Microservices patterns questions and answers - English

Sure, here are some questions and answers related to microservices patterns:

Q1: What is the Microservices Architecture pattern?

A1: The Microservices Architecture pattern is a method for developing software systems that focuses on creating single-function modules with well-defined interfaces and operations. Each service is a small, self-contained unit that performs a specific functionality and can be independently deployed, scaled, and updated.

Q2: What is the API Gateway pattern in microservices?

A2: The API Gateway pattern acts as a single point of entry for all the client requests. It is responsible for request routing, composition, and protocol translation. It provides each of the application's clients with a custom API.

Q3: Can you explain the Database per Service pattern?

A3: The Database per Service pattern is a microservice database architecture that assigns a dedicated database to each microservice. This allows the services to be loosely coupled and evolve independently, but it also introduces challenges for data consistency and integrity across multiple services.

Q4: What is Event-Driven Data Management in microservices?

A4: Event-Driven Data Management is a pattern where services publish events when their data changes, and other services consume those events to update their own data. This pattern can help maintain data consistency across different services in a microservices architecture, especially when using the Database per Service pattern.

Q5: What is the Saga pattern?

A5: The Saga pattern is a design pattern that provides a way to manage and coordinate distributed transactions across multiple services. A Saga is a sequence of local transactions where each transaction updates data within a single service. If one transaction fails, the Saga executes compensating transactions to undo the impact of the preceding transactions.

Q6: What is the Circuit Breaker pattern?

A6: The Circuit Breaker pattern is a design pattern used in microservices to prevent a network or service failure from cascading to other services. When a service is unavailable or the response time from the service exceeds a certain threshold, the Circuit Breaker is tripped and future calls to the service are blocked until the service recovers.

Q7: What is the Service Registry and Discovery pattern?

A7: In microservices, the Service Registry and Discovery pattern is a way for services to register themselves and discover other services upon startup. The Service Registry acts as a database of services, their instances, and locations. Service Discovery is a mechanism for services to find and communicate with each other without knowing their exact network locations.

Q8: What is the Sidecar pattern in microservices?

A8: The Sidecar pattern in microservices is a type of single-node application decomposition pattern where an application and a sidecar container are packaged together as a single unit and share the same lifecycle. The sidecar container can provide additional functionalities such as monitoring, logging, configuration, etc., thus allowing the application to focus on business logic.

Q9: What is the Strangler Fig pattern?

A9: The Strangler Fig pattern is a design approach for migrating a monolithic system to a microservices architecture. Rather than attempting to completely rewrite the entire system, a new system is slowly built around the edges of the old system. Over time, the new system replaces parts of the old system until the entire system has been migrated.

Q10: What is the CQRS (Command Query Responsibility Segregation) pattern?

A10: CQRS is a pattern that segregates the operations that read data (Queries) from the operations that update data (Commands) into different models. This allows each model to be optimized for its specific type of operation. It also ensures that the responsibility of commands and queries is clearly separated.

Q11: What is the Serverless Deployment pattern?

A11: The Serverless Deployment pattern is a model where the service provider manages the server infrastructure, and you only pay for the compute time that you consume. This can be a good fit for microservices, as individual services can be deployed as serverless functions, allowing them to scale independently based on demand.

Q12: What is the Backend for Frontend (BFF) pattern?

A12: The Backend for Frontend (BFF) pattern is a design approach where a client-facing microservice tailors a user interface experience for each type of client device (e.g., desktop, mobile, tablet, etc.) It acts as a gateway for a specific user experience, shaping and combining data sources to meet the exact needs of the client.

Q13: What is the Composite Microservices pattern?

A13: Composite Microservices pattern is an approach where individual microservices that have their own unique database tables are brought together under a composition layer. It provides an end-to-end runtime environment where microservices can collaborate to deliver sophisticated, composite business capabilities.

Q14: What is the Chain of Responsibility pattern in microservices?

A14: The Chain of Responsibility pattern decouples the sender and receiver of a request based on the type of the request. This request is passed through a chain of objects until it is handled. In the context of microservices, this pattern can be used for building pipelines and managing workflows among services.

Q15: What is the Asynchronous Messaging pattern?

A15: The Asynchronous Messaging pattern is a communication pattern in which the sender and receiver of messages do not need to interact with the messaging system at the same time. This pattern is often used in microservices architectures to ensure loose coupling, maintain data consistency, and handle communication between services.

Q16: What is the Bulkhead pattern in microservices?

