Distributed Builds and Scalability

Distributed Builds and Scalability

Introduction to Distributed Builds

Why Distributed Builds?

  • Improved performance
  • Resource optimization
  • Parallel execution
  • Load balancing
  • High availability

Architecture Overview

  • Master-agent model
  • Communication protocols
  • Resource allocation
  • Job distribution
  • Build coordination

Agent Configuration

Static Agents

// Static Agent Configuration
jenkins:
  nodes:
    - permanent:
        name: "build-agent-1"
        remoteFS: "/home/jenkins"
        launcher:
          ssh:
            host: "agent1.example.com"
            credentialsId: "agent-ssh-key"
            port: 22
            jvmOptions: "-Xmx2g"

Dynamic Agents

// Kubernetes Dynamic Agent
pipeline {
    agent {
        kubernetes {
            yaml '''
                apiVersion: v1
                kind: Pod
                spec:
                  containers:
                  - name: maven
                    image: maven:3.8.4-openjdk-11
                    command:
                    - cat
                    tty: true
                    resources:
                      requests:
                        memory: "2Gi"
                        cpu: "1"
                      limits:
                        memory: "4Gi"
                        cpu: "2"
            '''
        }
    }
    stages {
        stage('Build') {
            steps {
                container('maven') {
                    sh 'mvn clean package'
                }
            }
        }
    }
}

Load Balancing

Load Distribution Strategies

// Load Balancer Configuration
jenkins:
  clouds:
    kubernetes:
      templates:
        - name: "dynamic-agent"
          label: "build-pod"
          idleMinutes: 10
          containers:
            - name: "jnlp"
              image: "jenkins/inbound-agent:4.11.2-4"
              resources:
                requests:
                  cpu: "500m"
                  memory: "1Gi"
          nodeSelector:
            node-role: "builder"

Resource Allocation

// Resource-based Job Assignment
pipeline {
    agent {
        label 'high-cpu || high-memory'
    }
    options {
        throttle(['heavy-jobs'])
    }
    stages {
        stage('Resource-Intensive Build') {
            steps {
                sh '''
                    # Resource-intensive operation
                    make -j8 all
                '''
            }
        }
    }
}

High Availability

Master Redundancy

# High Availability Configuration
apiVersion: v1
kind: StatefulSet
metadata:
  name: jenkins-ha
spec:
  replicas: 2
  selector:
    matchLabels:
      app: jenkins-ha
  template:
    metadata:
      labels:
        app: jenkins-ha
    spec:
      containers:
      - name: jenkins
        image: jenkins/jenkins:lts
        ports:
        - containerPort: 8080
        volumeMounts:
        - name: jenkins-home
          mountPath: /var/jenkins_home
  volumeClaimTemplates:
  - metadata:
      name: jenkins-home
    spec:
      accessModes: ["ReadWriteOnce"]
      resources:
        requests:
          storage: 50Gi

Failover Configuration

// Failover Pipeline Configuration
properties([
    durabilityHint('PERFORMANCE_OPTIMIZED'),
    disableConcurrentBuilds(),
    buildDiscarder(logRotator(numToKeepStr: '10'))
])

pipeline {
    agent any
    options {
        timeout(time: 1, unit: 'HOURS')
        retry(3)
    }
    stages {
        stage('Build with Failover') {
            steps {
                catchError(buildResult: 'SUCCESS', stageResult: 'FAILURE') {
                    script {
                        def agents = Jenkins.instance.nodes.collect { it.nodeName }
                        def currentAgent = env.NODE_NAME
                        
                        if (!agents.contains(currentAgent)) {
                            error "Agent ${currentAgent} not available"
                        }
                    }
                }
            }
        }
    }
}

Performance Optimization

Build Caching

// Build Cache Configuration
pipeline {
    agent any
    options {
        skipDefaultCheckout()
    }
    stages {
        stage('Checkout with Cache') {
            steps {
                cache(maxCacheSize: 250, caches: [
                    [$class: 'ArbitraryFileCache',
                     includes: '**/*.jar',
                     path: '.m2/repository']
                ]) {
                    git url: 'https://github.com/example/project.git'
                    sh 'mvn clean package'
                }
            }
        }
    }
}

Parallel Execution

// Parallel Build Pipeline
pipeline {
    agent none
    stages {
        stage('Parallel Builds') {
            parallel {
                stage('Unit Tests') {
                    agent { label 'test-agent' }
                    steps {
                        sh 'mvn test'
                    }
                }
                stage('Integration Tests') {
                    agent { label 'integration-agent' }
                    steps {
                        sh 'mvn verify'
                    }
                }
                stage('Security Scan') {
                    agent { label 'security-agent' }
                    steps {
                        sh 'run-security-scan'
                    }
                }
            }
        }
    }
}

Monitoring and Management

Agent Health Checks

// Agent Health Check Pipeline
pipeline {
    agent none
    stages {
        stage('Agent Health Check') {
            steps {
                script {
                    def agents = Jenkins.instance.nodes
                    agents.each { agent ->
                        def computer = agent.computer
                        if (computer.offline) {
                            echo "Agent ${agent.nodeName} is offline"
                            try {
                                computer.connect(false)
                            } catch (Exception e) {
                                error "Failed to connect to ${agent.nodeName}: ${e.message}"
                            }
                        }
                    }
                }
            }
        }
    }
}

Resource Monitoring

// Resource Monitoring Pipeline
pipeline {
    agent any
    triggers { cron('H/15 * * * *') }
    stages {
        stage('Monitor Resources') {
            steps {
                script {
                    def metrics = [
                        activeExecutors: Jenkins.instance.computers.sum { it.executors.size() },
                        busyExecutors: Jenkins.instance.computers.sum { it.executors.count { ex -> ex.isBusy() } },
                        queueLength: Jenkins.instance.queue.items.length
                    ]
                    
                    echo "Resource Metrics:"
                    echo "Active Executors: ${metrics.activeExecutors}"
                    echo "Busy Executors: ${metrics.busyExecutors}"
                    echo "Queue Length: ${metrics.queueLength}"
                    
                    if (metrics.queueLength > 10) {
                        emailext (
                            subject: "Jenkins Queue Alert",
                            body: "High queue length detected: ${metrics.queueLength} items",
                            to: 'admin@example.com'
                        )
                    }
                }
            }
        }
    }
}

Best Practices

Scalability Checklist

  1. Proper agent sizing
  2. Resource allocation
  3. Load balancing
  4. Caching strategy
  5. Network optimization
  6. Monitoring setup
  7. Failover planning
  8. Performance tuning

Implementation Guide

  1. Configure master node
  2. Set up agents
  3. Implement load balancing
  4. Configure high availability
  5. Set up monitoring
  6. Optimize performance
  7. Regular maintenance

Hands-on Exercise

Exercise 1: Agent Setup

  1. Configure static agent
  2. Set up dynamic agents
  3. Implement load balancing
  4. Test agent connectivity
  5. Monitor performance

Exercise 2: High Availability

  1. Configure master redundancy
  2. Set up failover
  3. Implement monitoring
  4. Test failover scenarios
  5. Verify recovery

Assessment

Knowledge Check

  1. What are distributed build benefits?
  2. How do you configure agents?
  3. What are load balancing strategies?
  4. How do you implement high availability?

Practice Tasks

  1. Set up distributed builds
  2. Configure load balancing
  3. Implement high availability
  4. Monitor performance

Additional Resources

Documentation

Best Practices

  • Regular maintenance
  • Performance monitoring
  • Resource optimization
  • Capacity planning

Next Steps

  • Review distributed concepts
  • Practice implementation
  • Explore advanced features
  • Study real-world scenarios