Chapter 1: Custom Domains¶

Progress Indicator¶

Module 3: Going Live
├─ Chapter 1: Custom Domains     ← YOU ARE HERE
├─ Chapter 2: Environment Secrets
└─ Chapter 3: Monitoring & Logs

Learning Objectives¶

By the end of this chapter, you will: - Understand DNS concepts and how domains work - Configure DNS records for your domain - Connect your domain to your EgyGeeks application using Traefik - Test and verify your domain configuration

Prerequisites¶

• A domain registered with any registrar (GoDaddy, Namecheap, etc.)
• An application already deployed and running
• Access to your domain registrar's control panel
• Your application's public IP address or CNAME target

Step 1: Understand DNS Basics¶

What is DNS?¶

DNS (Domain Name System) translates human-readable domain names into IP addresses. When someone visits myapp.com, DNS tells their browser where to find your application.

DNS Record Types¶

For connecting your domain to EgyGeeks, you'll use:

Step 2: Get Your Application's Target¶

Find Your Public IP or CNAME¶

First, determine what your DNS record should point to. This depends on your deployment:

If using a cloud provider (AWS, Linode, DigitalOcean):

# Your IP address is usually shown in the control panel
# Example: 192.0.2.10

If using a load balancer or reverse proxy:

# You'll get a CNAME target
# Example: lb-1234.example.com

Quick Check¶

# Test your application is accessible at its current address
curl http://<your-ip-or-host>

# You should see your application responding

Step 3: Configure DNS Records¶

Access Your Domain Registrar¶

1. Log in to your domain registrar (GoDaddy, Namecheap, Cloudflare, etc.)
2. Find the DNS or Name Servers section
3. Look for DNS Records or Zone File management

Add DNS Records¶

For the root domain (myapp.com):

Using an A Record: - Type: A - Name/Host: @ or leave blank - Value: Your application's IP address - TTL: 3600 (1 hour) - can be changed later

@ → 192.0.2.10

For www subdomain (www.myapp.com):

Using a CNAME Record: - Type: CNAME - Name/Host: www - Value: myapp.com - TTL: 3600

www → myapp.com

DNS Configuration Example¶

Domain: myapp.com
Registrar: Namecheap

Records:
┌─────────────┬──────────┬───────────────────┐
│ Type        │ Name     │ Value             │
├─────────────┼──────────┼───────────────────┤
│ A           │ @        │ 192.0.2.10        │
│ CNAME       │ www      │ myapp.com         │
└─────────────┴──────────┴───────────────────┘

Step 4: Configure Traefik Labels¶

Traefik is the reverse proxy that handles routing to your application. You need to add labels to tell Traefik about your domain.

Update docker-compose.yml¶

Add these labels to your application service:

services:
  myapp:
    image: your-image:latest
    labels:
      # Enable Traefik for this service
      - "traefik.enable=true"

      # HTTP routing
      - "traefik.http.routers.myapp.rule=Host(`myapp.com`) || Host(`www.myapp.com`)"
      - "traefik.http.routers.myapp.entrypoints=web"

      # Port where your app listens
      - "traefik.http.services.myapp.loadbalancer.server.port=3000"

      # HTTPS/SSL (we'll configure this next)
      - "traefik.http.routers.myapp-secure.rule=Host(`myapp.com`) || Host(`www.myapp.com`)"
      - "traefik.http.routers.myapp-secure.entrypoints=websecure"
      - "traefik.http.routers.myapp-secure.tls.certresolver=letsencrypt"
      - "traefik.http.services.myapp-secure.loadbalancer.server.port=3000"

Full docker-compose.yml Example¶

version: '3.8'

services:
  traefik:
    image: traefik:v2.10
    command:
      - "--api.insecure=true"
      - "--providers.docker=true"
      - "--providers.docker.exposedbydefault=false"
      - "--entrypoints.web.address=:80"
      - "--entrypoints.websecure.address=:443"
      - "--certificatesresolvers.letsencrypt.acme.httpchallenge=true"
      - "--certificatesresolvers.letsencrypt.acme.httpchallenge.entrypoint=web"
      - "--certificatesresolvers.letsencrypt.acme.email=your-email@example.com"
      - "--certificatesresolvers.letsencrypt.acme.storage=/acme.json"
    ports:
      - "80:80"
      - "443:443"
      - "8080:8080"
    volumes:
      - /var/run/docker.sock:/var/run/docker.sock
      - ./acme.json:/acme.json
    networks:
      - web

  myapp:
    image: your-image:latest
    expose:
      - 3000
    networks:
      - web
    labels:
      - "traefik.enable=true"
      - "traefik.http.routers.myapp.rule=Host(`myapp.com`) || Host(`www.myapp.com`)"
      - "traefik.http.routers.myapp.entrypoints=web"
      - "traefik.http.routers.myapp.middlewares=redirect-to-https"
      - "traefik.http.middlewares.redirect-to-https.redirectscheme.scheme=https"

      - "traefik.http.routers.myapp-secure.rule=Host(`myapp.com`) || Host(`www.myapp.com`)"
      - "traefik.http.routers.myapp-secure.entrypoints=websecure"
      - "traefik.http.routers.myapp-secure.tls.certresolver=letsencrypt"
      - "traefik.http.services.myapp.loadbalancer.server.port=3000"

networks:
  web:
    driver: bridge

Step 5: Deploy with Updated Configuration¶

Apply the Changes¶

# Stop the current deployment
docker-compose down

# Start with the new configuration
docker-compose up -d

# Check Traefik is running
docker-compose logs traefik

Wait for DNS Propagation¶

DNS changes take time to propagate globally (usually 24-48 hours, but can be immediate):

