stefan
9282dd0eb4
1. **Dokumentation der Architektur:**
- Vervollständigen Sie die C4-Diagramme im docs-Verzeichnis
- Dokumentieren Sie die wichtigsten Architekturentscheidungen in ADRs
2. **Redis-Integration finalisieren:**
- Implementieren Sie die verteilte Cache-Lösung für die Offline-Fähigkeit
- Nutzen Sie Redis Streams für das Event-Sourcing
4.0 KiB
ADR-0006: Authentication and Authorization with Keycloak
Status
Accepted
Context
As part of our microservices architecture (ADR-0003), we needed a robust and centralized solution for authentication and authorization. Key requirements included:
- Single sign-on (SSO) across all services and applications
- Support for multiple authentication methods (username/password, OAuth, SAML)
- Fine-grained authorization with role-based access control (RBAC)
- User management capabilities including self-registration and profile management
- Integration with external identity providers
- Security best practices including password policies and account lockout
- Token-based authentication for service-to-service communication
Implementing these features from scratch would be time-consuming and error-prone, and would divert resources from our core business functionality.
Decision
We decided to use Keycloak (version 23.0) as our identity and access management solution. Keycloak is an open-source identity and access management solution that provides:
- User Authentication: Multiple authentication methods and flows
- User Federation: Integration with LDAP, Active Directory, and other user stores
- Identity Brokering: Integration with external identity providers (Google, Facebook, etc.)
- Single Sign-On: Across all applications and services
- Fine-grained Authorization: Role-based and attribute-based access control
- User Management: Self-registration, profile management, password policies
- Token-based Authentication: JWT tokens for service-to-service communication
Our implementation includes:
- Keycloak server deployed as a containerized service
- Integration with our API Gateway for token validation
- Client adapters for our services and applications
- Custom themes and email templates
- Role and group definitions aligned with our domain model
Consequences
Positive
- Comprehensive solution: Keycloak provides a complete identity and access management solution
- Standards compliance: Keycloak implements industry standards (OAuth 2.0, OpenID Connect, SAML)
- Reduced development effort: We don't need to implement authentication and authorization from scratch
- Security: Keycloak follows security best practices and is actively maintained
- Flexibility: Keycloak supports multiple authentication methods and identity providers
Negative
- Operational complexity: Keycloak adds another service to deploy and maintain
- Learning curve: Teams need to learn Keycloak concepts and APIs
- Performance considerations: Token validation adds some overhead to requests
- Dependency: We are dependent on Keycloak for authentication and authorization
Neutral
- Configuration needs: Keycloak requires careful configuration to align with our security requirements
- Upgrade management: Keycloak upgrades need to be managed carefully
Alternatives Considered
Custom Authentication Service
We considered building our own authentication service. This would have given us complete control over the implementation but would have required significant development effort and ongoing maintenance.
Auth0
We considered using Auth0, a commercial identity as a service (IDaaS) solution. Auth0 would have provided similar capabilities to Keycloak with less operational overhead, but would have introduced ongoing costs and potential vendor lock-in.
Spring Security with JWT
We considered using Spring Security with JWT tokens for authentication and authorization. This would have integrated well with our Spring-based services but would have required more development effort and would not have provided the comprehensive identity management features of Keycloak.