Getting Started with Keycloak: Running Your First Instance

As developers, we often face the challenge of implementing secure authentication and authorization in our applications. Keycloak is an open-source Identity and Access Management solution that can significantly simplify this process. In this first part of our three-part series, we'll set up a Keycloak instance using Docker.
Prerequisites

Docker installed on your machine
Basic understanding of authentication concepts
Terminal/Command Prompt access

Setting Up Keycloak with Docker

First, let's create a docker-compose.yml file:

version: '3'
services:
  keycloak:
    image: quay.io/keycloak/keycloak:22.0.1
    environment:
      - KEYCLOAK_ADMIN=admin
      - KEYCLOAK_ADMIN_PASSWORD=admin
    ports:
      - "8080:8080"
    command:
      - start-dev

Start the container:

docker-compose up -d

Your Keycloak instance will be available at http://localhost:8080.
Configuring Keycloak

Navigate to http://localhost:8080/admin and log in with:

Username: admin
Password: admin

Create a new realm:

Click Create Realm
Name it demo-realm
Click Create

Create a client for our applications:

Go to Clients → Create client
Client ID: demo-app
Client Protocol: openid-connect
Click Next
Enable Client authentication
Click Save

Configure the client:

Valid redirect URIs:

http://localhost:8081/* (for Spring Boot)
http://localhost:4200/* (for Angular)

Web Origins:

http://localhost:8081
http://localhost:4200

Click Save

Create a test user:

Go to Users → Add user
Username: testuser
Email: [e-mail]
Click Create
Go to Credentials tab
Set password: password123
Disable Temporary
Click Set Password

Important Configuration Values
Save these values for the next parts:
plaintextCopyRealm: demo-realm
Client ID: demo-app
Client Secret: (find in Clients → demo-app → Credentials tab)
Auth URL: http://localhost:8080/realms/demo-realm
Testing the Setup

Visit http://localhost:8080/realms/demo-realm/.well-known/openid-configuration
You should see a JSON document with endpoint configurations

In the next part, we'll integrate this Keycloak instance with a Spring Boot application.
Stay tuned for Part 2: Integrating Keycloak with Spring Boot!