Architecture Documentation - Jenkins as Code

Comprehensive architecture guide for Jenkins as Code automation framework

Updated Jan 15, 2024

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Architecture Documentation

Comprehensive architecture guide for Jenkins as Code automation framework

📋 Table of Contents

• System Overview
• Architecture Layers
• Component Details
• Data Flow
• Security Architecture
• Scalability & Performance
• Disaster Recovery

🎯 System Overview

High-Level Architecture

┌─────────────────────────────────────────────────────────────────┐
│                    Infrastructure Layer (Ansible)                 │
│  ┌──────────────┐  ┌──────────────┐  ┌──────────────┐          │
│  │   Packer     │  │  Monitoring  │  │   Jenkins     │          │
│  │   Playbook   │  │   Stack     │  │   Stack      │          │
│  └──────────────┘  └──────────────┘  └──────────────┘          │
└─────────────────────────────────────────────────────────────────┘
                            │
                            ▼
┌─────────────────────────────────────────────────────────────────┐
│              Configuration Layer (CaC)                            │
│  ┌──────────────┐  ┌──────────────┐  ┌──────────────┐          │
│  │ jenkins.yaml │  │  seed-jobs    │  │  init.groovy  │          │
│  │   (CaC)      │  │  (JobDSL)    │  │  (Plugins)    │          │
│  └──────────────┘  └──────────────┘  └──────────────┘          │
└─────────────────────────────────────────────────────────────────┘
                            │
                            ▼
┌─────────────────────────────────────────────────────────────────┐
│              Job Generation Layer (JobGenie)                      │
│  ┌──────────────┐  ┌──────────────┐  ┌──────────────┐          │
│  │  JobGenie    │  │  Shared      │  │   Pipeline   │          │
│  │  Scripts     │  │  Libraries   │  │   Templates  │          │
│  └──────────────┘  └──────────────┘  └──────────────┘          │
└─────────────────────────────────────────────────────────────────┘
                            │
                            ▼
┌─────────────────────────────────────────────────────────────────┐
│              Execution Layer (Jenkins Jobs)                       │
│  ┌──────────────┐  ┌──────────────┐  ┌──────────────┐          │
│  │   Build      │  │   Deploy     │  │   Manage     │          │
│  │   Jobs       │  │   Jobs       │  │   Jobs       │          │
│  └──────────────┘  └──────────────┘  └──────────────┘          │
└─────────────────────────────────────────────────────────────────┘

🏗️ Architecture Layers

Layer 1: Infrastructure Layer

Purpose: Provision and configure Jenkins infrastructure

Components:

• Ansible Playbooks: Infrastructure automation
• Packer Templates: AMI/image building
• Monitoring Stack: Telegraf, Filebeat, ELK

Key Files:

mCloud-infra/ansible/
├── packer.yml                    # Main playbook
├── roles/
│   ├── monitoring/               # Monitoring stack
│   └── users/                    # User management
└── group_vars/
    └── packer_al2023_aarch64_devops_jenkins.yml

Responsibilities:

• Server provisioning
• Jenkins installation
• Plugin management
• System configuration
• Monitoring setup

Layer 2: Configuration Layer

Purpose: Manage Jenkins configuration as code

Components:

• Jenkins Configuration as Code (CaC): YAML-based config
• JobDSL Seed Jobs: Initial job generation
• Init Scripts: Plugin installation

Key Files:

mCloud-infra/ansible/roles/monitoring/templates/stacks/jenkins/
├── jenkins.yaml.j2               # Main CaC template
├── seed-jobs.groovy.j2           # Seed job DSL
└── init.groovy.j2                 # Plugin initialization

Configuration Sources:

1. Ansible Variables → Jinja2 Templates → YAML Files → Jenkins CaC

Responsibilities:

• Jenkins system configuration
• Security settings
• Global libraries
• Credential management
• View configuration

Layer 3: Job Generation Layer

Purpose: Dynamically generate Jenkins jobs

Components:

