Health check endpoints in HLD - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a health check endpoint in a system?

A health check endpoint is a special URL or API in a system that reports if the system or service is working properly. It helps monitor system health by returning status like 'healthy' or 'unhealthy'.

intermediate

Why are health check endpoints important in distributed systems?

They help detect failures early, enable automatic recovery or load balancing, and improve system reliability by providing real-time status to monitoring tools.

beginner

Name two common types of health checks used in endpoints.

1. Liveness check: verifies if the service is running and not stuck.<br>2. Readiness check: verifies if the service is ready to handle requests.

intermediate

What should a health check endpoint avoid doing to keep the system efficient?

It should avoid heavy computations, long database queries, or complex logic. It should respond quickly with simple checks to prevent adding load or delays.

advanced

How can health check endpoints help with auto-scaling in cloud environments?

Auto-scaling systems use health check results to decide when to add or remove instances. If many instances report unhealthy, new ones can be started to maintain performance.

What does a readiness health check indicate?

A If the service is ready to accept traffic

B If the network is slow

C If the database is down

D If the service is running and not stuck

Readiness checks confirm if the service is ready to handle requests, unlike liveness checks which verify if the service is running.

Which of the following is NOT a good practice for health check endpoints?

A Perform heavy database queries

B Respond quickly with simple status

C Return HTTP 200 when healthy

D Separate liveness and readiness checks

Health checks should avoid heavy operations to keep the system responsive and avoid extra load.

What HTTP status code usually indicates a healthy service in a health check endpoint?

A 404

B 500

C 200

D 302

HTTP 200 means OK, indicating the service is healthy.

How do health check endpoints assist load balancers?

A By encrypting traffic

B By providing service health status to route traffic

C By storing user sessions

D By caching static files

Load balancers use health check results to send traffic only to healthy instances.

Which type of health check would detect if a service is stuck in an infinite loop?

A Security check

B Readiness check

C Performance check

D Liveness check

Liveness checks detect if the service is alive and not stuck or crashed.

Explain the difference between liveness and readiness health check endpoints and why both are useful.

Think about service running status versus ability to serve requests.

Describe best practices for designing efficient health check endpoints in a scalable system.

Focus on performance and clarity of health status.