Develop User Identity Module with Keycloak Authentication in .NET Modular Monoliths Architecture

5 min readSep 3, 2024

We are diving into setting up a user identity module using Keycloak for our application.

**Keycloak Authentication in .NET Modular Monoliths Architecture**

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This guide will walk you through the essentials of integrating Keycloak as an Identity and Access Management (IAM) solution in a modular monolithic architecture.

What is Keycloak?

Keycloak is an open-source Identity and Access Management (IAM) solution designed for modern applications and services. It offers a comprehensive suite of features for authentication and authorization with minimal coding effort required.

Single Sign-On (SSO): Users can log in once and gain access to multiple applications without needing to reauthenticate. This feature greatly enhances user experience by reducing the need to remember multiple sets of credentials.
Identity Brokering and Social Login: Keycloak supports integration with external identity providers, such as Google, Facebook, and GitHub, allowing users to log in using their existing accounts on these platforms.
User Federation: Connects Keycloak to existing user databases like LDAP or Active Directory, enabling seamless integration with existing user stores.
Centralized Management: Provides a unified management console for managing users, roles, and permissions, streamlining the administration process.
Standard Protocols: Supports industry-standard protocols like OAuth 2.0, OpenID Connect, and SAML 2.0, ensuring compatibility with a wide range of applications.

Key Features

Single Sign-On (SSO): Simplifies the user experience by allowing one-time authentication for multiple applications.
Identity Brokering and Social Login: Easily integrates with third-party identity providers.
User Federation: Connects to existing user databases for streamlined user management.
Centralized Management: Manages user identities and permissions from a single interface.
Standard Protocols: Supports OAuth 2.0, OpenID Connect, and SAML 2.0 for secure authentication and authorization.

Why Use Keycloak?

Integrating Keycloak into your application can significantly reduce the complexity of managing user identities and access controls. Here’s why:

Security: Keycloak provides robust security features that adhere to industry standards, ensuring that your application is well-protected against unauthorized access.
Scalability: It is capable of handling millions of users and requests, making it suitable for both small applications and large-scale enterprises.
Flexibility: Keycloak is highly flexible, allowing for easy integration with various applications and services, whether you are using standard protocols or need a custom setup.
User Experience: Enhances user experience with features like SSO and social login, making it easier for users to access multiple services seamlessly.

Keycloak is a powerful tool that simplifies identity and access management. By leveraging its features, we can enhance the security and user experience of our applications.

Practical Scenarios with Keycloak

Let’s discuss some practical scenarios where Keycloak can be effectively integrated into your applications:

Scenario 1: Single Sign-On (SSO)

Implementing SSO with Keycloak allows users to authenticate once and gain access to multiple applications without re-entering their credentials.

Configure Clients: Register all applications as clients in Keycloak.
Enable SSO: Ensure all clients use the same realm for authentication.
User Experience: Users log in through a single sign-on portal and access all configured applications seamlessly.

Scenario 2: Social Login

Keycloak supports identity brokering, allowing users to log in using their social media accounts.

Add Identity Provider: In the Keycloak Admin Console, add an identity provider (e.g., Google, Facebook).
Configure Client: Set up the client with the necessary redirect URIs and credentials.
Login Flow: Users log in using their social media accounts, and Keycloak handles the authentication process.

Scenario 3: User Federation

Keycloak can connect to existing user databases, such as LDAP or Active Directory.

Add User Federation Provider: In the Keycloak Admin Console, add a user federation provider.
Configure Connection: Enter the connection details for the external user database.
Synchronization: Keycloak synchronizes users from the external database, allowing seamless integration.

Integrating Keycloak with Docker Compose

Now, let’s see how to set up Keycloak as an identity provider using Docker Compose. This will allow us to easily manage our Keycloak deployment and integrate it with other services.

Step 1: Docker Compose Configuration

First, add the Keycloak service to your docker-compose.yml file.

version: '3.4'
services:
  keycloak:
    image: quay.io/keycloak/keycloak:24.0.3
    container_name: keycloak
    environment:
      - KEYCLOAK_ADMIN=admin
      - KEYCLOAK_ADMIN_PASSWORD=admin
    ports:
      - "9090:8080"
    command:
      - start-dev
    restart: always

Image: Uses the official Keycloak image from quay.io.
Environment: Sets up environment variables for the admin username and password.
Ports: Maps port 8080 inside the container to port 9090 on the host, making the Keycloak admin console accessible via http://localhost:9090.
Command: start-dev is used to start Keycloak in development mode, simplifying the setup process for development environments.

Step 2: Running Keycloak with Docker Compose

To start Keycloak with Docker Compose, run the following command:

docker-compose up -d

This command will start Keycloak as a service, and you can access the admin console at http://localhost:9090.

Summary

In this article, we covered the following key points:

Introduction to Keycloak: We learned what Keycloak is and its key features.
Benefits of Using Keycloak: We discussed why Keycloak is beneficial for managing user identities and access controls.
Practical Scenarios: We explored practical scenarios where Keycloak can be integrated into applications.
Integrating Keycloak with Docker Compose: We went through the steps to set up Keycloak using Docker Compose.