Setting up Identity and Access Management (IAM) can be daunting, especially when you’re dealing with multiple applications and users. Keycloak, an open-source IAM solution, simplifies this process by providing robust authentication and authorization capabilities. In this guide, I’ll walk you through the basics of getting started with Keycloak, covering everything from setting up your first realm to integrating it with your applications.

Understanding the Problem

Before diving into Keycloak, let’s understand why IAM is crucial. Imagine managing access to multiple applications across different teams. Without a centralized system, you’d need to handle user management, authentication, and authorization separately for each application. This leads to inconsistencies, security risks, and increased administrative overhead. Keycloak addresses these issues by providing a unified platform for managing identities and access.

Setting Up Your First Realm

A realm in Keycloak is a container for all the data, including users, roles, and clients. Think of it as a separate instance of Keycloak dedicated to a specific group of users or applications.

Step-by-Step Guide

Install Keycloak

You can run Keycloak using Docker for simplicity. Here’s how:
Terminal
$ docker run -p 8080:8080 jboss/keycloak:latest

Create a New Realm

1. Open your browser and navigate to `http://localhost:8080`. 2. Log in with the default admin credentials (`admin/admin`). 3. Click on "Create" and enter a name for your realm (e.g., `myrealm`).
💡 Key Point: Always change the default admin password after your first login.

Configure Users

1. Go to the "Users" tab and click "Add User". 2. Fill in the required fields (username, email, etc.) and save. 3. Set a password for the user by navigating to the "Credentials" tab.
⚠️ Warning: Ensure passwords are strong and unique to prevent unauthorized access.

Set Up Clients

1. Navigate to the "Clients" tab and click "Create". 2. Enter a client ID (e.g., `myapp`) and select the client protocol (usually `openid-connect`). 3. Configure client settings such as redirect URIs and web origins.
💜 Pro Tip: Redirect URIs should match the URLs your application will use for callbacks.

🎯 Key Takeaways

  • A realm is a container for all your data in Keycloak.
  • Use Docker for a quick setup of Keycloak.
  • Always secure your admin credentials.

Differences Between Clients and Users

Understanding the distinction between clients and users is fundamental to effectively managing Keycloak.

Clients

Clients represent applications or services that interact with Keycloak for authentication and authorization. They are configured with various settings such as client IDs, protocols, and redirect URIs.

Example Configuration

# Client configuration example
client_id: myapp
protocol: openid-connect
redirect_uris:
  - http://localhost:3000/callback
web_origins:
  - http://localhost:3000

Users

Users are individuals who authenticate with Keycloak to access protected resources. Each user has attributes like username, email, and password, and can be assigned roles and groups.

Example User Attributes

# User attributes example
username: johndoe
email: [email protected]
enabled: true
attributes:
  phone_number: +1234567890

🎯 Key Takeaways

  • Clients are applications that interact with Keycloak.
  • Users are individuals who authenticate with Keycloak.

Integrating Keycloak with Your Application

Integrating Keycloak with your application involves configuring the client settings and implementing authentication and authorization logic in your code.

Step-by-Step Guide

Configure Client Settings

1. Go to the "Clients" tab in Keycloak. 2. Select your client and configure the necessary settings: - Valid Redirect URIs - Web Origins - Client Authentication 3. Save the changes.
💜 Pro Tip: Use client secrets for confidential clients to enhance security.

Implement Authentication

Use Keycloak’s SDK or libraries to implement authentication in your application. Here’s an example using Node.js with `keycloak-connect`.
Terminal
$ npm install keycloak-connect express 
// Example of setting up Keycloak in a Node.js application
const express = require('express');
const session = require('express-session');
const Keycloak = require('keycloak-connect');

const memoryStore = new session.MemoryStore();

const keycloakConfig = {
  clientId: 'myapp',
  bearerOnly: true,
  serverUrl: 'http://localhost:8080/auth',
  realm: 'myrealm',
  credentials: {
    secret: 'your-client-secret'
  }
};

const keycloak = new Keycloak({ store: memoryStore }, keycloakConfig);

const app = express();
app.use(session({
  secret: 'some-secret',
  resave: false,
  saveUninitialized: true,
  store: memoryStore
}));
app.use(keycloak.middleware());

app.get('/', keycloak.protect(), (req, res) => {
  res.send('Hello, ' + req.kauth.grant.access_token.content.preferred_username);
});

app.listen(3000, () => {
  console.log('App listening on port 3000');
});
🚨 Security Alert: Never hard-code sensitive information like client secrets in your source code. Use environment variables instead.

Handle Authorization

Define roles and permissions in Keycloak and check them in your application. 
// Example of role-based authorization
app.get('/admin', keycloak.protect('realm:admin'), (req, res) => {
  res.send('Welcome, Admin!');
});

🎯 Key Takeaways

  • Configure client settings in Keycloak for your application.
  • Use Keycloak SDKs or libraries to implement authentication and authorization.
  • Define roles and permissions for fine-grained access control.

Troubleshooting Common Issues

Running into issues is common, especially during the initial setup. Here are some common problems and their solutions.

Error: Invalid Redirect URI

Cause: The redirect URI configured in Keycloak does not match the one used by your application.

Solution: Ensure that the redirect URIs in Keycloak match those used by your application.

Error: Unauthorized Client

Cause: The client ID or client secret is incorrect.

Solution: Verify that the client ID and client secret in your application match those configured in Keycloak.

Error: Invalid Token

Cause: The access token is expired or invalid.

Solution: Refresh the token or re-authenticate the user.

🎯 Key Takeaways

  • Check redirect URIs for mismatches.
  • Verify client ID and secret.
  • Refresh tokens as needed.

Conclusion

Keycloak is a powerful open-source IAM solution that simplifies identity and access management for your applications. By following this guide, you should have a solid foundation for setting up and managing Keycloak in your environment. Remember to keep your configurations secure and regularly update your Keycloak instance to benefit from the latest features and security patches.

That’s it. Simple, secure, works. Happy coding!

📋 Quick Reference

  • docker run -p 8080:8080 jboss/keycloak:latest - Run Keycloak using Docker
  • keycloak.protect() - Protect routes in your application
  • keycloak.protect('role') - Protect routes based on roles