Configure Jenkins using Nginx Reverse Proxy on Ubuntu 22.04 on AWS

Introduction:

In this post, we will be installing Jenkins on an EC2 instance running Ubuntu, and configuring a reverse proxy using Nginx. I have used the t3.small instance and hosted my domain on Route 53.

Jenkins is a popular open-source automation server used for continuous integration and continuous delivery (CI/CD) pipelines. By installing Jenkins on an EC2 instance, we can leverage the scalability and flexibility of AWS to automate our development and deployment processes.

Configuring a reverse proxy using Nginx is a common way to improve security and performance when serving web applications

Install Jenkins:

Update Package Repository and Upgrade Packages:
```
  sudo apt update
  sudo apt upgrade
```

Install Adoptium Java 17, Add Adoptium Repository

  wget -O - <https://packages.adoptium.net/artifactory/api/gpg/key/public> | tee /etc/apt/keyrings/adoptium.asc

  echo "deb [signed-by=/etc/apt/keyrings/adoptium.asc] <https://packages.adoptium.net/artifactory/deb> $(awk -F= '/^VERSION_CODENAME/{print$2}' /etc/os-release) main" | tee /etc/apt/sources.list.d/adoptium.list

Update the Repo and Add Java 17

  apt update
  apt install temurin-17-jdk
  /usr/bin/java --version
  exit

Now it's time to install Jenkins. First, add the repository key to the system:

  curl -fsSL <https://pkg.jenkins.io/debian-stable/jenkins.io-2023.key> | sudo tee \\
    /usr/share/keyrings/jenkins-keyring.asc > /dev/null
  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
  sudo apt-get update
  sudo apt-get install jenkins

It's time to start Jenkins.
```
  sudo systemctl start jenkins
```
To ensure that Jenkins is running properly, it is important to verify that it has started successfully. As systemctl does not display status output, we need to rely on the status command to check the status of Jenkins. By using the status command, we can confirm that Jenkins has started and is running without any issues.
```
  sudo systemctl status jenkins
```
If everything is working correctly, the status output at the beginning will indicate that the service is currently active and set to start automatically during boot.
Access Jenkins User Interface

To set up your installation, access Jenkins on its default port, 8080, by using your server's domain name or IP address: http://your_server_ip_or_domain:8080

Install Nginx Reverse Proxy for Jenkins:

Nginx is a highly popular and widely used web server that can host some of the biggest and most visited sites on the internet. It is a lightweight option that can function as either a web server or reverse proxy. Due to its versatility, it provides a great deal of flexibility to its users. Nginx is designed to efficiently handle a large number of concurrent connections, which makes it an excellent choice for high-traffic websites. It is well-known for its high performance, stability, and scalability. Nginx can be easily configured and customized according to the user's needs.

📌 Prerequisites: Jenkins server already installed and running

Update Package Repository and Upgrade Packages
```
  sudo apt update
  sudo apt upgrade
```
Installing Nginx
```
  sudo apt install nginx
```
Checking Your Web Server

To confirm that the service is running, type the following command using the systemd init system:
```
  systemctl status nginx
```
We can check with the systemd init system to make sure the service is running by typing:
Check your Web Server is running
```
  http://your_server_ip
```
We need to see this output:

Configuring as Reverse proxy - Nginx Go to the directory /etc/nginx/conf.d and create a file named jenkins.conf, And paste the following content:

  upstream jenkins {
    keepalive 32; # keepalive connections
    server 127.0.0.1:8080; # jenkins ip and port
  }

  # Required for Jenkins websocket agents
  map $http_upgrade $connection_upgrade {
    default upgrade;
    '' close;
  }

  server {
    listen          80;       # Listen on port 80 for IPv4 requests

    server_name     jenkins.nishanthgowda.xyz;  # replace this with your server domain name

    # this is the jenkins web root directory
    # (mentioned in the output of "systemctl cat jenkins")
    root            /var/cache/jenkins/war/;

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

    # pass through headers from Jenkins that Nginx considers invalid
    ignore_invalid_headers off;

    location ~ "^/static/[0-9a-fA-F]{8}\\/(.*)$" {
      # rewrite all static files into requests to the root
      # E.g /static/12345678/css/something.css will become /css/something.css
      rewrite "^/static/[0-9a-fA-F]{8}\\/(.*)" /$1 last;
    }

    location /userContent {
      # have nginx handle all the static requests to userContent folder
      # note : This is the $JENKINS_HOME dir
      root /var/lib/jenkins/;
      if (!-f $request_filename){
        # this file does not exist, might be a directory or a /**view** url
        rewrite (.*) /$1 last;
        break;
      }
      sendfile on;
    }

    location / {
        sendfile off;
        proxy_pass         <http://jenkins>;
        proxy_redirect     default;
        proxy_http_version 1.1;

        # Required for Jenkins websocket agents
        proxy_set_header   Connection        $connection_upgrade;
        proxy_set_header   Upgrade           $http_upgrade;

        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_max_temp_file_size 0;

        #this is the maximum upload size
        client_max_body_size       10m;
        client_body_buffer_size    128k;

        proxy_connect_timeout      90;
        proxy_send_timeout         90;
        proxy_read_timeout         90;
        proxy_buffering            off;
        proxy_request_buffering    off; # Required for HTTP CLI commands
        proxy_set_header Connection ""; # Clear for keepalive
    }

  }

Next, check for syntax errors in your Nginx files to ensure they are error-free. Run the following command.
```
  sudo nginx -t
```

You should get a similiar output:

  nginx: the configuration file /etc/nginx/nginx.conf syntax is ok
  nginx: configuration file /etc/nginx/nginx.conf test is successful

Now, to ensure that the changes made to the nginx configuration file are reflected, we need to restart the nginx service:
```
  sudo systemctl restart nginx
```
Now, you can see Jenkins up and running through the NGINX server.
Under Manage Jenkins, we can get the below error in some cases.
To fix this error, you can go to the "Configure System" section under "Manage Jenkins". In this section, find the "Jenkins Location" setting and update the URL to match your custom URL. This should resolve the error and allow Jenkins to be accessed using your custom URL.
Now that you've configured Nginx to act as a reverse proxy for Jenkins, you should be able to access Jenkins by navigating to your domain name. Simply enter your domain name into your web browser's address bar and hit enter to test this. If everything has been set up correctly, you should be able to access Jenkins from your domain name without any issues.

Conclusion:

In conclusion, we have successfully installed Jenkins on an EC2 instance running Ubuntu, and configured a reverse proxy using Nginx. By hosting our domain on Route 53, we were able to easily manage DNS records and route traffic to our EC2 instance. With these tools in place, we have created a robust and scalable infrastructure for our Jenkins deployment.

Jenkins is a powerful automation server that can help streamline our development and deployment processes. By using AWS, we can take advantage of the scalability and flexibility of cloud computing to create a reliable and secure Jenkins deployment.

I hope that this tutorial has helped guide you through the process of installing Jenkins and configuring Nginx as a reverse proxy. With this knowledge, you can now create a powerful CI/CD pipeline that can help automate your development and deployment workflows.

Configure Jenkins using Nginx Reverse Proxy on Ubuntu 22.04 on AWS

A quick guide to configure jenkins using Nginx Reverse Proxy on Ubuntu 22.04 on AWS

Table of contents

Introduction:

Install Jenkins:

Install Nginx Reverse Proxy for Jenkins:

Conclusion: