Jenkins Installation & Configuration

Installing Jenkins with Docker

The fastest way to get Jenkins running:

# Create a Docker network
docker network create jenkins
 
# Run Jenkins
docker run -d \
  --name jenkins \
  --network jenkins \
  -p 8080:8080 \
  -p 50000:50000 \
  -v jenkins_home:/var/jenkins_home \
  -v /var/run/docker.sock:/var/run/docker.sock \
  jenkins/jenkins:lts
 
# Get the initial admin password
docker exec jenkins cat /var/jenkins_home/secrets/initialAdminPassword

Installing on Ubuntu/Debian

# Add Jenkins repository key
curl -fsSL https://pkg.jenkins.io/debian-stable/jenkins.io-2023.key | \
  sudo tee /usr/share/keyrings/jenkins-keyring.asc > /dev/null
 
# Add repository
echo "deb [signed-by=/usr/share/keyrings/jenkins-keyring.asc] \
  https://pkg.jenkins.io/debian-stable binary/" | \
  sudo tee /etc/apt/sources.list.d/jenkins.list > /dev/null
 
# Install Java and Jenkins
sudo apt update
sudo apt install fontconfig openjdk-17-jre jenkins -y
 
# Start Jenkins
sudo systemctl start jenkins
sudo systemctl enable jenkins
 
# Get initial password
sudo cat /var/lib/jenkins/secrets/initialAdminPassword

Initial Setup

Open http://localhost:8080 in your browser
Enter the initial admin password
Choose "Install suggested plugins" (recommended)
Create your admin user
Configure the Jenkins URL

Essential Plugins

Plugin	Purpose
Pipeline	Pipeline as Code support
Git	Git SCM integration
Docker Pipeline	Build with Docker agents
Blue Ocean	Modern UI for pipelines
Credentials Binding	Secure credential management
SSH Agent	SSH key management
Workspace Cleanup	Clean workspace between builds
Timestamper	Add timestamps to console output

# Install plugins via CLI
jenkins-cli install-plugin pipeline-stage-view docker-workflow blueocean

Managing Credentials

Jenkins stores credentials securely for use in pipelines.

Adding Credentials

Navigate to: Manage Jenkins → Credentials → System → Global credentials

Credential Types

Type	Use Case
Username/Password	Git repos, Docker registries
SSH Key	Server access, Git over SSH
Secret Text	API tokens, passwords
Secret File	Certificates, config files
Certificate	PKCS#12 certificates

Using Credentials in Pipelines

pipeline {
    agent any
 
    environment {
        DOCKER_CREDS = credentials('docker-hub-creds')
        AWS_ACCESS_KEY = credentials('aws-access-key')
    }
 
    stages {
        stage('Login') {
            steps {
                sh 'echo $DOCKER_CREDS_PSW | docker login -u $DOCKER_CREDS_USR --password-stdin'
            }
        }
    }
}

Configuring Jenkins

Global Tool Configuration

Navigate to: Manage Jenkins → Tools

Configure:

JDK — Java installations
Git — Git executable path
NodeJS — Node.js versions
Docker — Docker installations

System Configuration

Navigate to: Manage Jenkins → System

Key settings:

Jenkins URL
System Admin email
SMTP for notifications
GitHub/GitLab server connections

Setting Up Agents

SSH Agent

# On the agent machine
sudo apt install openjdk-17-jre -y
sudo useradd -m -s /bin/bash jenkins
sudo mkdir -p /home/jenkins/.ssh
 
# Copy the master's public key to the agent
# Then in Jenkins UI: Manage Jenkins → Nodes → New Node

Docker Agent

pipeline {
    agent {
        docker {
            image 'node:20-alpine'
            args '-v /tmp:/tmp'
        }
    }
    stages {
        stage('Build') {
            steps {
                sh 'node --version'
                sh 'npm install'
                sh 'npm run build'
            }
        }
    }
}

Jenkins Security

Best Practices

Enable CSRF protection (enabled by default)
Use Role-Based Access Control (RBAC)
Never run Jenkins as root
Keep Jenkins and plugins updated
Use credentials store for all secrets
Enable audit logging

// Jenkinsfile security — never hardcode secrets
// BAD:
// sh 'curl -H "Authorization: Bearer abc123" ...'
 
// GOOD:
withCredentials([string(credentialsId: 'api-token', variable: 'TOKEN')]) {
    sh 'curl -H "Authorization: Bearer $TOKEN" ...'
}

Summary

You've learned:

How to install Jenkins via Docker and native packages
Initial setup and plugin management
Credential management for secure pipelines
Configuring tools, agents, and system settings
Security best practices

Next Steps

Next, we'll write Jenkinsfiles and build real CI/CD pipelines.

Learning Objectives