Cloud Computing

Topics

1. What is the Cloud?2. What is Cloud Computing?3. Cloud Service Architectures4. History of Cloud Computing5. Advantages of Cloud Computing6. Disadvantages of Cloud Computing7. Cloud Deployment Architectures

Images courtesy of Majd F. Sakr or from Wikipedia unless otherwise noted.

What is the Cloud?• The term cloud comes from the cloud

icon used in network diagrams.• Today the cloud is a large set of hardware

and software hosted in a data center provided as a utility computing service.

What is Cloud Computing?

“Cloud computing is a model for enabling convenient, on-demand network access to a shared pool of configurable computing resources (e.g., networks, servers, storage, applications, and services) that can be rapidly provisioned and released with minimal management effort or service provider interaction.”

NIST definition of Cloud Computing

Cloud Service Architectures

Software as a Service (SaaS)– Web-accessible applications

Platform as a Service (PaaS)– Platform for custom software development

Infrastructure as a Service (IaaS)– Virtual machines, storage, and networks

Cloud Service Architectures as Layers

Cloud Service Architectures by User

Cloud Service Models Abstraction Layers

Cloud Service Models form a Continuum

http://cs.jhu.edu/~ragib/sp10/cs412/

Software as a Service

Clients use provider’s applications running on cloud infrastructure via the web. Client can configure application, but not network, OS, storage, etc.

SaaS Architectures

Platform as a Service

Clients can deploy client-developed or acquired applications that were created using programming tools and languages supported by provider.

Infrastructure as a Service

Client can provision processing, storage, networks, and other basic computing resources on which the client can run arbitrary software.

IaaS enabled by Virtualization

• Allows easy sharing of hardware resources.• Produces higher utilization rates.

IaaS enabled by Virtualization

Linux BSD W2k8

PhysicalMachine

VirtualMachines

History of Cloud Computing

Douglas Parkhill, 1966

Evolution of Cloud Computing

Nellutla and Teoh, IBM, 2008

Why Cloud Computing Now?

• Data-intensive Applications• Data Center Complexity and Cost• Increase Network Capacity and Availability• Rising Energy Costs

Cloud Computing Advantages

• Flexibility• Scalability• Cost• Maintenance• Utilization• Power

Flexibility

Software: any platformAccess: access from any host on InternetSpeed: Deploy infrastructure quickly

Scalability

Controlled via softwareNo time required to purchase, delivery, install hardwareAdd or remove resources almost instantly

Can scale up and down to meet demandIllusion: unlimited resources available on demand

Cost

Pay-as-you-go modelNo capital expendituresSmall companies can tap high end infrastructure

Maintenance

Maintenance responsibility of cloud provider– IaaS: hardware, network– PaaS: software stack, OS, hardware, network– SaaS: everything

Can use to reduce size of IT department

Utilization

Typical DC utilization around 20%

– Must have enough capacity for peak usage times

Different customers have different usage patterns

Power

Lower power consumptionConsolidation of serversVirtualization increases usageLarge scale highly efficient DCs

Lower power costsDCs built near cheap

power sources

Cloud Computing Disadvantages

• Security• Privacy• Vendor lock-in• Migration

Security

• Third party stores organization data so• Attackers can target communications between

cloud provider and client• Attackers can target cloud provider directly

http://www.cert.ge/

Privacy

• Cloud providers can monitor communications between client and provider

• Cloud providers can read client’s data if it is not always encrypted

• Privacy protections depend on location and you may not know where your data is located

Vendor Lock-In

• Most cloud APIs are proprietary• Cloud providers offer different features• It can take weeks to move data out of a cloud

Migration

• Systems already need to be consolidated and ready to be virtualization before migration

• Slow WAN speeds lead to slow migrations

Cloud Deployment Architectures

Cloud Deployment Architectures

Public Clouds

• Cloud is located off-site• Third party provider owns and maintains• Pay as you go service

Private Clouds

Community Cloud

Hybrid Clouds• Combined cloud environment with multiple internal

and/or external providers.• May automatically use public cloud resources when

private cloud resources are used at full capacity.

http://www.acutesys.com/?page_id=63

Key Points

• Cloud computing definitions• Cloud service architectures

– Software as a Service (SaaS)– Platform as a Service (PaaS)– Infrastructure as a Service (IaaS)

• Advantages and disadvantages of cloud computing• Cloud deployment architectures

– Public– Private– Community– Hybrid