• JobGenie Scripts: Job definition files
• Shared Libraries: Reusable pipeline utilities
• Pipeline Templates: Standardized CI/CD patterns

Key Files:

mCloud-Jenkins/
├── amazon/
│   └── mcloud/
│       └── nonprod/
│           └── pipelines/
│               └── jobs/
│                   └── JobGenie.groovy
└── sharedlibs/
    ├── src/org/devops/
    │   └── CommonUtils.groovy
    └── vars/
        ├── pipelineUtils.groovy
        └── sendNotifications.groovy

Job Generation Flow:

JobGenie.groovy → Seed Job → JobDSL → Jenkins Jobs

Responsibilities:

• Job definition parsing
• Job generation logic
• Folder structure creation
• Parameter configuration
• Pipeline linking

Layer 4: Execution Layer

Purpose: Execute CI/CD pipelines

Components:

• Generated Jenkins Jobs: Build, deploy, manage jobs
• Pipeline Templates: Reusable Jenkinsfiles
• External Integrations: ArgoCD, ECR, Slack

Job Types:

1. Build Jobs: Docker image building
2. Deploy Jobs: Kubernetes deployments
3. Manage Jobs: Infrastructure management

🔧 Component Details

1. Ansible Automation

Playbook Structure

# packer.yml
- hosts: packer_al2023_aarch64_devops_jenkins
  roles:
    - monitoring
  tasks:
    - name: Install Jenkins
    - name: Configure Jenkins
    - name: Install plugins

Role Organization

roles/
├── monitoring/
│   ├── tasks/
│   │   ├── install/
│   │   └── main.yml
│   ├── templates/
│   │   └── stacks/jenkins/
│   └── defaults/
│       └── main.yml

2. Jenkins Configuration as Code

Configuration Structure

jenkins:
  numExecutors: 2
  authorizationStrategy:
    roleBased:
      roles:
        global:
          - name: "admin"
            permissions: ["Overall/Administer"]
  views:
    - all:
        name: "all"

Template Generation

# jenkins.yaml.j2
jenkins:
  numExecutors: {{ jenkins_num_executors | default(2) }}
  authorizationStrategy:
    roleBased:
      roles:
        global:
          - name: "admin"
            entries: {{ overall_admin_users | to_json }}

3. JobGenie Engine

Job Definition Format

def jobGenie = [
    "mcloud": [
        [
            APP_REPO: 'my-app',
            APP_BRANCH: 'master',
            appNames: ['my-service'],
            DOCKER_BUILD_ARGS: 'ENV'
        ]
    ]
]

Generation Process

// CommonUtils.mCloudJobsGenerator()
jobGenie.each { techteam, values ->
    values.each { config ->
        // Merge configurations
        def pConfig = defaultConfigs + config
        
        // Create folders
        createFolders(dsl, ...)
        
        // Generate jobs
        pConfig.appNames.each { appName ->
            pipelineGenerator(dsl, deploy, buildVars, jobParams)
        }
    }
}

4. Shared Libraries

CommonUtils Class

class CommonUtils {
    static void createFolders(DslFactory dsl, List<Map> configs)
    static void pipelineGenerator(DslFactory dsl, Map deploy, ...)
    static void mCloudJobsGenerator(DslFactory dsl, Map jobGenie, ...)
}

Pipeline Utilities

// vars/pipelineUtils.groovy
def generateDockerArgs(Map opts = [:])
def updateCanarySteps(int steps, String file)
def sendJobNotification(String status, String message = '')

🔄 Data Flow

Configuration Flow

┌─────────────┐
│   Developer │
└──────┬──────┘
       │ 1. Edit JobGenie.groovy
       ▼
┌─────────────┐
│  Git Repo   │
└──────┬──────┘
       │ 2. Commit & Push
       ▼
┌─────────────┐
│  Seed Job   │
└──────┬──────┘
       │ 3. Read JobGenie
       ▼
┌─────────────┐
│  JobDSL     │
└──────┬──────┘
       │ 4. Generate Jobs
       ▼
┌─────────────┐
│  Jenkins    │
└─────────────┘

