Service discovery concept in Microservices - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

What is the primary role of service discovery in microservices?

In a microservices architecture, what is the main purpose of service discovery?

A To manage user authentication and authorization

B To store user data securely in a database

C To monitor the health of a single service only

D To enable services to find and communicate with each other dynamically without hardcoding addresses

💡 Hint

Think about how services know where to send requests when their locations can change.

Service discovery allows microservices to locate each other dynamically, avoiding hardcoded IPs or ports, which can change due to scaling or failures.

❓ Architecture

intermediate

Which component typically acts as the service registry in service discovery?

In a microservices system, which component is responsible for keeping track of all available service instances?

A Service registry

B API gateway

C Database

D Load balancer

💡 Hint

This component holds the list of active services and their locations.

The service registry maintains a dynamic list of service instances and their network locations, enabling service discovery.

❓ scaling

advanced

How does service discovery help when scaling microservices horizontally?

When multiple instances of a microservice are added to handle more load, how does service discovery assist?

A It requires manual configuration of each new instance's address

B It duplicates the database to match the number of instances

C It automatically updates the registry with new instances so clients can find them without manual changes

D It disables older instances to avoid conflicts

💡 Hint

Think about how new service instances become discoverable without manual intervention.

Service discovery updates the registry dynamically as new instances start or stop, allowing clients to find all available instances automatically.

❓ tradeoff

advanced

What is a tradeoff of using client-side service discovery compared to server-side?

Client-side and server-side service discovery are two common patterns. What is a key tradeoff when using client-side discovery?

A Clients handle more complexity but reduce load on central components

B Clients have less control over routing decisions

C It requires no service registry at all

D It eliminates the need for load balancing

💡 Hint

Consider who manages the discovery logic and the impact on system components.

Client-side discovery pushes the responsibility to clients, increasing their complexity but reducing dependency on central servers, which can improve scalability.

❓ estimation

expert

Estimate the number of service registry updates per minute in a system with 100 microservice instances, each registering every 30 seconds.

Assuming each of the 100 microservice instances sends a heartbeat or registration update every 30 seconds, how many updates does the service registry receive per minute?

A 100 updates per minute

B 200 updates per minute

C 50 updates per minute

D 300 updates per minute

💡 Hint

Calculate how many updates each instance sends per minute and multiply by the number of instances.

Each instance sends 2 updates per minute (60/30). With 100 instances, total updates = 100 * 2 = 200 per minute.