Definition and Core Idea
Cloud computing delivers on-demand computing resources—servers, storage, databases, networking, software, analytics, intelligence—over the internet. Instead of owning and maintaining physical infrastructure, organizations consume resources as services from cloud providers and pay only for what they use.
Key Characteristics
Cloud services typically exhibit:
- On-demand self-service: Provision resources automatically without human intervention.
- Broad network access: Accessible from any device with an internet connection.
- Resource pooling: Multiple customers share a provider’s resources (multi-tenancy).
- Rapid elasticity: Resources scale up or down quickly to meet demand.
- Measured service: Usage is monitored and billed based on consumption.
Service Models
Cloud computing is commonly offered in three service models:
- IaaS (Infrastructure as a Service): Virtualized compute, storage, and networking. Example: spinning up a VM in AWS EC2 or Azure Virtual Machines.
- PaaS (Platform as a Service): Managed platform for developing, running, and managing applications without dealing with underlying infrastructure. Example: Google App Engine, Heroku.
- SaaS (Software as a Service): Ready-to-use applications delivered over the internet. Example: Salesforce, Google Workspace, Microsoft 365.
Deployment Models
Common deployment models include:
- Public Cloud: Services provided over the public internet by third-party providers (AWS, Azure, GCP).
- Private Cloud: Cloud infrastructure operated solely for a single organization, on-premises or hosted.
- Hybrid Cloud: Combination of public and private clouds allowing data and application portability.
- Community Cloud: Shared among organizations with common concerns (e.g., regulatory requirements).
Benefits
Cloud adoption brings several advantages:
- Cost efficiency: Reduce capital expenditure (CapEx) and convert to operational expenditure (OpEx).
- Scalability: Match capacity to demand with autoscaling and managed services.
- Speed of innovation: Quickly provision resources and iterate faster.
- Global reach: Deploy applications closer to users with regional data centers.
- Managed services: Offload routine maintenance (patching, backups, monitoring) to providers.
Common Use Cases
Cloud is used for a wide range of workloads:
- Web and mobile application hosting
- Data analytics and big data processing
- Disaster recovery and backup
- Dev/Test environments and CI/CD pipelines
- Machine learning and AI platforms
Security and Compliance Considerations
Security remains a shared responsibility. Cloud providers secure the infrastructure, while customers must secure their data, applications, and access controls. Key practices include:
- Encrypt data at rest and in transit.
- Use Identity and Access Management (IAM) and least-privilege access.
- Enable logging, monitoring, and alerting.
- Apply network segmentation and private connectivity (VPN, Direct Connect).
- Understand compliance offerings (ISO, SOC, GDPR, HIPAA) provided by the vendor.
Quick Example (CLI)
Creating a virtual machine is a typical IaaS workflow. Example with AWS CLI:
aws ec2 run-instances --image-id ami-0123456789abcdef0 --count 1 --instance-type t3.micro --key-name MyKeyPair
Summary
Cloud computing transforms how organizations consume IT—shifting from owning infrastructure to leveraging scalable, flexible, and cost-effective services. Understanding service models (IaaS, PaaS, SaaS), deployment models, and the shared responsibility model is essential for designing secure and efficient cloud solutions.