What is Cloud Computing?

Key Takeaways​

Cloud computing is the on-demand delivery of compute, storage, database, and networking resources over the internet with pay-as-you-go pricing.

[ On-Demand Request ] ---> ( Cloud Service Provider ) ---> [ Instant Provisioning ]
                                                                   |
                                                        [ Pay ONLY for What You Use ]

Instead of buying, owning, and maintaining physical data centers, you rent access to virtualized technology services from a cloud provider like Amazon Web Services (AWS). This eliminates guessing capacity and turns heavy upfront capital expenses into variable operational costs.

Main Discussion​

The Three Cloud Deployment Models​

Organizations adopt cloud infrastructure across three distinct deployment models based on compliance, control, and architectural requirements:

+-----------------------------------------------------------------------+
| PUBLIC CLOUD (AWS, Azure, GCP)                                        |
| Shared, highly scalable global infrastructure accessed over internet  |
+-----------------------------------------------------------------------+
                                   |
                                   v  (Connected via Direct Connect / VPN)
+-----------------------------------------------------------------------+
| HYBRID CLOUD                                                          |
| Integrates on-premises/private infrastructure with public cloud       |
+-----------------------------------------------------------------------+
                                   ^
                                   |
+-----------------------------------------------------------------------+
| PRIVATE CLOUD (On-Premises / Rackspace)                               |
| Dedicated single-tenant hardware; maximum control and isolation       |
+-----------------------------------------------------------------------+

• Public Cloud: Fully owned and operated by third-party cloud service providers (CSPs) like AWS. Resources are delivered over the public internet.
• Private Cloud: Cloud infrastructure deployed exclusively for one organization. Offers strict data isolation but lacks massive scalability.
• Hybrid Cloud: Connects existing on-premises data centers to the public cloud, allowing organizations to retain sensitive legacy data locally while scaling cloud-native apps on AWS.

The 5 Essential Characteristics of Cloud Computing​

The National Institute of Standards and Technology (NIST) defines cloud computing through five foundational pillars:

$\text{Cloud Utility} = \text{On-Demand Self-Service} + \text{Broad Access} + \text{Multi-Tenancy} + \text{Rapid Elasticity} + \text{Measured Service}$

                          +-------------------------------+
                          |  5 CLOUD CHARACTERISTICS      |
                          +-------------------------------+
                                          |
        +------------------+--------------+--------------+------------------+
        |                  |                             |                  |
        v                  v                             v                  v
[ On-Demand Self-  [ Broad Network Access ]      [ Multi-Tenancy &   [ Elasticity & Measured
    Service ]      (Internet/Multi-Device)       Resource Pooling ]      Usage Scaling ]
(Instant Provision)                              (Shared Hardware)     (Auto-scale & Pay-per-sec)

1. On-Demand Self-Service: Provision compute resources instantly without human intervention from AWS.
2. Broad Network Access: Resources are accessible over standard network protocols across diverse client platforms (web browsers, mobile, APIs).
3. Multi-Tenancy & Resource Pooling: Multiple customers (tenants) share the same physical underlying hardware while remaining securely isolated.
4. Rapid Elasticity & Scalability: Automatically scale resources out (add capacity during traffic spikes) and in (release capacity when idle).
5. Measured Service: Usage is metered down to the second/gigabyte, ensuring pay-as-you-go financial transparency.

The 6 Core Business Advantages of AWS Cloud​

+-------------------------------------------------------------------------+
|                       6 ADVANTAGES OF THE CLOUD                         |
+-------------------------------------------------------------------------+
| 1. Trade Capital Expense (CapEx) for Variable Operational Expense (OpEx)|
| 2. Benefit from Massive Economies of Scale (Lower Pay-Per-Use Rates)    |
| 3. Stop Guessing Capacity (Auto-Scale Up or Down On-Demand)             |
| 4. Increase Speed and Agility (Launch Infrastructure in Seconds)        |
| 5. Stop Spending Money Running and Maintaining Data Centers             |
| 6. Go Global in Minutes (Deploy Applications Across Worldwide Regions)  |
+-------------------------------------------------------------------------+

Exam Guide​

Exam Tips​

• CapEx vs. OpEx Tradeoff: Remember that cloud computing converts CapEx (upfront hardware investments, server racks, real estate) into OpEx (pay-as-you-go variable expenses based on actual consumption).
• Multi-Tenancy Isolation: Multi-tenancy means multiple AWS accounts share physical servers underneath, but hypervisor-level security guarantees absolute logical data separation.
• Hybrid Deployment Patterns: Look for exam questions involving security/regulatory constraints where companies keep core databases on-premises while expanding web layers into AWS—this is always a Hybrid Cloud model.

Practice Test​

Question 1​

A startup wants to launch an AI model inference API without purchasing physical server hardware or paying upfront data center leases. Which advantage of cloud computing best describes this financial shift?

• A. High capital expenditure with low operational agility
• B. Trading capital expenses (CapEx) for operational expenses (OpEx)
• C. Manual capacity guessing for fixed infrastructure scaling
• D. High total cost of ownership (TCO) through dedicated single-tenancy

Question 2​

A enterprise financial firm maintains sensitive user records in an on-premises database due to legal compliance, but uses Amazon Bedrock in AWS to run generative AI summaries. Which cloud deployment model is this enterprise utilizing?

• A. Private Cloud
• B. Public Cloud
• C. Hybrid Cloud
• D. Multi-Region Serverless Cloud