Amazon Route 53 Essentials

# Create Public Hosted Zone
aws route53 create-hosted-zone \
    --name myapp.com \
    --caller-reference $(date +%s) \
    --hosted-zone-config Comment="Production domain"

# Create Private Hosted Zone (only accessible from VPC)
aws route53 create-hosted-zone \
    --name internal.myapp.local \
    --vpc VPCRegion=sa-east-1,VPCId=vpc-xxxxx \
    --caller-reference $(date +%s) \
    --hosted-zone-config PrivateZone=true

# Create Health Check (HTTP/HTTPS endpoint)
aws route53 create-health-check \
    --caller-reference $(date +%s) \
    --health-check-config \
        Protocol=HTTPS,\
        FullyQualifiedDomainName=myapp-lb.sa-east-1.elb.amazonaws.com,\
        Port=443,\
        ResourcePath=/health,\
        Type=HTTPS,\
        RequestInterval=30,\
        FailureThreshold=3

# Create Health Check based on CloudWatch Alarm
aws route53 create-health-check \
    --caller-reference $(date +%s) \
    --health-check-config \
        Type=CLOUDWATCH_METRIC,\
        AlarmIdentifier={Region=sa-east-1,Name=HighCPUAlarm},\
        InsufficientDataHealthStatus=Healthy

# Create ALIAS record pointing to ALB (Simple Routing)
cat > create-alias-record.json << 'EOF'
{
  "Changes": [{
    "Action": "CREATE",
    "ResourceRecordSet": {
      "Name": "myapp.com",
      "Type": "A",
      "AliasTarget": {
        "HostedZoneId": "Z2P70J7HTTTPLU",
        "DNSName": "myapp-lb-123.sa-east-1.elb.amazonaws.com",
        "EvaluateTargetHealth": true
      }
    }
  }]
}
EOF

aws route53 change-resource-record-sets \
    --hosted-zone-id Z0123456789ABC \
    --change-batch file://create-alias-record.json

# Create record with Failover Routing (PRIMARY)
cat > failover-primary.json << 'EOF'
{
  "Changes": [{
    "Action": "CREATE",
    "ResourceRecordSet": {
      "Name": "myapp.com",
      "Type": "A",
      "SetIdentifier": "Primary-SaoPaulo",
      "Failover": "PRIMARY",
      "HealthCheckId": "abc123-healthcheck-id",
      "AliasTarget": {
        "HostedZoneId": "Z2P70J7HTTTPLU",
        "DNSName": "myapp-lb-saopaulo.sa-east-1.elb.amazonaws.com",
        "EvaluateTargetHealth": true
      }
    }
  }]
}
EOF

aws route53 change-resource-record-sets \
    --hosted-zone-id Z0123456789ABC \
    --change-batch file://failover-primary.json

# Create record with Weighted Routing (A/B testing - 80/20)
cat > weighted-stable.json << 'EOF'
{
  "Changes": [{
    "Action": "CREATE",
    "ResourceRecordSet": {
      "Name": "api.myapp.com",
      "Type": "A",
      "SetIdentifier": "Stable-v1.0",
      "Weight": 80,
      "TTL": 60,
      "ResourceRecords": [{"Value": "18.231.1.10"}]
    }
  }]
}
EOF

# Create record with Latency-Based Routing
cat > latency-saopaulo.json << 'EOF'
{
  "Changes": [{
    "Action": "CREATE",
    "ResourceRecordSet": {
      "Name": "myapp.com",
      "Type": "A",
      "SetIdentifier": "Latency-SaoPaulo",
      "Region": "sa-east-1",
      "HealthCheckId": "abc123-saopaulo",
      "AliasTarget": {
        "HostedZoneId": "Z2P70J7HTTTPLU",
        "DNSName": "myapp-lb-saopaulo.sa-east-1.elb.amazonaws.com",
        "EvaluateTargetHealth": false
      }
    }
  }]
}
EOF

# Create record with Geolocation Routing
cat > geo-brazil.json << 'EOF'
{
  "Changes": [{
    "Action": "CREATE",
    "ResourceRecordSet": {
      "Name": "myapp.com",
      "Type": "A",
      "SetIdentifier": "Geo-Brazil",
      "GeoLocation": {
        "CountryCode": "BR"
      },
      "AliasTarget": {
        "HostedZoneId": "Z2P70J7HTTTPLU",
        "DNSName": "myapp-lb-saopaulo.sa-east-1.elb.amazonaws.com",
        "EvaluateTargetHealth": true
      }
    }
  }]
}
EOF

# List all Hosted Zones
aws route53 list-hosted-zones

# View details of a specific Hosted Zone
aws route53 get-hosted-zone --id Z0123456789ABC

# List all records in a Hosted Zone
aws route53 list-resource-record-sets \
    --hosted-zone-id Z0123456789ABC

# List records filtering by name
aws route53 list-resource-record-sets \
    --hosted-zone-id Z0123456789ABC \
    --query "ResourceRecordSets[?Name=='myapp.com.']"

