quorum-manager

name: quorum-manager
description: Implements dynamic quorum adjustment and intelligent membership management

Quorum Manager

Implements dynamic quorum adjustment and intelligent membership management for distributed consensus protocols.

Core Responsibilities

1. **Dynamic Quorum Calculation**: Adapt quorum requirements based on real-time network conditions 2. **Membership Management**: Handle seamless node addition, removal, and failure scenarios 3. **Network Monitoring**: Assess connectivity, latency, and partition detection 4. **Weighted Voting**: Implement capability-based voting weight assignments 5. **Fault Tolerance Optimization**: Balance availability and consistency guarantees

Technical Implementation

Core Quorum Management System

class QuorumManager {
  constructor(nodeId, consensusProtocol) {
    this.nodeId = nodeId;
    this.protocol = consensusProtocol;
    this.currentQuorum = new Map(); // nodeId -> QuorumNode
    this.quorumHistory = [];
    this.networkMonitor = new NetworkConditionMonitor();
    this.membershipTracker = new MembershipTracker();
    this.faultToleranceCalculator = new FaultToleranceCalculator();
    this.adjustmentStrategies = new Map();
    
    this.initializeStrategies();
  }

  // Initialize quorum adjustment strategies
  initializeStrategies() {
    this.adjustmentStrategies.set('NETWORK_BASED', new NetworkBasedStrategy());
    this.adjustmentStrategies.set('PERFORMANCE_BASED', new PerformanceBasedStrategy());
    this.adjustmentStrategies.set('FAULT_TOLERANCE_BASED', new FaultToleranceStrategy());
    this.adjustmentStrategies.set('HYBRID', new HybridStrategy());
  }

  // Calculate optimal quorum size based on current conditions
  async calculateOptimalQuorum(context = {}) {
    const networkConditions = await this.networkMonitor.getCurrentConditions();
    const membershipStatus = await this.membershipTracker.getMembershipStatus();
    const performanceMetrics = context.performanceMetrics || await this.getPerformanceMetrics();
    
    const analysisInput = {
      networkConditions: networkConditions,
      membershipStatus: membershipStatus,
      performanceMetrics: performanceMetrics,
      currentQuorum: this.currentQuorum,
      protocol: this.protocol,
      faultToleranceRequirements: context.faultToleranceRequirements || this.getDefaultFaultTolerance()
    };
    
    // Apply multiple strategies and select optimal result
    const strategyResults = new Map();
    
    for (const [strategyName, strategy] of this.adjustmentStrategies) {
      try {
        const result = await strategy.calculateQuorum(analysisInput);
        strategyResults.set(strategyName, result);
      } catch (error) {
        console.warn(`Strategy ${strategyName} failed:`, error);
      }
    }
    
    // Select best strategy result
    const optimalResult = this.selectOptimalStrategy(strategyResults, analysisInput);
    
    return {
      recommendedQuorum: optimalResult.quorum,
      strategy: optimalResult.strategy,
      confidence: optimalResult.confidence,
      reasoning: optimalResult.reasoning,
      expectedImpact: optimalResult.expectedImpact
    };
  }

  // Apply quorum changes with validation and rollback capability
  async adjustQuorum(newQuorumConfig, options = {}) {
    const adjustmentId = `adjustment_${Date.now()}`;
    
    try {
      // Validate new quorum configuration
      await this.validateQuorumConfiguration(newQuorumConfig);
      
      // Create adjustment plan
      const adjustmentPlan = await this.createAdjustmentPlan(
        this.currentQuorum, newQuorumConfig
      );
      
      // Execute adjustment with monitoring
      const adjustmentResult = await this.executeQuorumAdjustment(
        adjustmentPlan, adjustmentId, options
      );
      
      // Verify adjustment success
      await this.verifyQuorumAdjustment(adjustmentResult);
      
      // Update current quorum
      this.currentQuorum = newQuorumConfig.quorum;
      
      // Record successful adjustment
      this.recordQuorumChange(adjustmentId, adjustmentResult);
      
      return {
        success: true,
        adjustmentId: adjustmentId,
        previousQuorum: adjustmentPlan.previousQuorum,
        newQuorum: this.currentQuorum,
        impact: adjustmentResult.impact
      };
      
    } catch (error) {
      console.error(`Quorum adjustment failed:`, error);
      
      // Attempt rollback
      await this.rollbackQuorumAdjustment(adjustmentId);
      
      throw error;
    }
  }

  async executeQuorumAdjustment(adjustmentPlan, adjustmentId, options) {
    const startTime = Date.now();
    
    // Phase 1: Prepare nodes for quorum change
    await this.prepareNodesForAdjustment(adjustmentPlan.affectedNodes);
    
    // Phase 2: Execute membership changes
    const membershipChanges = await this.executeMembershipChanges(
      adjustmentPlan.membershipChanges
    );
    
    // Phase 3: Update voting weights if needed
    if (adjustmentPlan.weightChanges.length > 0) {
      await this.updateVotingWeights(adjustmentPlan.weightChanges);
    }
    
    // Phase 4: Reconfigure consensus protocol
    await this.reconfigureConsensusProtocol(adjustmentPlan.protocolChanges);
    
    // Phase 5: Verify new quorum is operational
    const verificationResult = await this.verifyQuorumOperational(adjustmentPlan.newQuorum);
    
    const endTime = Date.now();
    
    return {
      adjustmentId: adjustmentId,
      duration: endTime - startTime,
      membershipChanges: membershipChanges,
      verificationResult: verificationResult,
      impact: await this.measureAdjustmentImpact(startTime, endTime)
    };
  }
}

Network-Based Quorum Strategy

class NetworkBasedStrategy {
  constructor() {
    this.networkAnalyzer = new NetworkAnalyzer();
    this.connectivityMatrix = new ConnectivityMatrix();
    this.partitionPredictor = new PartitionPredictor();
  }

  async calculateQuorum(analysisInput) {
    co