Health checks configuration in AWS - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the purpose of a health check in AWS?

A health check monitors the status of resources like servers or load balancers to ensure they are working properly. If a resource fails the health check, AWS can stop sending traffic to it.

beginner

Name two types of health checks used in AWS Elastic Load Balancing.

1. HTTP/HTTPS health checks: They send a request to a specific URL path and expect a response.<br>2. TCP health checks: They check if a TCP connection can be established on a port.

intermediate

What does the 'Healthy threshold' setting control in a health check?

It defines how many consecutive successful health checks are needed before considering a resource healthy again.

intermediate

Why is the 'Interval' setting important in health checks?

It sets how often AWS performs the health check. A shorter interval means faster detection of failures but more network traffic.

beginner

What happens if a resource fails the health check 'Unhealthy threshold' times?

AWS marks the resource as unhealthy and stops sending traffic to it until it passes health checks again.

Which AWS service commonly uses health checks to route traffic?

A IAM

B S3 Bucket

C CloudWatch Logs

D Elastic Load Balancer

Elastic Load Balancers use health checks to decide which instances should receive traffic.

What does a TCP health check verify?

A If a TCP connection can be established on a port

B If the DNS resolves correctly

C If the server CPU is under 80%

D If a web page returns status 200

TCP health checks test if a TCP connection can be made to the resource on a specific port.

If the 'Unhealthy threshold' is set to 3, how many failed checks mark a resource unhealthy?

A 1

B 3

C 2

D 4

The resource is marked unhealthy after 3 consecutive failed health checks.

What is a benefit of setting a shorter health check interval?

A Faster failure detection

B Less network traffic

C Longer resource downtime

D Reduced CPU usage

Shorter intervals detect failures faster but increase network traffic.

Which protocol is NOT typically used for AWS health checks?

A HTTP

B TCP

C FTP

D HTTPS

FTP is not used for AWS health checks; common protocols are HTTP, HTTPS, and TCP.

Explain how AWS uses health checks to maintain application availability.

Think about how AWS decides where to send user requests.

Describe the key settings you configure when setting up a health check in AWS.

Consider what AWS needs to know to check if a resource is working.