CTO at VMware

•  Host operating system provides an abstraction layer for running virtual guest OSs

•  Key is the “hypervisor” or “virtual machine monitor”

–  Enables guest OSs to run in isolation of other OSs –  Run multiple types of OSs

•  Increases utilization of physical servers

•  Enables portability of virtual servers between physical servers

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The Traditional Server Concept

•  Pros

–  Easy to conceptualize –  Fairly easy to deploy –  Easy to backup

–  Virtually any application/

service can be run from this type of setup

•  Cons

–  Expensive to acquire and maintain hardware

–  Not very scalable –  Difficult to replicate

–  Redundancy is difficult to implement

–  Vulnerable to hardware outages

–  In many cases, processor is under-utilized

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The Virtual Server Concept

Virtual Machine Monitor (VMM) layer between Guest OS and hardware

Virtualization: Key concepts

• Virtual Machine (VM), guest OS: complete operating system running in a virtual environment

• Host OS: operating system running on top the

hardware, interface between the user and the VMM and VMs

• Virtual Machine Monitor (VMM):, Hypervisor: manage VMs (scheduling, hardware access)

Virtualization: Usage

Ø Server consolidation Ø  Software testing

Ø  Security, Isolation

Ø  Lower cost of ownership of server. Ø  Increase manageability

Different Virtualization Concepts

•  Full-virtualization: full virtual machine, from the boot sequence to the virtualized hardware

•  Para-virtualization: the guest OS has to be modify for performance optimization

•  Emulation: the guest OS architecture is different

from the architecture of the host OS (translation on the fly). Ex: PPC VM on top of a x86 host OS.

Classification

•  Two kinds of system virtualization

–  Type-I: the virtual machine monitor and the virtual machine run directly on top of the hardware,

–  Type-II: the virtual machine monitor and the virtual machine run on top of the host OS

Hardware Host OS VMM VM VM Hardware VMM Host OS VM VM

Available Solutions

•  Example of Virtualization Projects

–  Type I: Xen, L4

–  Type II: VMWare, Qemu

•  Different Benefits

–  Type I: performances

•  direct access to the hardware simple to implement •  para-virtualization possible

–  Type II: development

•  no limitation of para-virtualization •  emulation possible

Case Studies

Suppose you are Forbes.com

•  You offer on-line real time stock market

data

•  Why pay for capacity weekends, overnight? 20090909_VirtualizationAndCloud 64 9 AM - 5 PM, M-F ALL OTHER TIMES Rate of Server Accesses

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Forbes' Solution

•  Host the web site in Amazon's EC2 Elastic

Compute Cloud

•  Provision new servers every day, and deprovision them every night

•  Pay just $0.10* per server per hour

–  * more for higher capacity servers

Eucalyptus

- Elastic Utility Computing Architecture for Linking Your Programs to useful systems.

- It is an open-source software for implementing 'cloud computing' on clusters. - It is webservice based cloud computing infrastructure.

- The current interface to Eucalyptus is compatible with Amazon's EC2 interface, but the infrastructure is designed to support multiple client-side interfaces.

- Eucalyptus helps to set up a cloud platform, which then can be offered as a service, either publicly or internally.

Microsoft Azure Cloud PaaS

Azure Goals

ü  Familiar tools, languages, and frameworks with .NET and Visual Studio ü  Provides the choice to build on-premises, cloud, or hybrid solutions ü  Integrate with existing assets such as AD and premises applications ü  Multiple protocol support including HTTP, REST, SOAP, AtomPub

ü  Broad investment in open, community-based access to Azure services ü  Simple scenarios are simple – complex scenarios are possible

ü  Services hosted in Microsoft’s data centers ü  Designed for high availability & scalability

What does Azure platform offer to

developers?

Amazon Cloud

Comparison: open vs closed

sources in platform-as-a-Service

Comparison: open vs closed

sources in IaSS

The NIST Cloud Definition

Framework

81 Community Cloud Private

Cloud Public Cloud

Hybrid Clouds Deployment Models Service Models Essential Characteristics Common Characteristics Software as a Service (SaaS) Platform as a Service (PaaS) Infrastructure as a Service (IaaS) Resource Pooling

Broad Network Access Rapid Elasticity Measured Service On Demand Self-Service

Low Cost Software

Virtualization Service Orientation Advanced Security Homogeneity

Massive Scale Resilient Computing Geographic Distribution

Conclusion

- Cloud computing is the promising technology where hardware resources and software are exposed as a services in a scalable manner so that the user can use those services and pay for only those services that are used.

- Cloud computing is not a silver bullet technology, we should make decision on a project by project basis and should be on the nature of the application or data that is being supported.

- Some Disadvantage such as security risks.

- Cloud computing has a potential to be a disruptive technology that may change how the IT business is done.

Cloud Computing In Reality: Experience

sharing in cloud solution developments and

evaluations

Cloud Computing In Reality: Experience sharing in cloud solution developments and evaluations

•  The talk presents recent experiences in evaluating cloud & other solutions and making decisions towards cloud

services. The speaker will discuss requirements aspects of his medical applications and another R&D project as well as why his decision was made and based on technical and

business facts.

