4.1 Summarize Cloud-Computing Concepts

  • Common Cloud Models
    • Private Cloud
    • Public Cloud
    • Hybrid Cloud
    • Community Cloud
    • Infrastructure as a Service (IaaS)
    • Software as a Service (SaaS)
    • Platform as a Service (PaaS)
  • Cloud Characteristics
    • Shared Resources
    • Metered Utilization
    • Rapid Elasticity
    • High Availability
    • File Synchronization
  • Desktop Virtualization
    • Virtual Desktop Infrastructure (VDI) on Premises
    • VDI in the Cloud

Cloud Models

What is the cloud?  The cloud is a place where we can store and process our data without worrying about the underlying hardware.  There are several types of cloud models

IaaSInfrastructure as a Service  

We rent physical infrastructure on an hourly/daily/monthly basis

There are no upfront costs or hardware maintenance costs

We do not pay for internet, power, heating, cooling, etc.

We have access to each system hardware component and are responsible for configuring them.   Examples include Amazon Web Services and Microsoft Azure  
SaaSSoftware as a Service  

We are paying for the right to use a software application

The software is licensed on a per hour or per month basis.

The software is centrally hosted. 

We do not manage the software code, hardware, or licenses.   Example includes Salesforce  
PaaSPlatform as a Service  

Hybrid service between IaaS and SaaS   A “platform” is licensed per hour or per month.

We do not manage hardware directly.  The hardware is an abstract concept that we can use to run any application we want.   The advantage of PaaS is the ability to run applications without having to build the underlying infrastructure.  
Public CloudA public cloud one that is available to the general public.

The resources inside a public cloud are shared amongst all customers, which improves efficiency and reduces cost.

Multiple customers may be present on the same physical server without realizing it (cloud software is supposed to prevent data leaks between customers)

The public cloud has risks and some users choose to have their applications run on dedicated hardware  
Private CloudA private cloud is built by one organization for its internal use.

A large organization can use a private cloud to share resources amongst different departments.

The private cloud improves efficiency because multiple departments can share the same hardware  
Hybrid CloudThe hybrid cloud is a mix of a private cloud and a public cloud.  

A company may decide that some applications are too sensitive to host on a public cloud, or that some applications will not run properly when they are off site but would like to take advantage of the public cloud.  

Applications that can run on the public cloud are placed there, and remaining applications are placed on a private cloud.  

The private cloud and public cloud are connected via a WAN or VPN.  They act like they are part of the same physical network.

Community CloudA community cloud is like a private cloud except that infrastructure is shared by several organizations.

For example, a city can set up a private cloud.  The fire department uses part of it, the water works uses part of it, and the police department uses part of it.

Cloud Benefits

There are five essential characteristics of a cloud computing service

  • On-demand self service
  • Broad network access
  • Resource pooling
  • Rapid elasticity
  • Measured service
Shared ResourcesThe cloud must allow multiple users to share computer resources, including

File storage
Network connectivity  
Rapid ElasticityThe cloud must have the ability to instantly add or remove capacity.  A resource can scale on demand.  

Scaling can happen automatically (via a script that detects an overload) or manually at the request of a user.  
On-DemandA user can obtain cloud services “on demand” from a control panel  
Resource PoolingResources are shared across multiple customers.  When a resource is released by one customer, it can be allocated to another  
Measured ServicesThe cloud provider can measure the quantity of services used by each customer.  A user is billed for resources that he or she consumes.  
MeteredA cloud provider can meter or limit the amount of resources a user can use.   This is important because a user could request too many resources at once, which could impact other customers.  
High AvailabilityThe cloud must have a high level of availability.    This is achieved by having multiple levels of hardware redundancy, and multiple data centers in different geographic locations.  
File SynchronizationThe cloud must synchronize user files across multiple locations and multiple redundant systems.   Files that are placed on one system should be instantly available on other systems.

