Jenkins Master Docker - PART1

Jenkins master with docker and docker-compose

Jenkins is one of the most popular CI/CD tools which allow automating workflows and processes. In this post, we will describe how to deploy Jenkins in a local server using docker and docker-compose. Implementation Jenkins through docker allows:

• Jenkins configuration files live inside the container rather than the host machine.
• Docker instances are easier to manage and repeatable if you are interested in running Jenkins on multiple platforms.
• You can easily create and destroy the Jenkins server and persist Jenkins data through volumes so we don’t need to re-run the Jenkins setup.

By default, Jenkins comes with its own built-in Winstone web server listening on port 8080, which is convenient for getting started. But in production systems, Jenkins should be secured by setting SSL to protect passwords and sensitive data transmitted through the web.

Prerequisites:

• docker
• docker-compose

Architecture

Setting up Jenkins Master + Nginx Docker/Docker-compose

Project file structure

|-- docker-compose.yml # Jenkins Master + Nginx docker-compose file
`-- nginx
    |-- certs # Nginx private key and certificate
    |   |-- jenkins.crt
    |   `-- jenkins.key
    `-- conf.d
        `-- jenkins.conf # Nginx configuration file

Nginx configuration

Let’s start by creating an Nginx configuration as a reverse proxy to direct client requests to Jenkins:

# jenkins.conf
server {
  listen 80;
  server_name hostname.example.com;
  server_tokens off;
  return 301 https://$host:443$request_uri;
}

server {
  listen      443 ssl http2;    # Listen on port 443 for IPv4 requests

  server_name     hostname.example.com;

  ssl_certificate /etc/ssl/jenkins.crt;
  ssl_certificate_key /etc/ssl/jenkins.key;

  access_log      /var/log/nginx/jenkins/access.log;
  error_log       /var/log/nginx/jenkins/error.log;

  server_tokens off;

  location / {
    proxy_set_header        Host $host;
    proxy_set_header        X-Real-IP $remote_addr;
    proxy_set_header        X-Forwarded-For $proxy_add_x_forwarded_for;
    proxy_set_header        X-Forwarded-Proto $scheme;

    proxy_pass          http://jenkins_master:8080;
    proxy_read_timeout  90;
    # Fix the “It appears that your reverse proxy set up is broken" error.
    proxy_redirect      http://jenkins_master:8080 https://<hostname.example.com>;

    # Required for new HTTP-based CLI
    proxy_http_version 1.1;
    proxy_request_buffering off;
    proxy_buffering off;
    add_header 'X-SSH-Endpoint' '<hostname.example.com>:50000' always;
  }
}

NOTE: You will need to replace <hostname.example.com> with your server DNS name. Place the jenkins.conf under nginx\conf.d

The next step will be to generate an SSL certificate and a private key. You can generate a self-signed certificate and key using the command below:

openssl req -newkey rsa:2048 -keyout jenkins.key -x509 -days 365 -out jenkins.crt

Else you can provide your SSL certificate or generate one using letsencrypt Place the jenkins.key and jenkins.crt files under nginx\certs

Docker-compose set up

The bellow docker-compose file will:

• Pull the latest official Docker containers of Jenkins master and Nginx.
• Set up a base configuration for both containers.
• Mount volumes in a way that will persist data.
• Expose the correct containers ports.
• Set jenkins master time zone.

version: '3.7'
services:
  jenkins_master:
    user: root
    image: jenkins/jenkins:lts
    pull_policy: always
    container_name: jenkins-server
    volumes:
      - ./jenkins_home:/var/jenkins_home
      - ./jenkins_log:/var/log/jenkins
      - /var/run/docker.sock:/var/run/docker.sock
      - /usr/local/bin/docker:/usr/local/bin/docker
    ports:
      - 50000:50000
      - 50022:50022
    expose:
      - 8080
    environment:
      JAVA_OPTS: "-Djenkins.install.runSetupWizard=false -Djava.awt.headless=true"
      TZ: "Canada/Eastern"
    networks:
      - jenkins_nw
    restart: unless-stopped
  nginx:
    image: "nginx:latest"
    ports:
      - 80:80
      - 443:443
    container_name: nginx-proxy
    volumes:
      - ./nginx/certs:/etc/ssl
      - ./nginx/conf.d:/etc/nginx/conf.d
      - ./nginx_log:/var/log/nginx/jenkins
      - /var/run/docker.sock:/tmp/docker.sock:ro
    networks:
      - jenkins_nw
    depends_on:
      - jenkins_master
    restart: unless-stopped

networks:
  jenkins_nw:
    driver: bridge

Run the containers

To start your jenkins master and nginx containers run the command:

docker-compose up

Github Repo

You can find the project repository here.

Questions and comments are welcome. Please share, if this helped you.