Deployment Flow

┌─────────────┐
│  Build Job  │
└──────┬──────┘
       │ 1. Build Docker Image
       ▼
┌─────────────┐
│     ECR     │
└──────┬──────┘
       │ 2. Push Image
       ▼
┌─────────────┐
│  Deploy Job │
└──────┬──────┘
       │ 3. Update Config
       ▼
┌─────────────┐
│   ArgoCD    │
└──────┬──────┘
       │ 4. Deploy to K8s
       ▼
┌─────────────┐
│   EKS       │
└─────────────┘

🔐 Security Architecture

Authentication & Authorization

Security Realm

jenkins:
  securityRealm:
    local:
      allowsSignup: false
      users:
        - id: "admin"
          password: "Admin@123"

Role-Based Access Control

authorizationStrategy:
  roleBased:
    roles:
      items:
        - name: "amazon-mcloud-dev"
          pattern: "amazon/mcloud/.*/nonprod/deploy/.*"
          templateName: "build"
          entries:
            - user: "dev"

Credential Management

Credential Storage

• Jenkins Credentials Plugin
• AWS Secrets Manager integration
• Encrypted at rest

SSH Key Management

SSH_KEYS: 'default:/var/lib/jenkins/.ssh/id_rsa'

Network Security

• HTTPS only
• Firewall rules
• Network policies
• VPN access for sensitive operations

📈 Scalability & Performance

Horizontal Scaling

Jenkins Agents

jenkins_slave_nodes:
  linux-slave:
    host: "10.20.0.2"
    numExecutors: 4

Load Distribution

• Multiple Jenkins agents
• Job distribution
• Resource optimization

Performance Optimization

Caching

• Docker layer caching
• Maven/Gradle caching
• Git repository caching

Resource Management

• Build timeouts
• Concurrent build limits
• Resource quotas

🛡️ Disaster Recovery

Backup Strategy

Configuration Backup

• Git repository (source of truth)
• Jenkins configuration export
• Regular backups

Data Backup

jenkins_s3_backup_dir: "s3://mys3-bucket/amazon/mcloud/backup/jenkins"

Recovery Procedures

Full Recovery

1. Provision new server
2. Run Ansible playbook
3. Restore from Git
4. Verify configuration

Partial Recovery

1. Restore specific jobs
2. Re-run seed jobs
3. Verify functionality

RTO/RPO Targets

• RTO: < 30 minutes
• RPO: < 1 hour

📊 Monitoring & Observability

Metrics Collection

System Metrics

• CPU, Memory, Disk
• Network I/O
• Jenkins performance

Application Metrics

• Build success rate
• Deployment frequency
• Mean time to recovery

Logging

Log Aggregation

• Filebeat → ELK Stack
• Centralized logging
• Log retention policies

Audit Trail

audit-trail:
  logBuildCause: true
  logCredentialsUsage: true
  logFile: "/var/log/jenkins/audit-trail.log"

🔄 Continuous Improvement

Version Control

• All configurations in Git
• Semantic versioning
• Change tracking

Testing

• Ansible playbook testing
• JobDSL validation
• Integration testing

Documentation

• Architecture documentation
• Runbooks
• Troubleshooting guides

📚 Additional Resources

📖 Related Documentation

• 🏠 Main Documentation - Complete Jenkins as Code framework overview
• ⚙️ JobGenie Guide - JobGenie usage and examples
• 🚀 DevOps as a Service - Self-service CI/CD platform guide
• ✅ Best Practices - Recommended practices and guidelines
• 🔧 Setup Guide - Setup and configuration guide
• 📝 Quick Reference - Quick reference guide

🧭 Navigation

Related Topics:

• Learn JobGenie to understand job generation
• Review Best Practices for architecture decisions
• See DevOps as a Service for implementation patterns

---

Maintained by the DevOps Team

---

Last Updated: January 15, 2024
Version: 1.0.0

Tags: #Jenkins #Architecture #Infrastructure as Code #Configuration as Code #Ansible #JobDSL

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