Distributed Builds and Scalability

Distributed Builds and Scalability

Introduction to Distributed Builds

Why Distributed Builds?

Distributed builds in Jenkins allow organizations to:

  • Scale build capacity
  • Parallelize workloads
  • Optimize resource utilization
  • Reduce build times
  • Handle diverse build environments

Architecture Overview

Jenkins Master
    |
    +-- Agent 1 (Linux)
    |     +-- Workspace A
    |     +-- Workspace B
    |
    +-- Agent 2 (Windows)
    |     +-- Workspace C
    |
    +-- Agent 3 (MacOS)
          +-- Workspace D

Agent Management

Setting Up Agents

// Agent Configuration in Pipeline
pipeline {
    agent {
        label 'linux-agent'
        customWorkspace '/var/jenkins/workspace/custom'
    }
    stages {
        stage('Build') {
            steps {
                sh 'mvn clean install'
            }
        }
    }
}

Agent Types

1. SSH Agents

// SSH Agent Configuration
node('ssh-agent') {
    withCredentials([sshUserPrivateKey(
        credentialsId: 'ssh-agent-key',
        keyFileVariable: 'SSH_KEY'
    )]) {
        sh '''
            ssh -i $SSH_KEY user@agent-host \
            "cd /build && ./build.sh"
        '''
    }
}

2. JNLP Agents

<!-- JNLP Agent Configuration -->
<launcher class="hudson.slaves.JNLPLauncher">
    <workDirSettings>
        <disabled>false</disabled>
        <internalDir>remoting</internalDir>
        <failIfWorkDirIsMissing>false</failIfWorkDirIsMissing>
    </workDirSettings>
</launcher>

3. Docker Agents

// Docker Agent Pipeline
pipeline {
    agent {
        docker {
            image 'maven:3.8.4-openjdk-11'
            args '-v $HOME/.m2:/root/.m2'
        }
    }
    stages {
        stage('Build') {
            steps {
                sh 'mvn -B clean package'
            }
        }
    }
}

Scalability Patterns

Dynamic Provisioning

// AWS EC2 Dynamic Agent Configuration
cloud {
    name 'aws-ec2'
    instanceCapStr '10'
    
    templates {
        ec2Template {
            ami 'ami-12345678'
            instanceType 't2.medium'
            securityGroups 'jenkins-agent'
            remoteFS '/home/ec2-user'
            labels 'aws linux docker'
        }
    }
}

Load Balancing

// Load Balancing Configuration
pipeline {
    agent none
    stages {
        stage('Parallel Builds') {
            parallel {
                stage('Build 1') {
                    agent { label 'high-cpu' }
                    steps {
                        sh './build.sh'
                    }
                }
                stage('Build 2') {
                    agent { label 'high-memory' }
                    steps {
                        sh './test.sh'
                    }
                }
            }
        }
    }
}

Resource Management

Workspace Management

// Workspace Cleanup
properties([
    buildDiscarder(logRotator(
        numToKeepStr: '10',
        artifactNumToKeepStr: '5'
    )),
    disableConcurrentBuilds()
])

pipeline {
    agent any
    options {
        skipDefaultCheckout()
        timestamps()
        timeout(time: 1, unit: 'HOURS')
    }
    stages {
        stage('Cleanup') {
            steps {
                cleanWs()
            }
        }
    }
}

Resource Allocation

// Resource Pool Configuration
node('high-memory') {
    lock('database') {
        timeout(time: 1, unit: 'HOURS') {
            withEnv(['JAVA_OPTS=-Xmx4g']) {
                sh './run-tests.sh'
            }
        }
    }
}

High Availability

Master High Availability

# Jenkins HA Configuration
jenkins.ha.provider=aws-ha
jenkins.ha.cluster.name=jenkins-prod
jenkins.ha.instance.id=${INSTANCE_ID}
jenkins.ha.discovery.ec2.tags=Name=jenkins-ha

Backup Strategies

// Backup Configuration
node('backup-agent') {
    stage('Backup Jenkins') {
        steps {
            sh '''
                BACKUP_DIR=/backup/jenkins
                DATE=$(date +%Y%m%d)
                
                # Stop Jenkins
                systemctl stop jenkins
                
                # Backup JENKINS_HOME
                tar -czf $BACKUP_DIR/jenkins_$DATE.tar.gz \
                    /var/lib/jenkins
                
                # Start Jenkins
                systemctl start jenkins
                
                # Cleanup old backups
                find $BACKUP_DIR -type f -mtime +30 -delete
            '''
        }
    }
}

Performance Optimization

Build Optimization

// Build Cache Configuration
pipeline {
    agent any
    options {
        buildDiscarder(logRotator(
            numToKeepStr: '10'
        ))
        skipDefaultCheckout(true)
    }
    stages {
        stage('Fetch Dependencies') {
            steps {
                cache(maxCacheSize: 250, caches: [
                    [$class: 'ArbitraryFileCache',
                     includes: '**/*.jar',
                     path: '${HOME}/.m2/repository']
                ]) {
                    sh 'mvn dependency:go-offline'
                }
            }
        }
    }
}

Network Optimization

# Nginx Caching Configuration
proxy_cache_path /var/cache/nginx levels=1:2 keys_zone=jenkins_cache:10m;

server {
    location / {
        proxy_cache jenkins_cache;
        proxy_cache_use_stale error timeout http_500 http_502 http_503 http_504;
        proxy_cache_valid 200 60m;
    }
}

Monitoring and Maintenance

Health Checks

// Health Check Implementation
class JenkinsHealthCheck extends HealthCheck {
    @Override
    Result check() {
        try {
            // Check system metrics
            def memory = Runtime.runtime.maxMemory()
            def disk = new File("/").usableSpace
            
            if (memory < 1024 * 1024 * 1024) { // 1GB
                return Result.unhealthy("Low memory")
            }
            
            if (disk < 10 * 1024 * 1024 * 1024) { // 10GB
                return Result.unhealthy("Low disk space")
            }
            
            return Result.healthy()
        } catch (Exception e) {
            return Result.unhealthy(e)
        }
    }
}

Metrics Collection

// Metrics Configuration
metrics {
    name 'jenkins.builds'
    help 'Jenkins build metrics'
    labelNames 'job', 'result'
    
    counter {
        name 'total_builds'
        help 'Total number of builds'
    }
    
    gauge {
        name 'build_duration'
        help 'Build duration in seconds'
    }
}

Hands-on Exercises

Exercise 1: Agent Setup

  1. Configure SSH Agent
  2. Set up JNLP Agent
  3. Implement Docker Agent
  4. Test Connectivity
  5. Monitor Performance

Exercise 2: Scalability Implementation

  1. Configure Dynamic Provisioning
  2. Implement Load Balancing
  3. Set up Resource Management
  4. Configure High Availability
  5. Test Scaling Scenarios

Assessment

Knowledge Check

  1. What are the benefits of distributed builds?
  2. How do you configure different agent types?
  3. What are the key considerations for scalability?
  4. How do you implement high availability?

Practice Tasks

  1. Set up multiple agent types
  2. Implement dynamic provisioning
  3. Configure resource management
  4. Set up monitoring

Additional Resources

Documentation

Best Practices

  • Regular maintenance
  • Resource monitoring
  • Backup strategy
  • Performance optimization

Next Steps

  • Review distributed concepts
  • Practice agent management
  • Implement scaling strategies
  • Study monitoring patterns
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Jenkins Architecture Patterns
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Dynamic Agent Provisioning