Target groups concept in AWS - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

Understanding Target Group Health Checks

What happens when a target in an AWS target group fails its health check?

A The load balancer stops sending traffic to that target until it passes health checks again.

B The target is permanently removed from the target group and must be re-registered manually.

C The load balancer redirects traffic to the failing target to test recovery.

D The target group automatically scales up to replace the failing target.

💡 Hint

Think about how a load balancer keeps your app healthy by avoiding bad servers.

When a target fails health checks, the load balancer temporarily stops sending traffic to it until it becomes healthy again. It does not remove or replace the target automatically.

❓ Architecture

intermediate

Target Group and Load Balancer Association

Which statement correctly describes how target groups are used with an Application Load Balancer (ALB)?

A Target groups are used only for Network Load Balancers, not ALBs.

B Each target group can only be associated with one ALB at a time.

C An ALB routes incoming traffic to one or more target groups based on listener rules.

D An ALB sends traffic directly to EC2 instances without using target groups.

💡 Hint

Consider how ALB directs traffic based on rules and groups of servers.

Application Load Balancers use listener rules to route traffic to one or more target groups. Target groups contain the registered targets like EC2 instances or IP addresses.

❓ Configuration

advanced

Target Group Health Check Configuration Impact

Given this target group health check configuration:

Health check path: /status
Healthy threshold: 3
Unhealthy threshold: 2
Interval: 10 seconds
Timeout: 5 seconds

What is the minimum time before a target is marked unhealthy after it starts failing health checks?

A 20 seconds

B 10 seconds

C 15 seconds

D 30 seconds

💡 Hint

Calculate using the unhealthy threshold and interval values.

The target must fail 2 consecutive health checks (unhealthy threshold) with checks every 10 seconds (interval). So, 2 x 10 = 20 seconds minimum before marked unhealthy.

❓ security

advanced

Security Group Rules for Target Groups

You have an ALB and a target group with EC2 instances. Which security group rule is necessary for the EC2 instances to receive traffic from the ALB?

A Allow inbound traffic from anywhere on all ports.

B Allow inbound traffic on the target port from the ALB's security group.

C Allow outbound traffic to the ALB's IP addresses.

D Allow inbound traffic only from the internet gateway.

💡 Hint

Think about how security groups reference each other for controlled access.

The EC2 instances must allow inbound traffic on the port used by the target group from the ALB's security group to receive traffic securely.

❓ service_behavior

expert

Target Group Deregistration Delay Effect

An EC2 instance is deregistered from a target group with a deregistration delay of 300 seconds. What happens to in-flight requests during this delay?

A The load balancer sends requests to the instance only if it passes health checks during the delay.

B The load balancer immediately stops sending requests, and in-flight requests are terminated.

C The instance is removed instantly, and traffic is routed to other targets without delay.

D The load balancer stops sending new requests to the instance but allows in-flight requests to complete during the delay.

💡 Hint

Consider how deregistration delay helps graceful shutdown.

Deregistration delay allows the load balancer to stop sending new requests but keeps the instance available to complete existing requests during the delay period.