Why load balancing matters in AWS - Challenge Your Understanding

Challenge - 5 Problems

🧠 Conceptual

intermediate

Why use load balancing in cloud infrastructure?

Which of the following best explains why load balancing is important in cloud infrastructure?

A It evenly distributes incoming traffic across multiple servers to prevent any single server from becoming overwhelmed.

B It automatically upgrades server hardware without downtime.

C It stores all user data in one place to speed up access times.

D It encrypts all data between servers to improve security.

💡 Hint

Think about how traffic is managed when many users visit a website at the same time.

Load balancing helps by spreading user requests across multiple servers, so no single server gets too busy and slows down or crashes.

❓ service_behavior

intermediate

AWS Elastic Load Balancer behavior under high traffic

What happens when AWS Elastic Load Balancer (ELB) receives more traffic than a single server can handle?

A ELB automatically shuts down the overloaded server.

B ELB queues all requests until the server is free, causing delays.

C ELB routes traffic to multiple healthy instances to share the load and maintain performance.

D ELB rejects new requests until the server recovers.

💡 Hint

Consider how ELB helps keep websites responsive during busy times.

ELB balances traffic by sending requests to multiple servers that are healthy, preventing overload on any one server.

❓ Architecture

advanced

Designing a fault-tolerant web application with load balancing

You want to design a web application that stays available even if one server fails. Which architecture best achieves this?

A Use a load balancer that sends all traffic to one server and switches only if it fails.

B Use a single powerful server with a backup server in the same data center.

C Use multiple servers without a load balancer and let clients choose which to connect to.

D Use a load balancer to distribute traffic across multiple servers in different availability zones.

💡 Hint

Think about spreading risk across locations and servers.

Using a load balancer with servers in different zones ensures traffic is shared and the app stays online if one server or zone fails.

❓ security

advanced

Security benefits of load balancers in cloud environments

Which security feature is commonly provided by cloud load balancers?

A They can terminate SSL/TLS connections to offload encryption work from backend servers.

B They store user passwords securely for authentication.

C They scan all incoming traffic for viruses before forwarding.

D They automatically patch backend servers with security updates.

💡 Hint

Think about how encryption is handled between users and servers.

Load balancers often handle SSL/TLS termination, decrypting traffic so backend servers don’t have to, improving performance and security management.

✅ Best Practice

expert

Choosing the right load balancing algorithm for a global app

You run a global app with users in many countries. Which load balancing method best reduces latency for users?

A Use round-robin to evenly distribute users regardless of location.

B Use geo-based routing to send users to the nearest data center.

C Use least connections to send users to the server with fewest active sessions.

D Use random selection to balance load unpredictably.

💡 Hint

Think about how to make websites load faster for users far apart.

Geo-based routing directs users to the closest data center, reducing delay and improving experience worldwide.

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