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Tuning

Fine-tune BIND9 and Kubernetes parameters for optimal performance.

BIND9 Tuning

Query Performance

# Future enhancement - BIND9 tuning via Bind9Instance spec
spec:
  config:
    tuning:
      maxCacheSize: "512M"
      maxCacheTTL: 86400
      recursiveClients: 1000

Zone Transfer Tuning

  • Concurrent transfers: transfers-in, transfers-out
  • Transfer timeout: Adjust for large zones
  • Compression: Enable for faster transfers

Kubernetes Tuning

Pod Resources

Right-size based on load:

# Light load
resources:
  requests: {cpu: "100m", memory: "128Mi"}
  limits: {cpu: "500m", memory: "512Mi"}

# Medium load
resources:
  requests: {cpu: "500m", memory: "512Mi"}
  limits: {cpu: "2000m", memory: "2Gi"}

# Heavy load
resources:
  requests: {cpu: "2000m", memory: "2Gi"}
  limits: {cpu: "4000m", memory: "4Gi"}

HPA (Horizontal Pod Autoscaling)

apiVersion: autoscaling/v2
kind: HorizontalPodAutoscaler
metadata:
  name: bind9-hpa
spec:
  scaleTargetRef:
    apiVersion: apps/v1
    kind: Deployment
    name: primary-dns
  minReplicas: 2
  maxReplicas: 10
  metrics:
  - type: Resource
    resource:
      name: cpu
      target:
        type: Utilization
        averageUtilization: 70

Node Affinity

Place DNS pods on optimized nodes:

affinity:
  nodeAffinity:
    requiredDuringSchedulingIgnoredDuringExecution:
      nodeSelectorTerms:
      - matchExpressions:
        - key: workload-type
          operator: In
          values:
          - dns

Network Tuning

Service Type

Consider NodePort or LoadBalancer for external access:

apiVersion: v1
kind: Service
spec:
  type: LoadBalancer  # Or NodePort
  externalTrafficPolicy: Local  # Preserve source IP

DNS Caching

Adjust TTL values:

# Short TTL for dynamic records
spec:
  ttl: 60  # 1 minute

# Long TTL for static records
spec:
  ttl: 86400  # 24 hours

OS-Level Tuning

File Descriptors

Increase limits for high query volume:

# In pod security context (future enhancement)
securityContext:
  limits:
    nofile: 65536

Network Buffers

Optimize for DNS traffic (node-level):

# Increase UDP buffer sizes
sysctl -w net.core.rmem_max=8388608
sysctl -w net.core.wmem_max=8388608

Monitoring Tuning Impact

# Before tuning - baseline
kubectl top pods -n dns-system
time dig @$SERVICE_IP example.com

# Apply tuning
kubectl apply -f tuned-config.yaml

# After tuning - compare
kubectl top pods -n dns-system
time dig @$SERVICE_IP example.com

Tuning Checklist

  • Right-sized pod resources
  • Optimal replica count
  • HPA configured
  • Appropriate TTL values
  • Network policies optimized
  • Node placement configured
  • Monitoring enabled
  • Performance tested

Next Steps