Application Load Balancer (ALB) in AWS - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

How does an Application Load Balancer route traffic?

Imagine you have a web app behind an Application Load Balancer (ALB). How does the ALB decide which server to send a user's request to?

A It always sends all requests to the first server in the list.

B It sends requests randomly to any server without checking health.

C It routes requests based on the content of the request, like URL path or host header.

D It sends requests only to servers that are offline to balance load.

💡 Hint

Think about how ALB can inspect the request details before forwarding.

ALB can look at request details such as URL path or host header to route traffic to different target groups. This allows smart routing based on content.

❓ Architecture

intermediate

Which component is NOT part of an ALB architecture?

In the architecture of an Application Load Balancer, which of these components is NOT involved?

A Listeners that check incoming requests on specific ports.

B Target groups that contain registered servers or containers.

C Auto Scaling groups that automatically add or remove servers.

D DNS servers that resolve domain names to IP addresses.

💡 Hint

Consider which components ALB directly manages versus external services.

DNS servers are external to ALB. ALB uses listeners, target groups, and often works with Auto Scaling groups but does not manage DNS resolution itself.

❓ scaling

advanced

How does ALB handle sudden traffic spikes to maintain performance?

Your web app behind an ALB suddenly gets a huge spike in traffic. How does ALB help maintain performance?

A ALB distributes requests evenly across healthy targets and supports auto scaling integration.

B ALB automatically adds more servers to the target group to handle load.

C ALB queues incoming requests indefinitely until servers are free.

D ALB rejects all new requests until traffic decreases.

💡 Hint

Think about how ALB works with other AWS services to handle load.

ALB balances requests across healthy targets and integrates with Auto Scaling to add or remove servers based on demand, helping maintain performance during spikes.

❓ tradeoff

advanced

What is a tradeoff when using ALB with sticky sessions enabled?

Sticky sessions (session affinity) keep a user's requests on the same server. What is a downside of enabling sticky sessions on ALB?

A It prevents the ALB from checking server health.

B It can cause uneven load because some servers get more requests than others.

C It disables SSL encryption on the ALB.

D It improves load distribution evenly across all servers.

💡 Hint

Consider how sticking users to one server affects load balance.

Sticky sessions can cause some servers to receive more requests than others, leading to uneven load and potential performance issues.

❓ estimation

expert

Estimate the number of concurrent connections ALB can handle for a high-traffic app.

You plan to deploy an ALB for a high-traffic app expecting 100,000 concurrent users. What is a reasonable estimate of ALB's concurrent connection capacity per load balancer?

A About 100,000 concurrent connections per ALB.

B About 1,000,000 concurrent connections per ALB.

C About 10,000 concurrent connections per ALB.

D ALB has no limit on concurrent connections.

💡 Hint

Think about AWS ALB documented limits and typical usage.

AWS ALB supports around 100,000 concurrent connections per load balancer by default, which can be increased by request but is a practical baseline.