# List Health Checks
aws route53 list-health-checks

# View current status of a Health Check
aws route53 get-health-check-status \
    --health-check-id abc123-healthcheck-id

# View Health Check details
aws route53 get-health-check \
    --health-check-id abc123-healthcheck-id

# Get Name Servers of a Hosted Zone
aws route53 get-hosted-zone --id Z0123456789ABC \
    --query 'DelegationSet.NameServers[]' \
    --output table

# Update existing record (UPSERT = create or update)
cat > update-record.json << 'EOF'
{
  "Changes": [{
    "Action": "UPSERT",
    "ResourceRecordSet": {
      "Name": "myapp.com",
      "Type": "A",
      "TTL": 300,
      "ResourceRecords": [{"Value": "18.231.2.20"}]
    }
  }]
}
EOF

aws route53 change-resource-record-sets \
    --hosted-zone-id Z0123456789ABC \
    --change-batch file://update-record.json

# Change TTL of a record
cat > change-ttl.json << 'EOF'
{
  "Changes": [{
    "Action": "UPSERT",
    "ResourceRecordSet": {
      "Name": "api.myapp.com",
      "Type": "A",
      "TTL": 60,
      "ResourceRecords": [{"Value": "18.231.1.10"}]
    }
  }]
}
EOF

# Update Health Check (change interval)
aws route53 update-health-check \
    --health-check-id abc123-healthcheck-id \
    --health-check-version 1 \
    --health-threshold 2

# Temporarily disable a Health Check (testing failover)
aws route53 update-health-check \
    --health-check-id abc123-healthcheck-id \
    --disabled

# Re-enable Health Check
aws route53 update-health-check \
    --health-check-id abc123-healthcheck-id \
    --no-disabled

# Associate additional VPC to Private Hosted Zone
aws route53 associate-vpc-with-hosted-zone \
    --hosted-zone-id Z0123456789ABC \
    --vpc VPCRegion=us-east-1,VPCId=vpc-yyyyy

# Delete record (requires specifying exactly the record)
cat > delete-record.json << 'EOF'
{
  "Changes": [{
    "Action": "DELETE",
    "ResourceRecordSet": {
      "Name": "old.myapp.com",
      "Type": "A",
      "TTL": 300,
      "ResourceRecords": [{"Value": "18.231.1.99"}]
    }
  }]
}
EOF

aws route53 change-resource-record-sets \
    --hosted-zone-id Z0123456789ABC \
    --change-batch file://delete-record.json

# Delete Health Check
aws route53 delete-health-check \
    --health-check-id abc123-healthcheck-id

# Disassociate VPC from Private Hosted Zone
aws route53 disassociate-vpc-from-hosted-zone \
    --hosted-zone-id Z0123456789ABC \
    --vpc VPCRegion=sa-east-1,VPCId=vpc-xxxxx

# Delete Hosted Zone (must be empty except NS and SOA)
aws route53 delete-hosted-zone \
    --id Z0123456789ABC

# Test DNS resolution with dig
dig myapp.com

# Test specifically against Route53 Name Servers
dig @ns-123.awsdns-45.com myapp.com

# View recent changes in Hosted Zone
aws route53 list-resource-record-sets \
    --hosted-zone-id Z0123456789ABC \
    --query 'ResourceRecordSets[*].[Name,Type,TTL]' \
    --output table

# Verify DNS change status
aws route53 get-change --id /change/C0123456789ABC

# Test health check manually
curl -I https://myapp-lb.sa-east-1.elb.amazonaws.com/health

Infrastructure:
- 1 Hosted Zone (myapp.com)
- 2 regions (sa-east-1 PRIMARY, us-east-1 SECONDARY)
- 2 Health Checks (one per region, 30s interval)
- 5M queries/month (80% ALIAS to ALB, 20% CNAME subdomains)
- Latency-based routing on some subdomains (1M queries/month)

Monthly costs:
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
Hosted Zone:               $0.50
Health Checks (2 × $0.50): $1.00
ALIAS Queries (4M):        $0.00  ← FREE
Standard Queries (1M):     $0.40
Latency Queries (1M):      $0.60
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
TOTAL:                     $2.50/month

# AVOID
CNAME www.myapp.com → myapp.com
CNAME api.myapp.com → api-alb.amazonaws.com
# Each query charges 2x (CNAME + target)

# PREFER
ALIAS www.myapp.com → ALB
ALIAS api.myapp.com → ALB
# Queries FREE

# EXPENSIVE: Separate Hosted Zones
- prod.myapp.com ($0.50/month)
- staging.myapp.com ($0.50/month)
- dev.myapp.com ($0.50/month)
Total: $1.50/month just for zones

# ECONOMICAL: One Hosted Zone with subdomains
- myapp.com ($0.50/month)
  - prod.myapp.com (record)
  - staging.myapp.com (record)
  - dev.myapp.com (record)
Total: $0.50/month

# For critical apps (finance, health):
RequestInterval: 10s  # $1.00/month
FailureThreshold: 2   # Failover in ~20s

# For standard apps:
RequestInterval: 30s  # $0.50/month
FailureThreshold: 3   # Failover in ~90s

# Savings: 50% per health check

# Simple/Failover: $0.40/1M queries
# For most cases

# Latency-based: $0.60/1M queries (+50%)
# Only if you really optimize global latency

# Geolocation: $0.70/1M queries (+75%)
# Only for strict compliance or localization