Inhaltsverzeichnis

Runbook: Renew Certificate

Duration: ~10 minutes
Role: Security Admin
Frequency: Every 90 days (Let's Encrypt) or annually

Renewal of TLS certificate for the Data Gateway.

Workflow

flowchart TD A[Expiry warning] --> B{Certificate type?} B -->|Let's Encrypt| C[certbot renew] B -->|Internal CA| D[Request new certificate] B -->|Commercial| E[Renew at provider] C --> F[Replace certificate] D --> F E --> F F --> G[Restart Gateway] G --> H[Test HTTPS] H --> I{OK?} I -->|Yes| J[Done] I -->|No| K[Restore old certificate] style J fill:#e8f5e9 style K fill:#ffebee

1. Check Expiry

# Check current certificate
openssl s_client -connect gateway.example.com:443 -servername gateway.example.com 2>/dev/null | \
    openssl x509 -noout -dates
 
# Days until expiry
echo | openssl s_client -connect gateway.example.com:443 2>/dev/null | \
    openssl x509 -noout -enddate | \
    cut -d= -f2 | \
    xargs -I {} bash -c 'echo "Days until expiry: $(( ($(date -d "{}" +%s) - $(date +%s)) / 86400 ))"'

2a. Renew Let's Encrypt

# Automatic (if certbot correctly configured)
sudo certbot renew
 
# With pre/post hook for Gateway
sudo certbot renew \
    --pre-hook "systemctl stop data-gateway" \
    --post-hook "systemctl start data-gateway"
 
# Dry run (without actual renewal)
sudo certbot renew --dry-run

Automation via cron: 

# /etc/cron.d/certbot-gateway
0 3 * * * root certbot renew --quiet --post-hook "systemctl reload data-gateway"

2b. Renew Internal CA

# Create CSR
openssl req -new -key gateway.key -out gateway.csr \
    -subj "/CN=gateway.example.com/O=Example Corp"
 
# Send CSR to CA (e.g., via PQ Crypto)
# -> New certificate: gateway-new.crt

See: PQ Crypto: Renew Certificate

2c. Commercial Certificate

1. Log in at provider (DigiCert, GlobalSign, etc.) 2. Request renewal 3. Upload CSR or generate new 4. Complete validation 5. Download new certificate

3. Backup Old Certificate

# Create backup
cp /opt/data-gateway/certs/gateway.pfx /opt/data-gateway/certs/gateway.pfx.bak.$(date +%Y%m%d)
 
# Or for PEM
cp /opt/data-gateway/certs/cert.pem /opt/data-gateway/certs/cert.pem.bak.$(date +%Y%m%d)

4. Install New Certificate

# PEM format
sudo cp new-cert.pem /opt/data-gateway/certs/cert.pem
sudo cp new-key.pem /opt/data-gateway/certs/key.pem
sudo chmod 600 /opt/data-gateway/certs/*.pem
 
# PFX format
sudo cp new-gateway.pfx /opt/data-gateway/certs/gateway.pfx
sudo chmod 600 /opt/data-gateway/certs/gateway.pfx

5. Restart Gateway

# Linux
sudo systemctl restart data-gateway
 
# Windows
Restart-Service -Name "DataGateway"
 
# Docker
docker restart gateway
 
# Kubernetes (Rolling Update)
kubectl rollout restart deployment/data-gateway -n data-gateway

6. Verify

# New certificate active?
echo | openssl s_client -connect gateway.example.com:443 2>/dev/null | \
    openssl x509 -noout -subject -dates
 
# Health Check
curl https://gateway.example.com/health
 
# Full SSL test
openssl s_client -connect gateway.example.com:443 -servername gateway.example.com

7. Rollback (if needed)

# Restore backup
sudo cp /opt/data-gateway/certs/gateway.pfx.bak.20241215 /opt/data-gateway/certs/gateway.pfx
 
# Restart Gateway
sudo systemctl restart data-gateway
 
# Verify
curl https://gateway.example.com/health

8. Checklist

# Check Done
———-——
1 Old certificate backed up [ ]
2 New certificate valid [ ]
3 Hostnames match [ ]
4 Certificate installed [ ]
5 Gateway restarted [ ]
6 HTTPS working [ ]
7 Monitoring notified [ ]

Troubleshooting

Problem Cause Solution
—————-———-
Certificate mismatch Key doesn't match Regenerate key
Chain incomplete Intermediate missing Add chain file
Permission denied Wrong permissions chmod 600
Gateway won't start Wrong password Check appsettings.json

Automatic Monitoring

Prometheus alert for certificate expiry: 

- alert: GatewayCertExpiringSoon
  expr: |
    (probe_ssl_earliest_cert_expiry{job="gateway-tls"} - time()) / 86400 < 14
  for: 1h
  labels:
    severity: warning
  annotations:
    summary: "Gateway certificate expiring soon"
    description: "Certificate expires in {{ $value | humanize }} days."

« <- Set Up TLS | -> Firewall Rules »

Wolfgang van der Stille @ EMSR DATA d.o.o. - Data Gateway Professional

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