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Dilbert on cloud J

Outline

v  Background & Motivation

v  Cloud-based Medical Service Application

v  Architecture decision & Amazon AWS

v  Summary

BACKGROUND & MOTIVATION

Opportunities

•  EKG Services – Medical Application for startup

•  Technical Evaluations for

Cost-based Disaster Recovery Solution R&D (next talk)

Decisions, Decisions??(1)

•  Medical data is vital, especially in intesive care •  Data & System/Infrastructure are quite Critical •  Must be always available

•  Cost

•  Pay Per Usage

Decisions, Decisions?? (2)

•  Time to Market

•  Guaranteed Reliability, Availability & Performance •  Stick to your busines

•  Must be profitable

•  Hosted Servers, Private or Public CLOUD

EKG SERVICES

Credit: picture from nih.gov

EKG - Electrocardiography

•  A medical test that checks for problems with the electrical activity of your heart

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EKG Services- Smart Health

•  Requirements

•  Mobility – wireless

•  Smarter – data warehouse & data analytics •  As Reliable

•  Service-based or subscription-based •  Cost Effective

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EKG Services- possible

technologies

•  Embedded system – electronics

•  Wireless Technologies – wifi, bluetooth •  Web/Client-Servers (SOA) – web services

•  Service-based Separation of infrastructure –

Virtualization/cloud computing

•  Smart health – data analytic or hadoop

System Architecture

! 95

cloud

Client Device/App

! 96

The View

!

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Smartness – server based decisions

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Pros & Cons on the server

architecture

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1-Tier 2-Tier Multi-Tier

Benefits Very simple

Inexpensive No server needed Good security More scalable Faster execution Exceptional securityFastest execution “Thin” client Very scalable

Issues Poor security

Multi user issues More costly More complex “Thick” client Very costly Very complex

Users Usually 1 (or a

few) 2-100 50-2000 (+)

Architectue Decisions

•  Multi-tier SOA architecture (3-tier)

•  Anticipated fast growth, elasticity & guaranteed Reliability with Auto-scaling

•  Smart health data analytic •  Cost Factor & Pay per usage

•  Cloud-based compute (VM) & storage/DB

•  Public cloud - Amazon EC2 & RDS

Solutions

Amazon Cloud Services

•  Elastic Compute Cloud – EC2 (IaaS) •  Aamzon RDS (Database)

•  Elastic Block Storage – EBS (IaaS) •  SimpleDB (SDB) (PaaS)

•  Simple Queue Service – SQS (PaaS) •  Elastic Load Balancing (ELB)

•  Consistent AWS Web Services API & AMI

Cloud-based EKG service

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RDS

hadoop

EKG app server Web + app server On EC2 instance

Cloud-based EKG service

(alternative)

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RDS

hadoop

EKG app server

Web serve

r

Is amazon cloud the right choice?

•  When compared to host your own infrastructure.

•  Cost is a major & obvious factor beside to focus on your business.

–  Server cost ($10-20K/server for HA)

–  Admin staffs (e.g. $100,000 – $150,000/ year FTE) –  Data center ($300/ft2, build or rent??)

–  Operational cost (electric/cooling, $23,000/kW) –  Cost of downtime and lost data

Example Amazon EC2 Pricing

Example Amazon RDS Pricing

•  We make the same assumption:(Micro, 10 hours pre day)

•  One year cost will be : 23$ + 0.016*12*365=93.08$

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Scaling & Reliability

•  Nothing is for free but possible

•  Using AWS Elastic Load Balancing •  Auto-Scaling with CloudWatch

•  Require the right design, configurations and developments

The Right Cloud App

•  Design & build cloud app.. Don’t just build app in the cloud

•  Design for failure anticipation

•  Best Practices in design scalability •  Design for dynamism

•  Use cloud standard API & cloud features •  Build Security into every component

Design & build cloud app

•  Use self-discovery, be self configurable, and network independent •  Use cloud standardized Messaging & DB when possible

•  Leverage inherent EBS replication and snapshots for DBMS

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Design with failure anticipation

•  Avoid single point of failure

•  Use multiple AWS zones (EC2 can fail, zone can be unavailable)

•  Use Elastic IP addresses

•  Create multiple DBMS slaves across Availability Zones

•  Use Amazon CloudWatch for real-time monitoring

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Design Scalability

•  No central point of data storage contention •  Use Load Balancing such as ELB

•  Use Auto-scaling

•  Design cloud app servers that are loosely coupled with self-discovery

•  Use Amazon CloudWatch for realtime monitoring

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Conclusion

•  Cloud architecture seems to be the right choice for startup (e.g. EKG smart health service)

•  When no predetermined or guaranteed workload or customers, pay per usage is more logical and cost-effectives

•  Nothing for free.. So design and build cloud application not just build your app on cloud •  Stick to your BUSINESS