Microservice architectures have many advantages. These include separate continuous deployments, resilience, easy scalability, and the ability to use different technology stacks for each microservice.Now servers are talking to each other, so you must give permission and check authorization. They also add complexity in the security in how you manage authentication & authorization between microservices.
At its core it is not too different from client and server authentication. Except now servers are communicating with each other and you need to make sure you grant access and perform authorization checks.
There are many approaches you can use. In this blog post, we will talk about three common patterns and explain their benefits. We will also provide examples of when to use these patterns and when to avoid them. After reading this blog you should have a good overview of how authentication and authorization works in microservices.
An API Gateway handles all incoming requests in front of the microservices. It uses JSON Web Tokens (JWT) to pass user identity and claims. The API Gateway authenticates requests and sends them to the correct microservice. It also manages, authorization, rate limiting, and logging. This centralized system makes interactions between clients and backend services easier.
Users authenticate with an identity provider (IdP) which issues a JWT. The system then passes the JWT with each request. Microservices validate the JWT and extract user claims for authorization.
A central IAM system manages authentication and authorization. Microservices ask the IAM system for user permissions and roles. This setup is common in environments with complex authorization needs.
1. Centralized Authentication:
An API Gateway handles authentication for all requests using JSON Web Tokens (JWT). This makes each microservice simpler.
2. Simplified Client Use:
Clients use one endpoint (the API Gateway) instead of many. This simplifies client-side logic and reduces connections.
3. Better Security:
The API Gateway is a single entry point, making it easier to enforce security and detect threats. It protects the internal system from direct client access.
4. Load Balancing:
The API Gateway distributes traffic across microservices, providing load balancing and improving system resilience. It handles high traffic well.
5. Consistent Logs and Monitoring:
With an API Gateway, logging and monitoring are consistent. It captures detailed metrics and logs, helping to monitor performance and fix issues.
1. Multiple Microservices Handling Similar Requests:
When your architecture has many services, an API gateway can reduce the complexity of handling multiple endpoints.
Example: In an e-commerce platform, an API Gateway routes requests to the user service, product service, and order service. This centralizes access control and simplifies client interactions.
2. Need for Centralized Security and Rate Limiting:
If your microservices architecture needs strong security, rate limiting, and traffic management, an API Gateway is essential. It ensures these policies are enforced consistently across all services.
In a SaaS app, the API Gateway can limit usage based on the user's subscription. This helps prevent misuse and ensures fair resource sharing. Different service levels may have different restrictions. The API Gateway enforces these restrictions to maintain fairness among users.
3. Simplifying Client Development:
If you want to make client development easier with one API endpoint, an API Gateway is the solution. This abstraction layer hides the complexity of the underlying microservices from the client.
For a mobile app that uses multiple backend services, an API Gateway simplifies the process. It reduces the number of endpoints and authentication steps needed on the client side.
4. Implementing Cross-Cutting Concerns:
Cross-cutting concerns like logging, monitoring, and authentication are easier to manage with an API Gateway. It provides a centralized place to implement these functions, ensuring consistency across the system.
A financial application needs detailed audit logs to comply with rules. An API Gateway logs each request and response, ensuring consistent recording of all actions.
1. Small, Simple Projects:
For small projects with few microservices, setting up an API Gateway may not be worth it.
2. Low Latency Needs:
If your app needs very low delay, an API Gateway can slow it down.
3. Direct Communication:
Sometimes, clients should talk directly to microservices to avoid bottlenecks.
1. Decentralized Authentication and Authorization:
Token-based authentication lets each microservice check tokens on its own. This removes the need for a central server and makes the system stronger.
2. Statelessness:
Tokens, like JWTs, are self-contained and don't need a central store. This makes the system simpler.
3. Scalability:
By checking tokens locally, microservices can handle authentication without a central server, improving scalability. This helps in systems where services need to grow on their own.
4. Interoperability:
Tokens work across different systems and technologies. This makes it easy to connect with third-party services.
