GitLab Infrastructure

The GitLab infrastructure is a complex system that consists of many different components, including web servers, application servers, databases, and load balancers. This document provides an overview of the GitLab infrastructure and its components.

Web Servers

GitLab uses Nginx as its primary web server. Nginx is a high-performance web server that is known for its efficiency and scalability. It is responsible for handling HTTP requests from clients and routing them to the appropriate backend services.

Configuration:

The Nginx configuration file is located at /etc/nginx/nginx.conf.

Example Configuration:

server {
              listen 80;
              server_name gitlab.com;
          
              location / {
                  proxy_pass http://gitlab-app:80;
              }
          }
          

Reference:

• Nginx Documentation

Application Servers

GitLab runs on a Ruby on Rails application server. The application server is responsible for handling requests from the web server and processing them.

Configuration:

The GitLab application server is configured through the gitlab.rb file. This file contains all the settings for the GitLab application.

Example Configuration:

gitlab_rails['gitlab_shell_ssh_port'] = 22
          gitlab_rails['smtp_enable'] = true
          gitlab_rails['smtp_address'] = "smtp.example.com"
          gitlab_rails['smtp_port'] = 587
          gitlab_rails['smtp_user_name'] = "[email protected]"
          gitlab_rails['smtp_password'] = "password"
          

Reference:

• GitLab Configuration File

Databases

GitLab uses PostgreSQL as its primary database. PostgreSQL is a powerful and reliable database that is well-suited for handling large datasets. It stores all of the data for the GitLab application, including user information, repositories, and project data.

Configuration:

The PostgreSQL database is configured through the postgresql.conf file. This file contains all the settings for the PostgreSQL database.

Example Configuration:

listen_addresses = '*'
          port = 5432
          max_connections = 100
          shared_buffers = 128MB
          

Reference:

• PostgreSQL Documentation

Load Balancers

GitLab uses a load balancer to distribute traffic across multiple application servers. This helps to ensure that the application is always available and that requests are handled efficiently.

Configuration:

The load balancer configuration depends on the specific load balancer used.

Example Configuration:

# HAProxy Configuration
          global
              log 127.0.0.1 local0
              log 127.0.0.1 local1 notice
              chroot /var/lib/haproxy
              stats socket /run/haproxy/admin.sock mode 660 level admin expose-fd listeners
              user haproxy
              group haproxy
              daemon
          
          defaults
              log global
              mode http
              option httplog
              option dontlognull
              timeout connect 5000
              timeout client 50000
              timeout server 50000
          

Reference:

• HAProxy Documentation

Monitoring and Logging

GitLab uses a variety of tools for monitoring and logging its infrastructure. These tools provide insight into the performance and health of the system.

Monitoring:

GitLab uses Prometheus for monitoring its infrastructure. Prometheus is an open-source monitoring system that collects metrics from various sources and provides real-time dashboards for monitoring.

Logging:

GitLab uses Graylog for centralized logging. Graylog is an open-source logging platform that collects logs from various sources and provides a central interface for searching and analyzing logs.

References:

• Prometheus Documentation
• Graylog Documentation

Continuous Integration and Continuous Delivery (CI/CD)

GitLab uses GitLab CI/CD to automate the build, test, and deployment of its software. GitLab CI/CD is a powerful and flexible platform that enables developers to automate their workflows.

Configuration:

GitLab CI/CD is configured through a .gitlab-ci.yml file. This file specifies the steps involved in the build, test, and deployment process.

Example Configuration:

stages:
            - build
            - test
            - deploy
          
          build:
            stage: build
            script:
              - echo "Building the application..."
              - make build
          
          test:
            stage: test
            script:
              - echo "Testing the application..."
              - make test
          
          deploy:
            stage: deploy
            script:
              - echo "Deploying the application..."
              - make deploy
          

Reference:

• GitLab CI/CD Documentation

This outline provides a high-level overview of the GitLab infrastructure. For more detailed information, please refer to the documentation links provided.