Why load balancing matters in AWS - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a load balancer that distributes traffic evenly.

AWS

LoadBalancerName: "MyLoadBalancer"
Listeners:
  - Protocol: HTTP
    LoadBalancerPort: 80
    InstancePort: [1]

Drag options to blanks, or click blank then click option'

A80

B22

C443

D8080

Attempts:

3 left

💡 Hint

Common Mistakes

Using port 22 which is for SSH, not HTTP.

The load balancer listens on port 80 to distribute HTTP traffic to instances on the same port.

2fill in blank

medium

Complete the code to specify the health check path for the load balancer.

AWS

HealthCheck:
  Target: "HTTP:[1]/health"
  Interval: 30
  Timeout: 5

Drag options to blanks, or click blank then click option'

A22

B80

C443

D8080

Attempts:

3 left

💡 Hint

Common Mistakes

Using port 22 which is for SSH, not HTTP.

The health check uses HTTP on port 80 to verify instance health.

3fill in blank

hard

Fix the error in the listener configuration to allow HTTPS traffic.

AWS

Listeners:
  - Protocol: [1]
    LoadBalancerPort: 443
    InstancePort: 443

Drag options to blanks, or click blank then click option'

AHTTP

BFTP

CHTTPS

DSSH

Attempts:

3 left

💡 Hint

Common Mistakes

Using HTTP on port 443 causes errors.

HTTPS protocol is required for secure traffic on port 443.

4fill in blank

hard

Fill both blanks to configure a load balancer with cross-zone load balancing enabled and a security group.

AWS

LoadBalancerAttributes:
  CrossZoneLoadBalancing: [1]
SecurityGroups:
  - [2]

Drag options to blanks, or click blank then click option'

Atrue

Bfalse

Csg-123abc45

Dsg-678def90

Attempts:

3 left

💡 Hint

Common Mistakes

Setting cross-zone load balancing to false reduces efficiency.

Cross-zone load balancing should be enabled with 'true'. Security group IDs like 'sg-123abc45' control access.

5fill in blank

hard

Fill all three blanks to define a target group with a health check path and protocol.

AWS

TargetGroup:
  Name: "MyTargetGroup"
  Protocol: [1]
  Port: [2]
  HealthCheckPath: "[3]"

Drag options to blanks, or click blank then click option'

AHTTP

B80

C/healthcheck

DTCP

Attempts:

3 left

💡 Hint

Common Mistakes

Using TCP protocol without a health check path causes monitoring issues.

The target group uses HTTP on port 80 with a health check path '/healthcheck' to monitor instance health.

Practice

1. What is the main purpose of a load balancer in AWS?

easy

A. To create backups of servers automatically

B. To store user data securely

C. To distribute incoming traffic evenly across multiple servers

D. To monitor server CPU usage only

Solution

1. Step 1: Understand load balancer role

   A load balancer shares user traffic across servers to keep apps fast and reliable.

2. Step 2: Identify main function

   Its main job is to distribute incoming traffic evenly to avoid overloading one server.

3. Final Answer:

   To distribute incoming traffic evenly across multiple servers -> Option C

4. Quick Check:

   Load balancer = distribute traffic [OK]

Hint: Load balancer spreads traffic to avoid overload [OK]

Common Mistakes:

• Confusing load balancer with data storage
• Thinking it only monitors CPU
• Assuming it creates backups

2. Which AWS service is used to create a load balancer?

easy

A. Amazon S3

B. Elastic Load Balancing (ELB)

C. Amazon RDS

D. AWS Lambda

Solution

1. Step 1: Identify AWS services

   Amazon S3 stores files, RDS manages databases, Lambda runs code, ELB manages load balancing.

2. Step 2: Match service to load balancing

   Elastic Load Balancing (ELB) is the AWS service designed to create load balancers.

3. Final Answer:

   Elastic Load Balancing (ELB) -> Option B

4. Quick Check:

   Load balancer service = ELB [OK]

Hint: ELB is the AWS load balancer service name [OK]

Common Mistakes:

• Choosing storage or compute services instead of ELB
• Confusing Lambda with load balancing
• Selecting database services

3. Given this AWS setup code snippet, what does the load balancer do?

LoadBalancer -> TargetGroup -> EC2 Instances
Listener listens on port 80 and forwards to TargetGroup

medium

A. It forwards traffic on port 80 to all EC2 instances evenly

B. It blocks traffic on port 80

C. It stores data from EC2 instances

D. It only forwards traffic to one EC2 instance

Solution

1. Step 1: Understand listener role

   The listener listens on port 80 and forwards requests to the target group.

2. Step 2: Understand target group role

   The target group contains multiple EC2 instances and the load balancer distributes traffic evenly among them.

3. Final Answer:

   It forwards traffic on port 80 to all EC2 instances evenly -> Option A

4. Quick Check:

   Listener + TargetGroup = distribute traffic [OK]

Hint: Listener forwards traffic evenly to all targets [OK]

Common Mistakes:

• Thinking it blocks traffic
• Assuming it stores data
• Believing it sends traffic to only one instance

4. You set up a load balancer but all traffic goes to a single server. What is the likely mistake?

medium

A. Security group blocks all traffic

B. Listener is set to forward on wrong port

C. Load balancer is not created

D. Target group has only one instance registered

Solution

1. Step 1: Check target group configuration

   If only one instance is registered in the target group, all traffic goes to that instance.

2. Step 2: Verify listener and load balancer existence

   Listener forwarding on wrong port or missing load balancer would cause no traffic or errors, not single server traffic.

3. Final Answer:

   Target group has only one instance registered -> Option D

4. Quick Check:

   Single server traffic = one target instance [OK]

Hint: Check target group instance count first [OK]

Common Mistakes:

• Assuming listener port causes single server traffic
• Thinking load balancer absence sends traffic
• Blaming security group for traffic routing

5. You want to handle sudden traffic spikes without slowing your app. Which load balancing setup helps best?

hard

A. Use a load balancer with multiple target groups and auto-scaling EC2 instances

B. Use a single EC2 instance behind a load balancer

C. Use only one target group with fixed number of instances

D. Disable load balancer and rely on DNS round robin

Solution

1. Step 1: Understand traffic spike handling

   Handling spikes requires scaling resources automatically to meet demand.

2. Step 2: Match setup to scaling needs

   Using a load balancer with multiple target groups and auto-scaling EC2 instances allows dynamic resource adjustment and balanced traffic.

3. Final Answer:

   Use a load balancer with multiple target groups and auto-scaling EC2 instances -> Option A

4. Quick Check:

   Auto-scaling + load balancer = handle spikes [OK]

Hint: Combine load balancer with auto-scaling for spikes [OK]

Common Mistakes:

• Relying on single instance for heavy traffic
• Using fixed instances without scaling
• Disabling load balancer reduces reliability