1. Web and Mobile Apps with Many Microservices:
When apps have many microservices, use token-based authentication. Users log in once and use many services easily.
Example: A website where one account lets users access profiles, messages, and news feeds. Each service checks the token for personalized experiences.
2. Stateless and Spread-Out Systems:
Token-based authentication works well in stateless, spread-out systems. Services work without a central session system.
Example: A CDN uses edge servers to check tokens and give personalized content without a central server.
3. APIs for Third Parties:
Token-based authentication lets third-party developers access APIs securely and manage access well. It provides a safe way to interact with APIs.
Example: A fintech platform with an API for third-party developers. They use tokens with permissions for secure access.
4. High Scalability and Performance:
For high scalability and low delay, token-based authentication helps. Tokens are checked quickly locally, reducing delay from server calls.
Example: An online gaming platform where performance is key. Players log in once, and game servers check tokens for smooth gaming.
1. Complex Access Control Requirements:
If your application requires complex, hierarchical, or conditional access control policies, a centralized IAM system might be more appropriate.
2. High Security Environments:
In places with strict security needs, managing and securing tokens, especially long-lasting ones, can be difficult. mTLS or other methods might be more secure.
3. Frequent Token Management:
Applications that require frequent token revocation, renewal, or detailed session management may find token-based authentication cumbersome compared to session-based methods.
1. Centralized Control:
IAM systems act as a central authorization server that manages for user identities, roles, and permissions. This centralization simplifies the administration of access controls across a large number of services.
2. Fine-Grained Access Control:
IAM systems support detailed and complex access control policies, enabling fine-grained management of user permissions. This is important in environments where administrators must tightly control and monitor access.
3. Integration with Enterprise Systems:
IAM solutions can easily integrate with large business identity and security systems. This ensures a secure and consistent method for managing user access to various applications and services.
4. Enhanced Security and Compliance:
Centralized IAM systems offer robust security features, such as multi-factor authentication (MFA), auditing, and compliance reporting. These features help organizations meet regulatory requirements and enforce stringent security policies.
1. Complex Authorization Needs:
Big businesses often have complex access needs. A central IAM system can manage these well.
Example: A large company with departments like HR and IT needing different access. An IAM system ensures only approved staff access specific data.
2. Regulatory Requirements:
Organizations under strict rules (e.g., GDPR, HIPAA) benefit from central IAM systems that provide detailed auditing.
Example: A healthcare provider using an IAM system to control patient records. Only authorized staff see sensitive info, meeting HIPAA rules.
3. Large Apps with Many Microservices:
Managing access for many microservices can be tough. A central IAM system makes this easier.
Example: A financial institution with microservices for transactions and accounts. The IAM system manages roles and permissions centrally.
4. Detailed Role-Based Access Control:
IAM systems help by defining and enforcing role hierarchies and permissions.
Example: A school where students, teachers, and admins need different access. The IAM system manages these roles and ensures correct access.
1. Small, Simple Applications:
For small projects that don't need much access control, setting up and managing an IAM system may not be worth it.
2. Low Latency Requirements:
If your app requires high speed, making additional network calls to verify permissions in the IAM system may lead to delays. This is because each network call takes time to process and can slow down the overall performance of the app. To avoid these delays, it is important to streamline the permission checking process within the app itself. You can keep your app fast and responsive by reducing the number of network calls for permission checks.
3. Decentralized and Stateless Environments:
Token-based authentication is a good choice for environments that prioritize statelessness and decentralization. It allows for local validation of tokens without needing a central system.
In conclusion, choose between an API Gateway, token-based authentication, or centralized IAM systems based on your project's needs. API Gateways simplify security for many microservices, good for complex systems needing central control. Token-based authentication is decentralized and scalable, ideal for fast, stateless applications. Centralized IAM systems offer strong access control for large organizations with complex needs. Use this overview to decide the best approach for your application.