A16: The Bulkhead pattern is a design strategy where elements are isolated into pools (like compartments or "bulkheads" in a ship) so that if one fails, the others will continue to function. In microservices, this pattern can prevent failures in one service from cascading to others.

Q17: What is the Anti-Corruption Layer (ACL) pattern?

A17: The Anti-Corruption Layer (ACL) pattern is used to encapsulate and isolate the interaction between different subsystems, particularly when one is transitioning from a monolithic design to a microservices architecture. The ACL translates requests from the new system into a format that can be understood by the legacy system and vice versa, effectively "isolating" any corruption that might be introduced by the legacy system.

Q18: What is the Retry pattern?

A18: The Retry pattern is a fundamental pattern used in distributed systems like microservices to handle transient failures when trying to connect to a service or network resource. By using this pattern, the application will automatically retry the operation in expectation that the failure was transient, and the next attempt will succeed.

Q19: What is the Health Check pattern?

A19: The Health Check pattern is a preventive measure that allows services to report their status, indicating whether they're functioning correctly or not. A health check API endpoint might return basic information about the system's status, or it might perform more comprehensive checks before reporting that the service is up.

Q20: What is the Decoupling Middleware pattern?

A20: The Decoupling Middleware pattern involves using messaging platforms and event-driven architectures to decouple microservices, which can communicate asynchronously through events or messages. This pattern helps to ensure that services are loosely coupled, enabling them to be developed, deployed, and scaled independently.

Q21: What is the Observability and Monitoring pattern?

A21: Observability and Monitoring is not a single pattern but a set of practices and tools used to understand the state and performance of a microservices-based system. This may include logging, tracing, metrics collection, and visualization, alerting, and anomaly detection, among others.

Q22: What is the Sharding pattern in microservices?

A22: The Sharding pattern, also known as horizontal partitioning, involves splitting the data store across multiple databases based on a shard key. Each shard runs on a separate machine or separate cluster, thus allowing the data to be spread across many servers, increasing the overall read and write capacity of the system.

Q23: What is the Event Sourcing pattern?

A23: Event Sourcing is a pattern that derives the current state of an application from a sequence of events. Instead of modifying the state directly, state changes are logged as events, which can be replayed to reconstruct past states. This can be beneficial for debugging, auditing, and in systems where maintaining history is critical.

Q24: What is the Throttling pattern?

A24: The Throttling pattern is a way to control the consumption rate of a service to prevent it from being overwhelmed by requests. This can be particularly useful in a microservice architecture where certain services might be more resource-intensive than others. By implementing a throttling mechanism, the system can better handle peaks in demand.

Q25: What is the Blue-Green Deployment pattern?

A25: Blue-Green Deployment is a release management strategy aimed at reducing downtime and risk by running two identical production environments, Blue and Green. At any given time, only one of them is live. For instance, the Blue environment is live and when you want to deploy a new version of your application, you do that in the Green environment. Once you have tested it and ready to go live, you switch the router so all incoming requests now go to the Green environment.

Q26: What is the Ambassador pattern?

A26: The Ambassador pattern is a helper service that sends network requests on behalf of a consumer service or application. This pattern can be used to offload common client connectivity tasks such as monitoring, logging, routing, and security (like TLS termination) in the context of outbound communication.

Q27: What is the Choreography pattern in event-driven microservices?

A27: In event-driven microservices, the Choreography pattern is an approach where each service produces, listens for, and reacts to events independently, resulting in a system that operates like a sequence of dancers where each one knows what to do upon hearing a specific piece of music. This contrasts with the Orchestration pattern, where a centralized director tells each service what to do and when.

Q28: What is the Canary Deployment pattern?

A28: Canary Deployment is a pattern where a new version of a microservice is gradually rolled out to a small subset of users to test its performance and functionality in the production environment before a full rollout. It's named after the "canary in the coal mine" concept, as these users effectively serve as the "canary," providing an early warning of any issues with the new version.

Q29: What is the Orchestration pattern in microservices?

A29: The Orchestration pattern is a way of coordinating and managing multiple services to accomplish a specific application-level function. An orchestrator service takes responsibility for conducting other services to fulfill a business process, which involves making decisions, sequencing service interactions, and aggregating results.

Q30: What is the Cache-Aside pattern?

A30: The Cache-Aside pattern in microservices involves loading data into the cache on demand when a request is made. If the requested data is not in the cache, it's retrieved from the data store and added to the cache. Subsequent requests for the same data can then be served from the cache to improve performance.