DevOps, SRE & Cloud Interview · Cloud Fundamentals · Lesson 1 of 2
AWS core: compute, storage, networking, IAM
You do not need every AWS service, but you must place the core building blocks and the model behind them. Every cloud has equivalents; the concepts transfer.
Compute
- EC2: virtual machines you manage. Lambda: serverless functions, event-driven, pay-per-invocation, no servers to run.
- ECS / EKS: run containers (EKS = managed Kubernetes). Fargate: serverless containers (no nodes to manage).
Storage & data
- S3: object storage — durable (11 nines), cheap, for blobs/backups/static assets. EBS: block volumes attached to EC2. EFS: shared network file system.
- RDS: managed relational DB; DynamoDB: managed key-value/NoSQL at scale.
Networking & identity
- VPC: your private network — subnets (public/private), route tables, security groups (stateful, instance-level) and NACLs (stateless, subnet-level).
- IAM: who can do what. Prefer roles (temporary credentials) over long-lived access keys; grant least privilege.
The shared responsibility modelAWS secures the cloud (of the cloud — hardware, hypervisor, managed services); you secure what you run in the cloud — IAM policies, data encryption, patching your instances, network config. Naming this split is a common cloud-interview checkpoint.
◆ Lock it in
- Compute: EC2 (VMs), Lambda (serverless), EKS/ECS/Fargate (containers).
- Storage: S3 (objects), EBS (block), RDS/DynamoDB (databases).
- VPC isolates the network; IAM roles + least privilege govern access; know the shared responsibility model.
Feynman drill — say it out loudExplain the shared responsibility model with one concrete example of an AWS responsibility and one of yours.
Step 1 rate your confidence · Step 2 pick your answer
Under the AWS shared responsibility model, which task is the customer's responsibility?
Step 1 — how sure are you?