Fundamentals
Cloud computing lets organizations rent compute, storage, and managed services from providers such as AWS, Azure, and Google Cloud instead of owning all infrastructure directly. This article is the overview node for cloud computing; specific AWS topics live in their own articles (see Related AWS Topics).
Hybrid Cloud
Hybrid cloud combines private cloud or on-premises infrastructure with one or more public clouds.
Use case: keep sensitive data in a private environment while using public cloud for scalable customer-facing applications.
Benefits:
- security for sensitive data
- scalability for variable workloads
- flexibility to move workloads
- regulatory compliance
Multi-Cloud
Multi-cloud uses services from more than one public cloud provider.
Reasons:
- avoid vendor lock-in
- optimize costs
- use best services from different providers
Example: Google Cloud for analytics, AWS for hosting, and Azure for AI services.
Hybrid Cloud Vs Multi-Cloud
| Aspect | Hybrid cloud | Multi-cloud |
|---|---|---|
| Infrastructure | private + public | multiple public clouds |
| Integration | unified environment | independent services |
| Goal | workload movement | best-of-breed and lock-in reduction |
Auto-Scaling
Auto-scaling adds or removes compute resources based on metrics such as CPU, memory, network traffic, or custom metrics.
It optimizes cost and availability by matching capacity to demand.
Load Balancing
Load balancing distributes incoming requests across backend targets.
Auto-scaling changes the number of resources. Load balancing distributes traffic across those resources.
Related AWS Topics
- AWS Fundamentals: the Well-Architected Framework, Cloud Adoption Framework, the 7 Rs migration strategies, and migration services.
- AWS EC2: creating, connecting to, and stopping EC2 instances.
- Cloud Security: encryption, IAM, MFA, VPCs, security groups, and monitoring.
- Lambda Function: event-driven serverless functions.
References
- AWS Documentation
- AWS Well-Architected Framework
- AWS Cloud Adoption Framework
- AWS Management Console
- AWS Free Tier
Security
Cloud security protects data, systems, identities, and networks in public or hybrid cloud environments.
Data Encryption
Encryption at rest protects stored data such as EBS volumes, S3 buckets, and databases.
Encryption in transit protects data moving across networks. Use TLS, HTTPS endpoints, and encrypted database connections.
IAM
Identity and Access Management controls who can access which resources.
Principle of least privilege: users and services should receive only the permissions they need.
MFA And Temporary Credentials
Use MFA for users, especially privileged accounts. Prefer temporary role-based credentials over permanent access keys.
Network Security
Use a VPC to isolate resources. Put public entry points in public subnets and sensitive resources such as databases in private subnets.
Security groups act as virtual firewalls. Open only the ports required.
Monitoring And Logging
Use CloudTrail for audit logs and CloudWatch for monitoring. Alerts should flag suspicious activity and operational failures.
AWS EC2 security depends heavily on security group rules, key management, and instance lifecycle discipline.