smom-dbis-138/docs/deployment/DEPLOYMENT_COMPARISON.md

Deployment Comparison: AKS vs VM/VMSS

Overview

This document compares AKS (Azure Kubernetes Service) deployment with VM/VMSS (Virtual Machine/Virtual Machine Scale Set) deployment for the Besu network.

AKS Deployment

Advantages

1. Kubernetes Orchestration

   • Automatic pod scheduling
   • Service discovery
   • Load balancing
   • Rolling updates
   • Self-healing

2. Auto-scaling

   • Horizontal Pod Autoscaler (HPA)
   • Cluster Autoscaler
   • Automatic scaling based on metrics

3. Resource Management

   • Resource quotas
   • Limit ranges
   • Resource requests and limits
   • Namespace isolation

4. Service Mesh

   • Can integrate with service mesh (Istio, Linkerd)
   • Advanced traffic management
   • Security policies

5. Monitoring Integration

   • Prometheus operator
   • Grafana dashboards
   • ServiceMonitors
   • Log aggregation

Disadvantages

1. Complexity

   • Requires Kubernetes expertise
   • More components to manage
   • Steeper learning curve

2. Cost

   • Control plane costs (~$73/month)
   • Additional overhead
   • More resources needed

3. Setup Time

   • More initial setup
   • Configuration complexity
   • More moving parts

VM/VMSS Deployment

Advantages

1. Simplicity

   • Direct Docker deployment
   • Easier to understand
   • Less abstraction
   • Faster setup

2. Cost

   • No control plane costs
   • Pay only for VMs
   • Lower overhead
   • More predictable costs

3. Control

   • Full VM access
   • Direct Docker control
   • Custom configurations
   • Easier troubleshooting

4. Multi-Region

   • Easier to deploy across regions
   • Direct VM management
   • Simpler networking

5. Flexibility

   • Custom VM configurations
   • Different OS options
   • Custom init scripts
   • Direct storage access

Disadvantages

1. Manual Scaling

   • Manual VM scaling
   • No automatic scaling
   • Manual load balancing
   • Manual updates

2. No Service Discovery

   • Manual IP management
   • Static configuration
   • Manual DNS setup
   • No automatic health checks

3. Updates

   • Manual rolling updates
   • Manual configuration updates
   • Manual key rotation
   • More operational overhead

4. Monitoring

   • Manual monitoring setup
   • Less integrated
   • More configuration needed
   • Manual alerting

Comparison Table

Feature	AKS	VM/VMSS
Orchestration	✅ Kubernetes	❌ Manual
Auto-scaling	✅ HPA/Cluster Autoscaler	❌ Manual
Service Discovery	✅ Kubernetes Services	❌ Manual
Load Balancing	✅ Kubernetes Services	⚠️ Manual/Application Gateway
Rolling Updates	✅ Kubernetes Deployments	❌ Manual
Self-healing	✅ Kubernetes	❌ Manual
Resource Management	✅ Kubernetes	⚠️ Manual
Monitoring	✅ Integrated	⚠️ Manual setup
Cost	⚠️ Higher (control plane)	✅ Lower
Complexity	⚠️ Higher	✅ Lower
Setup Time	⚠️ Longer	✅ Shorter
Flexibility	⚠️ Limited to K8s	✅ Full control
Multi-Region	⚠️ Complex	✅ Easier
Troubleshooting	⚠️ K8s knowledge needed	✅ Direct access

Use Cases

Use AKS When

• Production environment
• Need auto-scaling
• Need service discovery
• Have Kubernetes expertise
• Need advanced features (service mesh, etc.)
• Large scale deployment
• Need rolling updates
• Need self-healing

Use VM/VMSS When

• Development environment
• Small to medium scale
• Cost is a concern
• Simplicity is preferred
• Direct control needed
• Multi-region deployment
• No Kubernetes expertise
• Custom configurations needed

Cost Comparison

AKS Deployment

• Control plane: ~$73/month
• Node pools: VM costs
• Load balancer: ~$25/month
• Total: Higher initial cost

VM/VMSS Deployment

• VMs only: VM costs
• Load balancer: Application Gateway (~$200/month for WAF)
• Total: Lower initial cost (no control plane)

Recommendations

For Production

Recommended: AKS

• Better orchestration
• Auto-scaling
• Service discovery
• Self-healing
• Better monitoring integration

For Development

Recommended: VM/VMSS

• Simpler setup
• Lower cost
• Faster deployment
• Easier troubleshooting

For Multi-Region

Recommended: VM/VMSS

• Easier to deploy
• Direct VM management
• Simpler networking
• Lower complexity

Hybrid Approach

You can also use a hybrid approach:

1. Validators on VMs: More control, lower cost
2. RPC nodes on AKS: Auto-scaling, service discovery
3. Sentries on VMs: Simpler, direct control

Migration Path

From VM to AKS

1. Export VM configurations
2. Create Kubernetes manifests
3. Deploy to AKS
4. Migrate data
5. Switch traffic
6. Decommission VMs

From AKS to VM

1. Export Kubernetes configurations
2. Create VM deployment scripts
3. Deploy VMs
4. Migrate data
5. Switch traffic
6. Decommission AKS cluster

Conclusion

Both deployment methods have their advantages. Choose based on your requirements:

• AKS: Better for production, auto-scaling, service discovery
• VM/VMSS: Better for development, cost-effective, simpler

The project supports both deployment methods, so you can choose based on your needs.

References

• AKS Documentation
• VM Documentation
• VMSS Documentation
• Deployment Guide
• VM Deployment Guide