Liveness and readiness probes in Microservices - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a liveness probe in microservices?

A liveness probe checks if a service is alive and running. If it fails, the system restarts the service to fix it.

beginner

What does a readiness probe do?

A readiness probe checks if a service is ready to accept traffic. If it fails, the service is removed from load balancing until ready.

intermediate

Why use both liveness and readiness probes together?

Using both helps keep services healthy and only sends traffic to services that are ready, improving reliability and user experience.

beginner

Give a simple example of a liveness probe check.

A liveness probe might send an HTTP GET request to "/healthz" endpoint. If it returns 200 OK, the service is alive.

intermediate

What happens if a readiness probe fails continuously?

The service stops receiving new requests but keeps running. This prevents sending traffic to a service that can't handle it yet.

What is the main purpose of a liveness probe?

A To balance load between services

B To check if the service is alive and restart if needed

C To monitor network latency

D To check if the service is ready to accept traffic

Liveness probes detect if a service is alive and restart it if it is not responding.

If a readiness probe fails, what happens?

A The service is removed from load balancer and stops receiving traffic

B The service is restarted immediately

C The service shuts down

D Nothing happens

Readiness probe failure means the service is not ready, so it stops receiving new traffic but keeps running.

Which probe helps avoid sending traffic to a service that is not ready?

A Liveness probe

B Load balancer

C Startup probe

D Readiness probe

Readiness probes ensure traffic is only sent to services ready to handle requests.

What is a common method used by liveness probes to check service health?

A Measuring disk space

B Checking CPU usage

C Sending an HTTP GET request to a health endpoint

D Verifying user login

Liveness probes often use HTTP GET requests to a health check endpoint to verify service health.

Why is it important to have both liveness and readiness probes?

A To restart services and manage traffic properly

B To increase CPU usage

C To reduce network bandwidth

D To log user activity

Both probes together help keep services running and only send traffic when services are ready.

Explain the difference between liveness and readiness probes in microservices.

Think about when a service should be restarted versus when it should just stop receiving traffic.

Describe a real-life scenario where readiness probes improve user experience.

Imagine a restaurant kitchen not ready to serve but still open.