Cloud Computing Lab (IT-704) - Unit 1 Short Notes

A. Introduction to Cloud Computing & Virtualization

Defining Cloud Computing

A model for enabling ubiquitous, convenient, on-demand network access to a shared pool of configurable computing resources (e.g., networks, servers, storage, applications, services).
Five Essential Characteristics (NIST Definition):

1. On-demand self-service: Provision resources automatically without human interaction.

2. Broad network access: Available over the network via standard mechanisms (e.g., HTTP/HTTPS).

3. Resource pooling: Multi-tenant model with physical and virtual resources dynamically assigned.

4. Rapid elasticity: Resources scale rapidly outward and inward with demand.

5. Measured service: Resource usage monitored, controlled, and billed transparently.

Evolution & Deployment Models

[!TIP] Exam Focus: Be prepared to justify the choice of a deployment model for a given scenario (e.g., "A bank with strict regulatory requirements would likely choose Private or Hybrid cloud").

Core Technology Enabler: Virtualization
What is Virtualization?

The creation of a virtual (rather than actual) version of something, including virtual hardware platforms, storage devices, and network resources. It enables multiple isolated guest operating systems to run on a single physical host machine.

Key Components:

• Hypervisor (Virtual Machine Monitor - VMM): Software layer that creates and runs VMs.

  • Type 1 (Bare-metal): Runs directly on host hardware. (e.g., VMware ESXi, Microsoft Hyper-V, Xen).

  • Type 2 (Hosted): Runs on a conventional OS as an application. (e.g., VirtualBox, VMware Workstation).

• Virtual Machine (VM): An emulation of a physical computer, consisting of a virtual CPU (vCPU), virtual memory (vRAM), virtual storage (vDisk), and virtual network (vNIC).

Types of Virtualization:

1. Full Virtualization: Guest OS runs unmodified; hypervisor traps and emulates privileged instructions. (e.g., VMware, VirtualBox).

2. Para-virtualization: Guest OS is modified to make system calls directly to the hypervisor (more efficient). (e.g., Xen in PV mode).

3. Hardware-assisted Virtualization: CPU provides extensions (Intel VT-x, AMD-V) to assist hypervisor, enabling near-native performance for unmodified OS.

[!TIP] Common Pitfall: Confusing Type 1 (production, datacenter) with Type 2 (desktop, testing) hypervisors. Remember: Type 1 sits on bare metal.

B. Cloud Service Models (The SPI Framework)

[!TIP] Exam Formula: The "Responsibility Pyramid" is key. Remember the mnemonic: "IaaS: I manage Everything above the Infrastructure. SaaS: I manage Nothing."

Control decreases from IaaS → PaaS → SaaS. Provider management responsibility increases from IaaS → PaaS → SaaS.

C. Introduction to Major Cloud Providers & Their Core Services

1. Amazon Web Services (AWS)

• Global Infrastructure: Regions (geographic areas) → Availability Zones (AZs) (isolated locations within a region) → Edge Locations (for CloudFront CDN).

• Core IaaS Services:

  • EC2 (Elastic Compute Cloud): Scalable VMs. Key concepts: Instances (VM sizes), AMIs (templates), Key Pairs (SSH auth).

  • S3 (Simple Storage Service): Object storage. Buckets (containers) hold Objects (files). Used for static websites, backups.

  • VPC (Virtual Private Cloud): Isolated virtual network. Define Subnets (public/private), route tables, internet gateway.

  • IAM (Identity and Access Management): Manage users, roles, and policies (JSON documents defining permissions).

2. Microsoft Azure

• Global Infrastructure: Regions → Availability Zones (in select regions).

• Core IaaS Services:

  • Virtual Machines: Similar to EC2. Use Images (marketplace/custom).

  • Blob Storage: Object storage (like S3). Containers hold Blobs.

  • Virtual Network (VNet): Equivalent to VPC. Subnets, Network Security Groups (NSGs) (firewall rules).

  • Azure Active Directory (AAD): Identity and access management service (cloud-based).

3. Google Cloud Platform (GCP)

• Global Infrastructure: Regions → Zones (equivalent to AZs).

• Core IaaS Services:

  • Compute Engine: VM service. Images, Machine Types.

  • Cloud Storage: Object storage. Buckets hold Objects.

  • VPC: Global, scalable network. Subnets per region.

  • Cloud IAM: Unified identity management. Members, roles, policies.

Provider Service Mapping (High-Level):

[!TIP] Exam Trap: Don't get bogged down in every service name. Focus on the conceptual equivalents (e.g., "Where do I define firewall rules?" → SG/NSG/Firewall). The naming differs, the concepts are similar.

D. Foundational Lab Setup & First Hands-On

1. Account & Access Setup

• Sign up for Free Tier (AWS), Azure Pass/Free Account (Azure), or Free Trial (GCP). Always set up Billing Alerts immediately to avoid surprise charges.

• Understand the free tier limits (e.g., 750 hours of t2.micro/t3.micro per month for 12 months on AWS).

2. Management Console & CLI

• Web Console: AWS Management Console, Azure Portal, GCP Console. Point-and-click GUI.

• Command Line Interface (CLI): Essential for automation and scripting.

  • aws <service> <command> (e.g., aws ec2 describe-instances)

  • az <group> <command> (e.g., az vm list)

  • gcloud <service> <command> (e.g., gcloud compute instances list)

• Basic CLI Flow: Authenticate (aws configure/az login/gcloud auth login), then use commands to list, create, delete resources.