# Check if your domain is resolving
nslookup myapp.com
# or
dig myapp.com

# Should show your IP address

Step 6: Verify Your Configuration¶

Test HTTP Access¶

# Test your domain (may take time to propagate)
curl http://myapp.com

# Test www subdomain
curl http://www.myapp.com

# Follow redirects to see HTTPS
curl -L http://myapp.com

Check Traefik Dashboard¶

http://localhost:8080

You should see: - Your router rules for myapp.com and www.myapp.com - Status showing "200 OK" - SSL certificates being issued

Browser Test¶

Open your browser and navigate to: - http://myapp.com - Should load your application - https://myapp.com - Should work (after SSL certificate is issued) - https://www.myapp.com - Should also work

Troubleshooting¶

Domain Not Resolving¶

Problem: nslookup myapp.com returns "server can't find"

Solutions: - Wait longer for DNS propagation (up to 48 hours) - Check registrar dashboard - confirm A record is set - Clear local DNS cache:

# macOS
sudo dscacheutil -flushcache

# Linux
sudo systemctl restart systemd-resolved

Connection Refused¶

Problem: curl http://myapp.com returns "Connection refused"

Solutions: - Verify application is running: docker-compose ps - Check port 80 is not blocked by firewall - Verify Traefik is running: docker logs traefik-container-name - Check service name matches in docker-compose

SSL Certificate Not Issued¶

Problem: Browser shows "SSL certificate not found"

Solutions: - Wait 5-10 minutes for Let's Encrypt to issue certificate - Check Traefik logs: docker-compose logs traefik - Verify email in Traefik configuration is correct - Check acme.json file exists and is writable: ls -l acme.json

Traefik Labels Not Applied¶

Problem: Domain shows no route in Traefik dashboard

Solutions: - Restart the service: docker-compose restart myapp - Verify labels are in docker-compose.yml with correct indentation - Check labels syntax - use backticks not quotes for domains - Restart Traefik: docker-compose restart traefik

AI Prompts for This Lesson¶

Domain DNS Configuration¶

I'm setting up a custom domain for my EgyGeeks deployment.

My domain: [yourdomain.com]
My app is deployed at IP: 50.3.85.110
I want both root domain and www subdomain to work.

Generate the complete DNS configuration:
1. A records for root domain
2. CNAME records for www subdomain
3. Any required TXT records for verification

Also explain:
- Expected DNS propagation time
- How to verify DNS is working
- Commands to test DNS resolution

I want to host multiple applications on the same server.

Server IP: 50.3.85.110
Domains:
- myapp.com → app service (port 3000)
- api.myapp.com → api service (port 8000)
- admin.myapp.com → admin service (port 4000)

Generate:
1. DNS records for all three domains
2. Complete docker-compose.yml with Traefik labels
3. SSL/HTTPS configuration for each domain

Traefik Configuration¶

Help me configure Traefik for my application.

Domain: [yourdomain.com]
Application port: [3000]
Technology: [Node.js/Python/etc]

Generate Traefik labels for:
1. HTTP routing (both root and www)
2. HTTPS/SSL with Let's Encrypt
3. HTTP to HTTPS redirect
4. Port configuration

Include the complete docker-compose.yml service configuration.

I need to route different subdomains to different services.

Setup:
- app.egygeeks.com → main app (port 3000)
- api.egygeeks.com → API server (port 8000)
- docs.egygeeks.com → documentation (port 8080)

All should:
- Use SSL/HTTPS
- Redirect HTTP to HTTPS
- Auto-renew certificates

Generate the complete Traefik configuration.

SSL Certificate Troubleshooting¶

My custom domain shows SSL errors.

Domain: [yourdomain.com]
Server IP: 50.3.85.110

Output from `docker compose logs traefik | grep letsencrypt`:
[paste logs here]

My Traefik labels from docker-compose.yml:
[paste your labels here]

Browser error:
[describe the SSL error message]

Help me fix the SSL certificate issue. What could be wrong?

My domain isn't pointing to my server.

Domain: [yourdomain.com]
Expected IP: 50.3.85.110

Output from `nslookup yourdomain.com`:
[paste output]

Output from `dig yourdomain.com`:
[paste output]

DNS records in my registrar:
[describe what you see]

How long should I wait? What else can I check?

Connection Issues¶

Getting "Connection refused" when accessing my domain.

Domain: [yourdomain.com]
DNS resolves to: [IP from nslookup]
Expected IP: 50.3.85.110

Output from `docker-compose ps`:
[paste output]

Output from `docker-compose logs traefik | tail -50`:
[paste logs]

Output from `curl http://50.3.85.110`:
[paste output]

What could be blocking the connection?

I've configured my domain but want to verify everything is correct.

Domain: [yourdomain.com]
Server IP: 50.3.85.110

Generate a complete testing checklist:
1. DNS resolution tests
2. HTTP/HTTPS connectivity tests
3. SSL certificate verification
4. Redirect testing (HTTP → HTTPS)
5. www vs non-www testing

Include all commands I should run.

What's Next¶

Congratulations! Your domain is now connected. Next, you need to:

→ Chapter 2: Environment Secrets

Learn how to securely manage environment variables and sensitive data like API keys, database passwords, and authentication tokens.

Help & Support¶

• DNS Issues? Most domain-related problems are DNS propagation delays
• Traefik Questions? Check the Traefik documentation: https://doc.traefik.io/
• Still Stuck? Check our troubleshooting guide or contact support

Need clarification on any step? Feel free to ask in the community forums or check the FAQ section.