Off-Site E-mail Applications

There are three main cloud e-mail services

G SuiteProvided by Google  

Billed on a per-user per-month license  

Includes the following services

-E-mail (Gmail)
-File Sharing (Google Drive)
-Calendar (Google Calendar)
-Hangouts (Chat and Collaboration)

E-mail can be accessed via a web app or via an e-mail client, such as Outlook  
ExchangeProvided by Microsoft  

Billed on a per-user per-month license  

E-mail can be accessed via a web app or via an e-mail client, such as Outlook  
Office 365Provided by Microsoft  
Billed on a per-user per-month license  
Includes all the features of Exchange plus each user can install Office 365 on up to five devices  


-Office 365 includes Excel, Word, Outlook, PowerPoint, Access, and Skype
-Teams allows users to communicate via messaging, voice, and video
-Store files in the cloud with OneDrive
-SharePoint allows a company to create internal websites

Additional features

-Integration with active directory
-Data Leak Prevention
-Message encryption  

Cloud Storage

There are five main cloud storage services

Google DriveProvided by Google

Free for personal use

Pay for business use on a per-user per month basis (integrates with Google Workspaces)

Files are available through a web interface

Can share files and folders with internal and external users  
One DriveProvided by Microsoft

Free for personal use

Pay for business use on a per-user per month basis (integrated with Office 365)

Files are available through a web interface, and through a downloadable app

Allows you to sync files between your computer and the cloud

Can share files and folders with internal and external users  
SharePointProvided by Microsoft

Pay per-user per-month

Available with an Office 365 business license

Allows you to create internal corporate websites, accessible through a web interface

Can share files and folders with internal and external users  
Amazon WorkDocsProvided by Amazon Web Services

Pay per-user per-month

Files are available through a web interface, and through a downloadable app

Allows you to sync files between your computer and the cloud

Can share files and folders with internal and external users  
Dropbox / BoxCloud apps that provide file sharing

Free for personal use

Pay for business use

Can share files and folders with internal and external users

Virtual Application Streaming/Cloud-Based Applications/Virtual Desktops

A virtual desktop is a concept where we open a remote session with a server, and we run the applications on the server.  Nothing runs on our physical computer.  We can disconnect our session and reconnect it on the same computer or another computer, and our applications will be just like we left them.

Why do we want to do this?

  • We can use cheaper local hardware because we are not running any applications on it.

  • The data is stored on a remote server, which can be on a secure location.  The local hardware will not contain any sensitive data. 

  • A single server can support dozens or hundreds of users.

  • It is easier to upgrade applications on a single server than on many user desktops

There are a few ways to deliver virtual desktops

CitrixCitrix creates a system called “application virtualization”Itallows a user to run an application regardless of the type of computer system he is using   How?

The application runs on a Citrix serverThe user runs a “plug in” on his computer that connects to the serverThe server streams the application through the plugin to the user over the internetWe call this concept “containerization” because the user only receives the specific resources he needs to run the application


Application will operate on any type of computer
Application data is stored centrally on Citrix server and can be backed up easily


Requires internet to function
There are licensing costs associated with Citrix      
Amazon WorkSpacesWorkSpaces is a Cloud Desktop Service   User “desktops”, files, applications, and computing resources are stored in the Amazon cloud

A user can install the WorkSpaces client on their Windows, iOS, Apple, or Android device and connect to their desktop

The desktop is in the cloud, so a user can connect to it from multiple locations, and begin working where they left off

It is easy to back up the WorkSpaces, even while they are in use

Integrates with Active Directory and other authentication protocols

WorkSpaces allows a customer to scale a desktop to hundreds or thousands of users instantly

Customer is billed for each WorkSpace in use on an hourly basis; customer is only billed for WorkSpaces when they are actually in use

A user must have access to the internet to use WorkSpaces  
Remote Desktop ServicesRemote Desktop Services (RDP) is a feature of the Microsoft Server Operating System

A central server stores user desktops, applications, and settings

The server can be hosted in the cloud or on premises, but must stay operating to facilitate user access

If we put the RDP service in the cloud, then we must have a reliable, low latency internet connection

A user can connect to the server via a Remote Desktop Protocol from any Windows device

RDP requires a per-user license (CAL) to access the server