3. First Practical Exercise: Launching a Virtual Machine Generic Step-by-Step (Provider-Agnostic):

1. Choose Region: Select a region with free tier availability.

2. Select Image: Choose an OS (e.g., Amazon Linux 2, Ubuntu Server, Windows Server).

3. Choose Instance Type/Size: Select a free-tier eligible size (e.g., t2.micro, B1s).

4. Configure Networking:

   • Create/select a Virtual Network/Subnet.

   • Enable Public IP assignment (crucial for external access).

   • Configure Security Group/Firewall/NSG: Add an inbound rule to allow SSH (port 22) for Linux or RDP (port 3389) for Windows from your IP (0.0.0.0/0 is insecure; use your specific IP).

5. Configure Authentication:

   • Linux: Create/select an existing SSH Key Pair. Download the .pem private key.

   • Windows: Let provider generate a random password, retrieve it using your key pair.

6. Launch & Connect:

   • Linux: ssh -i /path/to/key.pem ec2-user@<public-ip>

   • Windows: Use RDP client with public IP and retrieved password.

7. Verification & Cleanup:

   • Verify OS is running (ping, uptime).

   • (Optional) Install a web server: sudo yum install httpd (Amazon Linux) or sudo apt install apache2 (Ubuntu), start service, place index.html in /var/www/html/.

   • CRITICAL: Terminate/Delete the VM after the lab to stop incurring compute charges. Delete associated storage (EBS/disk) if not set to auto-delete.

[!TIP] Critical Lab Habit: ALWAYS TERMINATE RESOURCES. The #1 cause of unexpected cloud bills is forgotten VMs. Use provider Cost Explorer and Billing Alerts.

E. Cloud Economics & Basic Cost Estimation

Key Cost Drivers:

1. Compute: Charged per second (AWS, GCP) or minute (Azure) of VM runtime. Depends on instance type, OS, region.

2. Storage:

   • Block Storage (EBS/Disks): Per GB-month of provisioned storage + I/O operations.

   • Object Storage (S3/Blob): Per GB-month of data stored + requests (GET/PUT) + data retrieval.

3. Data Transfer: Egress (data leaving cloud provider's network) is almost always charged. Ingress (incoming) is typically free.

Pricing Models:

• On-Demand: Pay-as-you-go, no commitment. Highest hourly rate, maximum flexibility.

• Reserved Instances / Savings Plans (AWS) / Reserved VM Instances (Azure): Commit to 1 or 3 years for significant discount (up to 70%). Requires upfront/scheduled payment.

• Spot Instances / Preemptible VMs (GCP): Use unused capacity at deep discount (up to 90%). Can be terminated with short notice (2 min). Ideal for fault-tolerant, batch jobs.

Using Pricing Calculators:

1. Go to provider calculator (AWS Pricing Calculator, Azure Pricing Calculator, GCP Cloud Pricing Calculator).

2. Build a simple architecture: Add 1 x t2.micro (Linux) running 24/7 for a month + 1 x S3 Standard bucket with 10 GB stored.

3. Review breakdown: Note compute, storage, and any data transfer costs.

4. Estimate: The total monthly cost will be very low (often < $10) for this minimal setup within free tier.

Generic Cost Formula (Conceptual):

$$ \text{Total Monthly Cost} = \left( \text{Compute Hours} \times \text{Hourly Rate} \right) + \left( \text{Storage GB} \times \text{Rate per GB-month} \right) + \left( \text{Egress GB} \times \text{Rate per GB} \right) $$

\boxed{\text{Actual cost depends on region, service, and pricing model selected.}}

[!TIP] Exam Application: You may be asked to estimate the cost of a given diagram. Always state your assumptions (region, instance type, storage class, uptime hours). Free tier limits are your best friend for low-cost estimates.

F. Mini-Project / Capstone for Unit 1

Objective: Deploy a basic, functional web application using core IaaS components.

Scenario & Step-by-Step Implementation:

1. Launch a Linux VM: Follow the steps in Section D.3. Use a free-tier eligible instance (e.g., t2.micro). Ensure a public IP is assigned.

2. Configure Security: In the VM's security group/NSG, add an inbound rule to allow HTTP (port 80) from 0.0.0.0/0 (for testing; restrict in production).

3. Connect & Setup Web Server:

   
   # SSH into VM
   
   ssh -i mykey.pem ec2-user@<public-ip>
   
   # Update packages & install Apache (Amazon Linux/Ubuntu)
   
   sudo yum update -y        # Amazon Linux
   
   sudo yum install httpd -y
   
   sudo systemctl start httpd
   
   sudo systemctl enable httpd
   
   # OR for Ubuntu:
   
   # sudo apt update && sudo apt install apache2 -y
   
   # sudo systemctl start apache2
   
   # sudo systemctl enable apache2
   
   # Create a simple webpage
   
   echo "<h1>Hello from My Cloud VM!</h1>" | sudo tee /var/www/html/index.html
   
   

4. Verify Public Access: Open a browser and navigate to http://<public-ip>. You should see your "Hello from My Cloud VM!" message.

5. Document & Cleanup:

   • Screenshot 1: VM running in the cloud console.

   • Screenshot 2: Web browser displaying your hosted page.

   • Screenshot 3: Security group rule showing port 80 open.

   • Cost Estimate: Use the pricing calculator to estimate the monthly cost of this specific setup (1 x t2.micro 24/7 + 1 GB S3 bucket if used for storage). Note: If within free tier, cost may be $0.00.

   • Terminate the VM to stop all charges.

[!TIP] Project Defense: Be ready to explain each step's purpose:

• Why port 80? → Standard HTTP port for web traffic.

• Why public IP? → To make the web server accessible from the internet.

• Why systemctl enable? → Ensures web server starts on reboot.

• Why terminate? → Cost control is a fundamental cloud responsibility.