Cloud Technology and Services: Compute, Storage, Networking, and Databases
Compute choices
Know when to pick each option. EC2 gives full control of virtual servers. Lambda runs code without servers, event-driven, billed per request and duration. Containers on ECS or EKS suit portable packaged workloads. Elastic Beanstalk handles application deployment plumbing. Fargate removes server management for containers. Trap: choosing EC2 when the requirement is "no server management" or "pay only when code runs" - that points to Lambda or Fargate.
Storage classes
S3 is object storage with classes tuned to access patterns: Standard, Standard-IA, One Zone-IA, Glacier tiers, and Intelligent-Tiering. EBS is block storage attached to one EC2 instance in one AZ. EFS is shared elastic file storage for Linux workloads across AZs. Instance store is ephemeral. Trap: using EBS for shared multi-instance access, or assuming S3 is a file system you can mount as a disk.
Networking
A VPC is your isolated network. Subnets are public or private depending on route tables. An internet gateway connects a VPC to the internet; a NAT gateway lets private subnets reach outbound. Security groups are stateful; network ACLs are stateless. Route 53 is DNS, CloudFront is the CDN, and Direct Connect provides dedicated private connectivity. Trap: placing a NAT gateway in a private subnet without a route to an internet gateway.
Databases and decoupling
RDS is managed relational; Aurora is a high-performance compatible engine; DynamoDB is managed NoSQL with predictable low latency; Redshift is analytics. SQS decouples producers and consumers; SNS is pub/sub fan-out. Rule of thumb: read the requirement's operative phrase - "shared file access across instances" means EFS, "durable object storage for any amount of data" means S3, "queue between tiers" means SQS.