Introduction

Providing OAuth 2.0 user authentication directly or using Google+ Sign-in helps us to achieve a modern authentication method. It also provides a trusted and secure login system that’s familiar to users, consistent across devices, and removes the burden of users having to remember another username and password. One of the hurdles in implementing a Gmail authentication is that the Google developer console and your Jenkins server should be in the same network or in simple terms they can talk to each other.

What is SSO ?

SSO stands for Single Sign-On, which is a method of authentication that allows users to access multiple applications and services with a single set of login credentials.

With SSO, users are only required to enter their login credentials once, and they can then access all the applications and services that are part of the SSO system. This simplifies the authentication process, improves user experience, and reduces the risk of security breaches.

Introduction

Providing OAuth 2.0 user authentication directly or using Google+ Sign-in reduces your CI overhead. It also provides a trusted and secure login system that’s familiar to users, consistent across devices, and removes the burden of users having to remember another username and password. One of the hurdles in implementing a Gmail authentication is that Google developer console and your Jenkins server should be in the same network or in simple terms they can talk to each other.

Resources Used

Privately Hosted Jenkins
Google developer console
Ngrok

In this blog, I’m trying to explain how to integrate Gmail authentication feature in your privately hosted Jenkins server so that you get free of filling the form by the time of creating a new user.

Setup 1: Setup Ngrok

NGROK

Ngrok is multiplatform tunneling, reverse proxy software that establishes secure tunnels from a public endpoint such as the internet to a locally running network service while capturing all traffic for detailed inspection and replay.

We are using Ngrok to host our Jenkins service (running on port 8080) to public IP.

Go to google and search for Download Ngrok.

Either Login with google account or do Ngrok own signup.

After Logged in Ngrok Download it.

After Download Ngrok, Go to the console and unzip the downloaded zip file and then move it to /usr/local/bin.

Note: Moving part is optional, we do so for accessing ngrok from anywhere.

Go to ngrok UI page , copy the authentication key and paste it.

Note: Remove ” . / ” sign because we moved ngrok file to /usr/local/bin

Major configuration for Ngrok is done. Now type the command:

ngrok http 8080

Assuming that Jenkins is running on port 8080.

Now Ngrok Host our Jenkins Service to public IP.

Copy this IP, we will use it in the google developer console.

Note: Make this terminal up and running.(don’t do ctrl+c)

Step 2: Setup Google Developer Console

Go to google and search for google developer console.

After sign in into google developer console, we will redirect to Google developer console UI screen.

Go to Select a project → New Project

Give Project Name, here I will use “JenkinsGmailAuthentication” and create a project. Creating a project takes 1 or 2 minutes.

After Project created, we will be redirected to the UI page as shown below. Now click on on the “Credentials” Tab on the left slide bar.

After Go to the OAuth consent screen tab and give the below entries. Here I will give Application name to “JenkinsGmailAuthentication”.

The important part of the Google developer console is Public IP we created using Ngrok. Copy Public IP in Authorized domains and note to remove ” http:// ” in Authorized domains.