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Lessons (40)

• Docker & Containers

  … Images, containers, Dockerfiles, layers, volumes, networks and Docker Compose, step by step. The big idea Before shipping containers …

• Pods: Where Your App Actually Runs

  Learn what a pod is, why it is not the same as a container, the common pod statuses …

• C4 Architecture Diagrams: Context, Container, Component and Code

  … C4 component diagram A component diagram zooms into one container , not the entire system. Choose a container where …

• Run Containers on AWS with ECR and ECS

  Build a container, store it in ECR, and run it on ECS Fargate without managing servers. The simple …

• Troubleshooting Playbook

  … The container exceeded its memory limit. bash kubectl top pod <pod --containers Raise the limit if the app …

• Containers at Scale: ECS Deep Dive and EKS

  … A memory limit breach can terminate a container, while a CPU limit can throttle it. Size requests from …

• Kubernetes: Start Here

  … the short version Kubernetes (K8s) runs containers for you. It runs them on one or many servers, restarts …

• NestJS Core Concepts

  … Nobody hires their own staff; the manager (the DI container) assigns them. ![A NestJS request passes middleware, guards …

• Internals, Upgrades, Resilience and Interview Questions

  … Pull image and start containers via CRI K- API: Report status Key point: components never talk to each …

• StatefulSets, DaemonSets, Jobs and CronJobs

  … Exists also run on tainted nodes containers: - name: agent image: fluent/fluent-bit:3.1 New node joins …

• Health Checks and Scaling

  … They are easy to confuse, so keep this table nearby. ![Liveness restarts a stuck container; readiness removes a …

• Serverless Architecture

  … invest in structured logs, tracing (X-Ray / OpenTelemetry) Cost at sustained high load Containers or VMs can be …

• Kubernetes Cluster Architecture, Simply

  … pull image and start container Node- API: report pod status The key point: components react to the shared …

• Multi-Account Strategy, Governance and Security Operations

  … 2. Contain : revoke sessions (attach an explicit deny with a TokenIssueTime condition), isolate the instance with a quarantine …

• Configuration, Secrets and Storage

  … Do not build separate images containing “development database” or “production database.” Put environment-specific settings outside the image …

• Cost Optimization and the Well-Architected Framework

  … check Performance Insights before upsizing. Quick wins by service EC2 and containers - Right-size using Compute Optimizer; move …

• Deployments: Keep Your App Running

  … registry.example.com/shop-api:1.8.0 ports: - containerPort: 3000 readinessProbe: httpGet: path: /health/ready port: 3000 …

• Practical Project: Deploy a Real CRM App on EKS

  Take a containerized CRM (DemoCRM) from source code to a secure AWS deployment: ECR images, an EKS cluster …

• Resources, QoS and Scheduling Control

  … runtime. - Going over a CPU limit throttles the container. Going over a memory limit kills it ( OOMKilled ). - A …

• Normalization & Denormalization

  … atomic values, no repeating groups Rule: each cell contains one value; every row has a key; do not …

• Extending Kubernetes: CRDs, Operators and Admission

  … resourceRules: - apiGroups: ["apps"] apiVersions: ["v1"] operations: ["CREATE", "UPDATE"] resources: ["deployments"] validations: - expression: object.spec.template.spec.containers.all …

• GitOps, Progressive Delivery and Observability

  … Example PromQL for restart storms: text increase(kube pod container status restarts total[15m]) 3 Smarter autoscaling Tool …

• D — Dependency Inversion Principle

  … pass dependencies in)"] DI -- C["DI Container<br/ (tool: wires it automatically)"] Key takeaways - Business logic should depend …

• Node.js and Express

  … 20 })); Graceful shutdown When Kubernetes or Docker stops your container it sends SIGTERM . Finish in-flight requests before …

• How Browsers Render a Page

  … forces layout on every iteration for (const box of boxes) { box.style.width = container.offsetWidth / 2 + "px"; } // ✅ Read …

• L6 Production Debugging Casebook

  … Compare dominator trees, retained size and growth by class; keep GC logs, allocation profiling/JFR, container memory limits …

• SQL vs NoSQL Databases

  … erDiagram CUSTOMER --o{ ORDER : places ORDER -- { ORDER ITEM : contains PRODUCT --o{ ORDER ITEM : "appears in" CUSTOMER { bigint id …

• What Is Software Architecture?

  … 2. Container Apps, databases, queues inside the system Developers, ops 3. Component Main modules inside one container Developers …

• Variables, Locals, Outputs, and Validation

  … variable "environment" { type = string default = "dev" validation { condition = contains(["dev", "stage", "prod"], var.environment) error message = "Environment must …

• Embeddings, Semantic Search, and RAG

  … Documents can contain prompt injection or stale claims. Enforce document permissions before retrieval, keep citations traceable, and avoid …

• Prompting and Structured Outputs

  … user-provided text as untrusted data; it may contain malicious instructions. - Enforce structure with schemas where possible, then …

• HCL, Resource Addresses, and Project Layout

  … A block contains a type, optional labels, and a body. An argument assigns an expression to a name …

• CloudWatch: Know What Your App Is Doing

  … application logs Write structured logs to stdout from containers or Lambda. Include a request ID, level, operation, and …

• AWS Security Building Blocks

  … a Secrets Manager secret called academy/shop/database , containing: json {"username":"shop app","password":"replace-with-real-secret …

• Serverless: Lambda and API Gateway

  … 200 and a JSON string containing Cloud Basics. Test id = "999" for 404 and missing path parameters for …

• VPC Networking Without the Confusion

  … CIDR suffixes describe the network portion of an address: /24 contains 256 total IPv4 addresses. AWS reserves five …

• Design a Logging and Monitoring Platform

  … Logs contain detail but can explode in volume. Traces sample a subset of requests. Do not put unbounded …

• Your Practical Kubernetes Workflow

  … permissions the app needs (least-privilege RBAC). - Run containers as a non-root user where possible. - Keep secrets …

• Terraform: Start Here

  … a separate deployment pipeline to publish a new container image. Your first checkpoint Explain configuration, state, and plan …

• Database Relations & Foreign Keys

  … an order belongs to one customer; an order contains many items; a student may take many courses. Good …