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nexus/wiki/concepts/Cloud-Computing.md
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---
title: "Cloud Computing"
type: concept
tags: [cloud, infrastructure, iaas, paas, saas]
sources: [the-myths-and-misconceptions-about-cloud-computing-linkedin, what-i-know-about-cloud-service-delivery-1, cloud-maturity-model-a-detailed-guide-for-cloud-adoption]
last_updated: 2025-03-02
---
## Definition
Cloud computing is the delivery of computing services—including servers, storage, databases, networking, software, analytics, and intelligence—over the Internet ("the cloud") to offer faster innovation, flexible resources, and economies of scale.
## Service Models
- **IaaS (Infrastructure as a Service)**: Provides virtualized computing resources over the internet (e.g., AWS EC2, Azure VMs)
- **PaaS (Platform as a Service)**: Provides a platform for developing, running, and managing applications without dealing with infrastructure (e.g., AWS Elastic Beanstalk, Azure App Service)
- **SaaS (Software as a Service)**: Provides software applications over the internet on a subscription basis (e.g., Microsoft 365, Salesforce)
## Key Characteristics
- **On-demand self-service**: Provision resources as needed without human intervention
- **Broad network access**: Access services over the network via standard mechanisms
- **Resource pooling**: Multiple customers share infrastructure with logical separation
- **Rapid elasticity**: Scale resources up or down dynamically
- **Measured service**: Pay-as-you-go pricing model
## Common Misconceptions
According to [[the-myths-and-misconceptions-about-cloud-computing-linkedin]], the following misconceptions are prevalent:
1. **Cloud is not secure** → Reality: Major providers invest heavily in security (encryption, MFA, ISO 27001, HIPAA, GDPR compliance)
2. **Cloud is just "someone else's computer"** → Reality: Cloud is a sophisticated network of data centers with redundancy and high availability
3. **Cloud is too expensive** → Reality: Pay-as-you-go model with proper management can be cost-effective
4. **You lose control of your data** → Reality: Cloud provides robust data governance and control tools
5. **Cloud is only for large enterprises** → Reality: SMBs can leverage enterprise-grade technology without large upfront investments
6. **Migration is too complex** → Reality: Phased migration and hybrid cloud solutions mitigate risks
7. **Cloud performance is unreliable** → Reality: SLAs often guarantee 99.99%+ uptime
## Related Concepts
- [[Hybrid-Cloud]]: Combining on-premises infrastructure with public cloud
- [[Multi-Cloud]]: Using multiple cloud providers simultaneously
- [[Cloud-Migration]]: The process of moving workloads to the cloud
- [[Cloud-Security]]: Security practices in cloud environments
- [[Pay-as-you-go]]: Cost model based on actual usage
- [[High-Availability]]: Design principle for minimizing downtime
- [[Serverless-Computing]]: Event-driven computing without server management
## Aliases
- Cloud
- 云计算