Stylized cloud connected to three devices
CIT-1107
Cloud Computing Fundamentals
Virtualization, service models, capacity, and the cloud behind IoT and mobile
Dr. Mike Libassi
TODAY
Today's roadmap
01
Virtualization and the cloud
How one physical server becomes many, and why that makes cloud possible
02
Service models: SaaS, PaaS, IaaS
Who manages what, with real-world examples
03
Cloud capacity vs. on-prem servers
Buying for the peak vs. scaling with demand
04
Cloud with IoT and mobile
The back end behind smart devices and the apps on your phone
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PART 1 · FOUNDATION
Virtualization: one server, many machines
A hypervisor carves one physical server into many isolated virtual machines (VMs).
Hypervisor
Shares out CPU, memory, storage, and network. Examples: VMware ESXi, Hyper-V, KVM.
Isolation
Each VM runs its own OS and apps. A crash in one doesn't take down the others.
VMs are files
Copy, snapshot, or move them to new hardware in minutes.
Diagram: three virtual machines, each with its own app and operating system, run on a hypervisor on top of one physical server
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PART 1 · FOUNDATION
From virtualization to cloud
Cloud = virtualized resources + automation + self-service, delivered over a network.
NIST's five essential characteristics of cloud computing
01
On-demand self-service
Spin up a server from a web portal. No ticket, no waiting.
02
Broad network access
Reach it from laptops, phones, and other devices over the network.
03
Resource pooling
Many customers share the provider's virtualized hardware.
04
Rapid elasticity
Add or remove capacity in minutes, often automatically.
05
Measured service
Usage is metered, so you pay for what you use.
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PART 2 · SERVICE MODELS
SaaS · PaaS · IaaS
Three ways to rent the cloud. Each one hands a different share of the work to the provider.
PART 2 · SERVICE MODELS
Who manages what?
Layer
On-prem
IaaS
PaaS
SaaS
Applications
You
You
You
Provider
Data and access
You
You
You
You
Runtime and middleware
You
You
Provider
Provider
Operating system
You
You
Provider
Provider
Virtualization
You
Provider
Provider
Provider
Servers and storage
You
Provider
Provider
Provider
Networking
You
Provider
Provider
Provider
Rule of thumb: you always own your data and who can access it, even in SaaS.
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SERVICE MODEL 1 OF 3
Software as a Service (SaaS)
Finished applications delivered over the internet, usually by a third party. Open a browser or app, sign in, and use it.
YOU MANAGE
Your data, your users, and settings
PROVIDER MANAGES
The app, servers, updates, and patches
Pizza analogy: dining out. You just eat.
EXAMPLES
Microsoft 365
Outlook, Word, and Teams in the browser
Google Workspace
Gmail, Docs, and Drive
Salesforce
Customer relationship management (CRM)
Zoom
Video meetings with nothing to host
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SERVICE MODEL 2 OF 3
Platform as a Service (PaaS)
A ready-made platform (runtime, database, developer tools) for building and deploying your own apps. No servers or OS to manage.
YOU MANAGE
Your code, your data, and app settings
PROVIDER MANAGES
Runtime, OS, servers, scaling, and patches
Pizza analogy: delivery. You set the table.
EXAMPLES
Heroku
Push your code and it runs
Google App Engine
Hosts web apps and APIs at scale
AWS Elastic Beanstalk
Deploys and scales web apps on AWS
Azure App Service
Hosts web apps, APIs, and mobile back ends
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SERVICE MODEL 3 OF 3
Infrastructure as a Service (IaaS)
Pay-as-you-go virtual servers, storage, and networking. The provider runs the data center; you build everything on top.
YOU MANAGE
OS, patches, firewall rules, apps, and data
PROVIDER MANAGES
Physical hardware, virtualization, facility
Pizza analogy: take-and-bake. You supply the oven.
EXAMPLES
Amazon EC2
Virtual servers billed by the second or hour
Azure Virtual Machines
Windows and Linux VMs on demand
Google Compute Engine
VMs on Google's global network
Amazon S3
Storage, paid per gigabyte stored
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QUICK CHECK
SaaS, PaaS, or IaaS?
1
A student writes an essay in Google Docs.
2
A startup deploys its Python web app to Heroku without touching a server.
3
The IT team launches a Linux VM on Amazon EC2 and installs the Apache web server.
4
The sales team tracks every customer call in Salesforce.
5
A company rents virtual servers, storage, and networks in Azure to replace its server room.
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PART 3 · CAPACITY
Capacity: fixed vs. elastic
Illustrative chart: demand rises and spikes over a year. A flat on-prem capacity line sits above demand most of the year, leaving idle capacity, but falls below the spike. A stepped cloud capacity line follows demand closely.
On-prem: buy for the peak
Hardware sized for the busiest day sits idle most of the year. Size it lower, and the spike causes slowdowns or outages.
Cloud: match the demand
Auto-scaling adds servers as traffic climbs and removes them when it drops. You pay for what you use.
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PART 3 · CAPACITY
On-prem vs. cloud at a glance
On-prem servers
Cloud
Upfront cost
Buy servers up front (CapEx)
Little to none; pay monthly (OpEx)
Adding capacity
Weeks: order, ship, rack, configure
Minutes, from a portal or script
Scaling
Fixed ceiling; manual upgrades
Elastic; can scale automatically
Upkeep
Your staff: power, cooling, repairs
Provider runs the data center
Control
Full control of hardware and data
Shared responsibility; less control
Best fit
Steady, predictable workloads
Variable or fast-growing workloads
In practice: many organizations run hybrid, with some systems on-prem and some in the cloud.
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PART 4 · IOT AND MOBILE
IoT: devices sense, the cloud thinks
Flow diagram: IoT devices send data to a gateway or edge device, which forwards it to a cloud platform for storage and analysis, which feeds apps and alerts. Commands and firmware updates flow back from the cloud to the devices.
Scale
Take in data from thousands or millions of devices.
Analyze
Store long histories and spot patterns.
Control
Send commands and updates back out.
Secure
Every device is an entry point to protect.
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PART 4 · IOT AND MOBILE
Mobile: the phone's cloud back end
Your phone holds the screen. The cloud holds the data, the identity, and the heavy computing.
Sync and backup
Photos and files copy to iCloud or Google Photos and show up on every device.
Sign-in and identity
One account works across your phone, laptop, and the web.
Push notifications
Cloud services wake your app with messages and alerts.
Heavy lifting
Voice assistants, map routing, and translation run on cloud servers.
Developers often build these with mobile back-end platforms such as Firebase and AWS Amplify (a PaaS flavor).
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RECAP
Key takeaways
01
Virtualization is the foundation
Hypervisors turn one server into many VMs; the cloud pools them and rents them out.
02
Service models split the work
IaaS: you run the OS and up. PaaS: you bring the code. SaaS: you just use it.
03
Cloud capacity follows demand
Elastic and pay-as-you-go, instead of buying hardware for the peak.
04
IoT and mobile run on the cloud
It supplies the storage, sync, analytics, and control that small devices can't.
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