Microservices Service Discovery and Registry Questions and Answers

Question 1

A team is deploying microservices in a container orchestration environment like Kubernetes. When a client service needs to communicate with a provider service, it sends a request to a stable virtual IP address managed by the platform. The platform then routes this request to a healthy instance of the provider service. Which service discovery pattern does this scenario describe?

Accepted Answer

Server-Side Discovery

Answer

This scenario describes Server-Side Discovery. The client sends a request to a logical endpoint (the Kubernetes Service's stable IP), and the platform's networking layer (acting as a server-side proxy/load balancer) is responsible for discovering a healthy service instance and forwarding the request. The client is completely abstracted from the complexity of looking up individual service instances.

Question 2

What is the primary responsibility of a service registry in a microservices architecture?

Accepted Answer

To maintain a dynamic, up-to-date list of available service instances and their network locations.

Answer

The core function of a service registry is to act as a database or a 'phone book' for services. Its main job is to track which service instances are running and where they can be reached (IP address and port). Routing, circuit breaking, and transaction management are separate concerns handled by other components like load balancers, API gateways, or specific patterns.

Question 3

Which of the following is a key characteristic of the client-side service discovery pattern?

Accepted Answer

The client directly queries the service registry to get a list of service instances.

Answer

In the client-side discovery pattern, the client application is responsible for interacting directly with the service registry. It queries the registry to obtain a list of available provider service instances and then uses a load-balancing algorithm to select one to connect to. This places more logic on the client compared to the server-side pattern.

Question 4

A potential disadvantage of the self-registration pattern is that it:

Accepted Answer

Tightly couples the service code with the service registry.

Answer

In the self-registration pattern, the microservice itself contains the logic to register with and send heartbeats to the service registry. This couples the service's business logic with the specific concerns and client libraries of the service discovery infrastructure, making it harder to change the registry technology later.

Question 5

An organization is building a microservices platform using a tool like Netflix Eureka. Each service instance, upon startup, is responsible for registering its own network location with the registry and sending periodic heartbeats to indicate it is healthy. What is this registration approach called?

Accepted Answer

Self-Registration

Answer

This scenario describes the self-registration pattern. The service instance itself takes on the responsibility of managing its lifecycle within the service registry, including registration on startup and sending renewals. Tools like Netflix Eureka are commonly used to implement this pattern.

Microservices Practice Test

Microservices Practice Test

Microservices Service Discovery and Registry Questions and Answers