Cloud Architecture Mistakes I Made So You Don't Have To

Mistake 1: Over-Engineering from Day 1 ## Mistake 2: Single Availability Zone ## Mistake 3: No Cost Alerts ## Mistake 4: Hardcoded Credentials ## Mistake 5: No Infrastructure as Code ## Mistake 6: Ignoring Reserved Instances ## Mistake 7: Not Tagging Resources ## AWS vs Azure vs GCP: Quick Take ## Learn More I've been building cloud infrastructure for 5+ years. Here are the expensive lessons I learned—so you can skip the pain. My first startup? I built a Kubernetes cluster for 50 users. What I should've done: Start with managed services. PaaS beats IaaS for 90% of early-stage apps. Kubernetes can wait until you actually need it. "It won't go down." Famous last words. AWS regions have multiple Availability Zones (AZs). If you're in one AZ and it has issues, you're offline. Fix: Deploy across at least 2 AZs. Most managed services do this automatically. I once woke up to a $3,000 AWS bill. A misconfigured Lambda was running in an infinite loop. Fix: Set up billing alerts immediately: I've seen production keys committed to public GitHub repos. Bots scan for these 24/7. Clicking through the AWS console works until: Fix: Terraform or AWS CDK from the start: I paid on-demand rates for 2 years. Reserved Instances would've saved 40%. If your workload is predictable, reserve it. Six months later: "What is this EC2 instance? Who created it? Can I delete it?" For most startups: AWS. The ecosystem is unmatched. I've written a complete Cloud Architecture guide covering: 👉 Cloud Architecture Complete Guide What cloud mistakes have you made? Share in the comments—we've all been there � Templates let you quickly answer FAQs or store snippets for re-use. Are you sure you want to hide this comment? It will become hidden in your post, but will still be visible via the comment's permalink. Hide child comments as well For further actions, you may consider blocking this person and/or reporting abuse CODE_BLOCK: MVP Stack (0-10k users): ├── Vercel/Railway/Render (App) ├── Managed Postgres (Supabase/PlanetScale) ├── S3 for files └── CloudFront CDN Enter fullscreen mode Exit fullscreen mode CODE_BLOCK: MVP Stack (0-10k users): ├── Vercel/Railway/Render (App) ├── Managed Postgres (Supabase/PlanetScale) ├── S3 for files └── CloudFront CDN CODE_BLOCK: MVP Stack (0-10k users): ├── Vercel/Railway/Render (App) ├── Managed Postgres (Supabase/PlanetScale) ├── S3 for files └── CloudFront CDN COMMAND_BLOCK: # AWS CLI - Create a billing alarm aws cloudwatch put-metric-alarm \ --alarm-name "BillingAlarm" \ --metric-name "EstimatedCharges" \ --namespace "AWS/Billing" \ --threshold 100 \ --comparison-operator GreaterThanThreshold Enter fullscreen mode Exit fullscreen mode COMMAND_BLOCK: # AWS CLI - Create a billing alarm aws cloudwatch put-metric-alarm \ --alarm-name "BillingAlarm" \ --metric-name "EstimatedCharges" \ --namespace "AWS/Billing" \ --threshold 100 \ --comparison-operator GreaterThanThreshold COMMAND_BLOCK: # AWS CLI - Create a billing alarm aws cloudwatch put-metric-alarm \ --alarm-name "BillingAlarm" \ --metric-name "EstimatedCharges" \ --namespace "AWS/Billing" \ --threshold 100 \ --comparison-operator GreaterThanThreshold CODE_BLOCK: // 🚨 NEVER DO THIS const AWS_KEY = "AKIAIOSFODNN7EXAMPLE"; Enter fullscreen mode Exit fullscreen mode CODE_BLOCK: // 🚨 NEVER DO THIS const AWS_KEY = "AKIAIOSFODNN7EXAMPLE"; CODE_BLOCK: // 🚨 NEVER DO THIS const AWS_KEY = "AKIAIOSFODNN7EXAMPLE"; COMMAND_BLOCK: # Terraform example resource "aws_instance" "web" { ami = "ami-0c55b159cbfafe1f0" instance_type = "t3.micro" tags = { Name = "Production-Web" Environment = "prod" } } Enter fullscreen mode Exit fullscreen mode COMMAND_BLOCK: # Terraform example resource "aws_instance" "web" { ami = "ami-0c55b159cbfafe1f0" instance_type = "t3.micro" tags = { Name = "Production-Web" Environment = "prod" } } COMMAND_BLOCK: # Terraform example resource "aws_instance" "web" { ami = "ami-0c55b159cbfafe1f0" instance_type = "t3.micro" tags = { Name = "Production-Web" Environment = "prod" } } - Use environment variables - AWS IAM roles (no keys needed on EC2/Lambda) - Secrets Manager for sensitive config - You need to replicate in another region - Someone accidentally deletes something - You forget what you configured - On-demand t3.medium: ~$30/month - 1-year reserved: ~$18/month (40% savings) - 3-year reserved: ~$12/month (60% savings) - Environment: prod/staging/dev - Owner: team or person - Project: which project it belongs to - CostCenter: for billing - Detailed AWS vs Azure vs GCP comparison - Architecture patterns (monolith → microservices) - Security fundamentals - Cost optimization strategies - Scaling for growth