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Define cloud

  • On Demand

  • Scalable

  • Multi-Tenant
  • Self service
  • Reliability
  • Utility Based Subscription

Public cloud

Providers let clients access the cloud via Internet Made available to the general public

Private cloud

The cloud is used solely by an organization (e.g. HKUST, Facebook, HSBC)

May reside in-house or off-premise

  • Secure, dedicated infrastructure with the benefits of on-demand provisioning

  • Not burdened by network bandwidth and availability issues and security threats associated with public clouds.

  • Greater control, security, and resilience.

Hybrid cloud

Composed of multiple clouds (private, public, etc.) that remain independent entities, but interoperate using standard or proprietary protocols

Banks, hospitals, government

Infrastructure-as-a-Service

  • Providers give you the computing infrastructure made available as a service. You get “bare-metal” machines.

  • Providers manage a large pool of resources, and use virtualization to dynamically allocate

  • Customers “rent” these physical resources to customize their own infrastructure

  • Full control of OS, storage, applications, and some networking components (e.g., firewalls)

IaaS

Netflix rents thousands of servers, terabytes of storage from Amazon Web Services (AWS)

Develop and deploy specialized software for transcoding, storage, streaming, analytics, etc. on top of it

Is able to support tens of millions of connected devices, used by 40+ million users from 40+ countries

  • Example: Amazon EC2

Platform-as-a-service PaaS

Providers give you a software platform, or middleware, where applications run

You develop and maintain and deploy your own software on top of the platform

The hardware needed for running the software is automatically managed by the platform. You can’t explicitly ask for resources.

  • Example: AWS lambda

SaaS

Providers give you a piece of software/application. They take care of updating, and maintaining it.

You simply use the software through the Internet.

  • Example: Office 365

Why the cloud

  • Pay only for what you use Easy/fast deployment to end users

  • Monthly payments

  • Encourages standard systems

  • Requires less in-house staff, costs

Virtual Machines

  • Infrastructure as a Service (IaaS)

  • Provides an operating system, storage, and networking

  • User needs to maintain the software on the VM

Virtualization

  • Virtualization is an enabling technology for IaaS Cloud

  • Suppose an IaaS provider owns a large cluster and wants to provision cloud services for its users

  • Virtualization is a broad term. It can be applied to all types of resources (CPU, memory, network, etc.)

  • Allows one computer to “look like” multiple computers, doing multiple jobs, by sharing the resources of a single machine across multiple environments.

Old model:

A server for every application. Big disadvantage: low utilization

New model:

Physical resources are virtualized. improved utilization

Resource pooling

The provider’s resources are pooled to serve consumers using a multi-tenant model, with different physical and virtual resources dynamically allocated according to consumer demand.

Location independence: the customer generally has no control or knowledge over the exact location of the provided resources but may be able to specify location at a higher level of abstraction (e.g., country, state, or datacenter).

Advantage for providers: efficiency in utilization