Cloud Computing — Definition & Overview
Cloud computing is the delivery of computing resources (servers, storage, databases, networking, software, analytics, and intelligence) over the internet (“the cloud”) to offer faster innovation, flexible resources, and economies of scale. Instead of owning physical data centers or servers, organizations rent access to services from a cloud provider on a pay-as-you-go basis.
Core Characteristics
Cloud computing usually exhibits the following characteristics: on-demand self-service, broad network access, resource pooling (multi-tenancy), rapid elasticity (scaling), and measured service (pay-per-use).
Main Service Models (IaaS, PaaS, SaaS)
IaaS (Infrastructure as a Service): Provides virtualized computing resources over the internet. Example: EC2, Google Compute Engine, Azure Virtual Machines.
PaaS (Platform as a Service): Offers hardware and software tools (platform) for developers to build, test, and deploy applications. Example: Heroku, Google App Engine, Azure App Services.
SaaS (Software as a Service): Delivers software applications over the internet on a subscription basis. Example: Salesforce, Google Workspace, Microsoft 365.
Deployment Models
Public Cloud: Services run on infrastructure owned by third-party cloud providers and delivered over the internet to multiple tenants.
Private Cloud: Infrastructure dedicated to a single organization—either on-premises or hosted by a provider—provides greater control and customization.
Hybrid Cloud: Combination of public and private clouds that allows data and applications to move between them for greater flexibility and optimization.
Benefits of Cloud Computing
Cost savings (pay-as-you-go), scalability, faster time-to-market, improved reliability, global reach, and simplified management are the primary benefits organizations gain from cloud adoption.
Common Use Cases
Web hosting and application hosting, data backup and disaster recovery, big data analytics, machine learning workloads, development and testing environments, and global content delivery.
Security & Best Practices
Cloud providers offer strong security controls, but customers share responsibility. Key best practices: encrypt data in transit and at rest, implement identity and access management (least privilege), enable multi-factor authentication (MFA), maintain strong logging and monitoring, and apply network segmentation and secure configuration.
Quick Example (CLI)
Launching a virtual machine with AWS CLI (example):
aws ec2 run-instances --image-id ami-0abcdef1234567890 --count 1 --instance-type t3.micro --key-name MyKeyPair --security-group-ids sg-0123456789abcdef0
How to Answer This in an Interview
Keep your answer concise: define cloud computing, mention key characteristics, briefly explain IaaS/PaaS/SaaS and deployment models, highlight business benefits, and mention security responsibilities. If relevant, tie the answer to your experience or a short example where you used cloud services.
Keywords: Cloud Computing, IaaS, PaaS, SaaS, public cloud, private cloud, hybrid cloud, scalability, cost savings, cloud security.