🌐 Cluster Management - georgi-dev215/openvpn-web-manager GitHub Wiki

Cluster Management

Advanced multi-server cluster management for high availability and load distribution.

Overview

The Cluster Management system enables you to:

Manage multiple OpenVPN servers from a single interface
Distribute client load across servers
Monitor cluster health and performance
Implement automatic failover
Scale your VPN infrastructure

Architecture

┌─────────────────────────────────────────────────┐ │ Master Controller │ │ ┌─────────────────────────────────────────────┐ │ │ │ Web Management Interface │ │ │ └─────────────────────────────────────────────┘ │ ├─────────────────────────────────────────────────┤ │ ┌─────────────┐ ┌─────────────┐ ┌───────────┐ │ │ │ Server 1 │ │ Server 2 │ │ Server N │ │ │ │ (Primary) │ │ (Secondary) │ │ (Worker) │ │ │ └─────────────┘ └─────────────┘ └───────────┘ │ └─────────────────────────────────────────────────┘

Server Management

Adding Servers to Cluster

Prerequisites

# On each server node
- OpenVPN installed and configured
- SSH access enabled
- Python 3.7+ installed
- Network connectivity between servers

Adding a Server

Navigate to Cluster → Servers
Click Add New Server
Configure server details:

Server Configuration:
  server_id: server-01
  server_name: Primary EU Server
  hostname: 10.0.1.100
  public_ip: 203.0.113.10
  ssh_port: 22
  ssh_user: admin
  ssh_key_path: /path/to/private/key
  openvpn_port: 1194
  management_port: 7505
  region: eu-west-1
  capacity: 100
  priority: high

Test connection
Initialize server configuration
Add to cluster pool

Server Roles

Primary Server

Role: Main configuration source
Responsibilities:
- Certificate Authority (CA)
- Configuration templates
- Client database master
High Availability: Can be promoted/demoted

Secondary Servers

Role: Backup and load distribution
Responsibilities:
- Client connection handling
- Local configuration sync
- Health monitoring
Failover: Automatic promotion to primary

Worker Servers

Role: Pure connection handlers
Responsibilities:
- Client VPN connections only
- Minimal configuration
- Scale-out capacity

Server Status Monitoring

Health Checks

Health Check Parameters:
- CPU Usage: < 80%
- Memory Usage: < 85%
- Disk Space: > 15% free
- OpenVPN Service: Active
- Network Connectivity: Online
- Response Time: < 200ms

Status Indicators

🟢 Online: Server operational and accepting connections
🟡 Warning: Performance issues detected
🔴 Critical: Server unavailable or failing
⚫ Offline: Server not responding
🔧 Maintenance: Manually set maintenance mode

Load Balancing

Distribution Strategies

Round Robin

# Equal distribution across all available servers
client_assignment = {
    'strategy': 'round_robin',
    'servers': ['server-01', 'server-02', 'server-03'],
    'current_index': 0
}

Weighted Distribution

# Based on server capacity and performance
server_weights = {
    'server-01': 40,  # High capacity
    'server-02': 35,  # Medium capacity  
    'server-03': 25   # Lower capacity
}

Geographic Distribution

# Route clients to nearest server
geo_routing = {
    'europe': ['eu-server-01', 'eu-server-02'],
    'america': ['us-server-01', 'us-server-02'],
    'asia': ['asia-server-01']
}

Performance-Based

# Real-time server performance metrics
performance_routing = {
    'metrics': ['cpu_usage', 'memory_usage', 'connection_count'],
    'update_interval': 60,  # seconds
    'rebalance_threshold': 0.8
}

Client Assignment

Automatic Assignment

New Client Registration:
- Evaluate server capacity
- Apply routing strategy
- Generate server-specific configuration
- Assign client to optimal server
Dynamic Rebalancing:
- Monitor server loads
- Identify overloaded servers
- Migrate clients to less loaded servers
- Update client configurations

Manual Assignment

Go to Clients → Cluster Assignment
Select client(s)
Choose target server
Apply assignment
Generate new configuration

High Availability & Failover

Automatic Failover

Failover Triggers

Failover Conditions:
  - Server unresponsive for > 3 minutes
  - CPU usage > 95% for > 5 minutes
  - Memory usage > 95% for > 5 minutes
  - OpenVPN service stopped
  - Network connectivity lost

Failover Process

Detection: Health monitoring detects failure
Verification: Multiple checks confirm failure
Client Migration: Active connections redirected
Configuration Update: DNS/routing updates
Notification: Alerts sent to administrators

