# GitLab

## Overview

GitLab is an end-to-end DevOps platform that combines source control management, CI/CD, security scanning, package registry, and more in a single application. As of 2025, GitLab has evolved into a comprehensive DevSecOps lifecycle tool with advanced AI capabilities and improved scalability.

## Key Features

* **Source Control Management**: Git repository management with advanced branch protection and merge request workflows
* **CI/CD Pipelines**: Built-in continuous integration and deployment with auto-scaling runners
* **Container Registry**: Private container registry with vulnerability scanning
* **Security Scanning**: SAST, DAST, dependency scanning, and container scanning
* **Issue Tracking**: Agile project management with epics, issues, and milestones
* **Wiki & Documentation**: Built-in documentation system with markdown support
* **Value Stream Analytics**: Metrics and insights for the entire DevOps lifecycle
* **Infrastructure as Code**: Terraform integration and infrastructure management
* **AI-Powered Features**: Automated code review, security scanning, and merge request analysis

## Real-Life Scenarios

### Enterprise Migration Case Study

**Company**: Global Financial Services Provider**Challenge**: Migrate from multiple disparate tools to a unified DevOps platform**Solution**: GitLab Premium self-hosted deployment

**Implementation Steps**:

1. Set up high-availability GitLab installation across multiple data centers
2. Migrated 5000+ repositories from various sources (GitHub, Bitbucket, SVN)
3. Implemented custom CI/CD templates for standardization
4. Integrated with existing LDAP and SSO systems

**Results**:

* 40% reduction in tool maintenance costs
* 60% faster deployment cycles
* Improved security compliance with built-in scanning
* Standardized DevOps practices across 200+ teams

### Startup Scale-Up Scenario

**Company**: AI/ML Platform Provider**Challenge**: Need for rapid scaling with limited DevOps resources**Solution**: GitLab Ultimate Cloud (SaaS)

**Implementation**:

1. Utilized Auto DevOps for automatic CI/CD configuration
2. Implemented container scanning and dependency tracking
3. Set up review apps for feature branch testing
4. Integrated with cloud Kubernetes clusters

**Results**:

* Zero-touch deployment pipeline for 100+ microservices
* 90% reduction in security vulnerabilities
* Automated compliance reporting
* 3x faster onboarding for new developers

## Installation Guide

### Linux Installation (Ubuntu/Debian)

```bash
# Add GitLab repository
curl -s https://packages.gitlab.com/install/repositories/gitlab/gitlab-ee/script.deb.sh | sudo bash

# Install GitLab
sudo EXTERNAL_URL="https://gitlab.example.com" apt-get install gitlab-ee

# Configure and start GitLab
sudo gitlab-ctl reconfigure
```

### Windows Subsystem for Linux (WSL)

```bash
# Update WSL system
sudo apt update && sudo apt upgrade -y

# Install prerequisites
sudo apt install -y curl openssh-server ca-certificates tzdata perl

# Add GitLab repository
curl -s https://packages.gitlab.com/install/repositories/gitlab/gitlab-ee/script.deb.sh | sudo bash

# Install GitLab
sudo EXTERNAL_URL="http://localhost" apt-get install gitlab-ee

# Configure and start GitLab
sudo gitlab-ctl reconfigure
```

### NixOS Installation

```nix
# In configuration.nix
{ config, pkgs, ... }:

{
  services.gitlab = {
    enable = true;
    port = 80;
    host = "gitlab.example.com";
    https = true;
    initialRootPassword = "file:/var/keys/gitlab/root_password";
    
    # Configure backup
    backup = {
      enable = true;
      path = "/var/backup/gitlab";
      interval = "daily";
    };
    
    # Configure SMTP
    smtp = {
      enable = true;
      address = "smtp.example.com";
      port = 587;
    };
    
    # Extra configuration
    extraConfig = {
      gitlab = {
        email_from = "gitlab@example.com";
        email_display_name = "GitLab";
      };
    };
  };

  # Open firewall ports
  networking.firewall.allowedTCPPorts = [ 80 443 ];
}
```

## Pros and Cons

### Advantages

1. **Complete DevOps Platform**
   * Single application for entire DevOps lifecycle
   * Reduced tool integration complexity
   * Unified authentication and authorization
2. **Self-Hosted Option**
   * Complete control over data and infrastructure
   * Customizable to specific requirements
   * Air-gapped installation support
3. **Built-in CI/CD**
   * No third-party CI/CD tools needed
   * Native container registry integration
   * Auto DevOps capability
4. **Security Features**
   * Comprehensive security scanning
   * Container vulnerability analysis
   * Compliance management
5. **Value Stream Analytics**
   * End-to-end DevOps metrics
   * Team productivity insights
   * Release analytics

### Disadvantages

1. **Resource Requirements**
   * Higher system requirements for self-hosted
   * Significant maintenance overhead
   * Complex HA setup
2. **Learning Curve**
   * Complex configuration options
   * Extensive feature set to master
   * Regular updates to keep up with
3. **Cost**
   * Higher pricing for premium features
   * Self-hosted infrastructure costs
   * Storage costs for large repos

## Comparison with Alternatives

### GitLab vs GitHub

| Feature            | GitLab        | GitHub           |
| ------------------ | ------------- | ---------------- |
| Source Control     | Native Git    | Native Git       |
| CI/CD              | Built-in      | GitHub Actions   |
| Container Registry | Included      | Included         |
| Issue Tracking     | Comprehensive | Basic            |
| Wiki               | Built-in      | Built-in         |
| Self-Hosted        | Yes           | Yes (Enterprise) |
| Free Tier          | More features | Limited features |
| Community          | Smaller       | Larger           |
| Package Registry   | Comprehensive | Basic            |
| Security Scanning  | Built-in      | Marketplace apps |

### GitLab vs Azure DevOps

| Feature            | GitLab       | Azure DevOps         |
| ------------------ | ------------ | -------------------- |
| Source Control     | Native Git   | Git/TFVC             |
| CI/CD              | Built-in     | Azure Pipelines      |
| Artifact Storage   | Built-in     | Azure Artifacts      |
| Work Items         | Issues/Epics | Rich work item types |
| Test Management    | Basic        | Comprehensive        |
| Cloud Integration  | Multi-cloud  | Azure-focused        |
| Scaling            | Manual/Auto  | Auto-scaling         |
| Cost Model         | User-based   | User/Parallel job    |
| Release Management | Built-in     | Comprehensive        |
| Security           | Built-in     | Azure Security       |

## Best Practices

1. **Repository Management**
   * Use merge request templates
   * Implement branch protection rules
   * Regular repository maintenance
2. **CI/CD Configuration**
   * Use include templates
   * Implement caching strategies
   * Optimize pipeline performance
3. **Security**
   * Enable all security scanners
   * Regular security policy updates
   * Implement role-based access
4. **Performance**
   * Regular instance tuning
   * Implement Geo replication
   * Monitor system resources
5. **Backup and Recovery**
   * Regular backup testing
   * Implement HA where needed
   * Document recovery procedures

## Related Topics

* [Git Workflows](https://github.com/olafkfreund/wiki/blob/main/pages/devops/source-control/git-workflows.md)
* [CI/CD Pipelines](https://github.com/olafkfreund/wiki/blob/main/pages/devops/ci-cd/README.md)
* [Container Registry](https://github.com/olafkfreund/wiki/blob/main/pages/devops/containers/README.md)
* [Security Scanning](../security-and-compliance/security/security)
* [Infrastructure as Code](https://github.com/olafkfreund/wiki/blob/main/pages/devops/iac/README.md)