Manual Failover

# Emergency failover command
./cluster-manager.py failover --from server-01 --to server-02

# Maintenance mode
./cluster-manager.py maintenance --server server-01 --enable

# Server promotion
./cluster-manager.py promote --server server-02 --to-primary

Configuration Synchronization

Configuration Management

Centralized Configuration

Synchronized Elements:
  - OpenVPN server configuration
  - Client certificates and keys
  - Network routing rules
  - Security policies
  - Access control lists

Sync Process

Master Configuration: Primary server holds authoritative config
Change Detection: Monitor configuration changes
Distribution: Push changes to all cluster servers
Validation: Verify configuration integrity
Activation: Apply changes with rollback capability

Certificate Synchronization

CA Management

# Certificate Authority sync
- Root CA certificate
- Intermediate certificates  
- Client certificates
- Certificate Revocation List (CRL)
- Private keys (encrypted)

Sync Schedule

Real-time: Critical security changes
Scheduled: Regular configuration sync (hourly)
On-demand: Manual administrator triggers

Monitoring & Analytics

Cluster Metrics

Performance Metrics

cluster_metrics = {
    'total_servers': 5,
    'online_servers': 4,
    'total_clients': 150,
    'active_connections': 89,
    'avg_cpu_usage': 45.2,
    'avg_memory_usage': 62.8,
    'total_bandwidth': '2.5 Gbps',
    'response_time_avg': 125  # ms
}

Server Comparison

Server	Status	Clients	CPU	Memory	Bandwidth
EU-01	🟢 Online	25/50	45%	60%	512 Mbps
EU-02	🟢 Online	22/50	38%	55%	445 Mbps
US-01	🟡 Warning	30/50	78%	82%	678 Mbps
US-02	🟢 Online	12/50	25%	35%	234 Mbps

Real-time Dashboard

Cluster Overview Widget

Total servers and status distribution
Active connections across cluster
Aggregate performance metrics
Recent events and alerts

Server Grid View

Individual server status cards
Quick actions (maintenance, restart, etc.)
Performance sparklines
Connection distribution

Troubleshooting

Common Issues

Server Communication Problems

# Test SSH connectivity
ssh -p 22 admin@server-ip "echo 'Connection OK'"

# Check OpenVPN management interface
telnet server-ip 7505

# Verify network routing
traceroute server-ip

Configuration Sync Failures

# Manual configuration sync
./cluster-manager.py sync --server server-01 --force

# Check sync logs
tail -f /var/log/openvpn-cluster/sync.log

# Validate configuration
./cluster-manager.py validate --server server-01

Load Balancing Issues

# Check client distribution
./cluster-manager.py status --show-distribution

# Rebalance clients manually
./cluster-manager.py rebalance --strategy performance

# View assignment history
./cluster-manager.py history --client client-name

Diagnostic Commands

# Cluster health check
./cluster-manager.py health --all

# Performance report
./cluster-manager.py report --performance --last-24h

# Connection analysis
./cluster-manager.py analyze --connections

# Export cluster configuration
./cluster-manager.py export --config --output cluster-backup.json

Best Practices

Deployment Recommendations

Server Placement

Geographic Distribution: Servers in different regions
Network Diversity: Multiple ISPs/data centers
Capacity Planning: 20-30% overhead for failover

Security Considerations

SSH Key Management: Unique keys per server
Network Segmentation: Isolated management network
Certificate Security: Encrypted key storage

Performance Optimization

Server Sizing

Small Deployment (< 50 clients):
  - 2 vCPU, 2GB RAM
  - 20GB SSD storage
  - 100 Mbps network

Medium Deployment (50-200 clients):
  - 4 vCPU, 4GB RAM
  - 50GB SSD storage
  - 500 Mbps network

Large Deployment (200+ clients):
  - 8+ vCPU, 8GB+ RAM
  - 100GB+ SSD storage
  - 1+ Gbps network

Monitoring Intervals

Health Checks: Every 60 seconds
Performance Metrics: Every 5 minutes
Configuration Sync: Every hour
Log Rotation: Daily

Maintenance Procedures

Planned Maintenance

Enable maintenance mode
Drain client connections
Perform updates/changes
Validate functionality
Return to service
Monitor for issues

Emergency Procedures

Immediate failover activation
Client notification (if required)
Root cause analysis
Temporary fixes
Permanent resolution
Post-incident review