ALB vs NLB decision in AWS - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to select the load balancer type for HTTP traffic.

AWS

load_balancer = aws_lb("myLB", load_balancer_type=[1])

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

A"network"

B"gateway"

C"classic"

D"application"

Attempts:

3 left

💡 Hint

Common Mistakes

Choosing 'network' which is for TCP/UDP traffic, not HTTP.

Using 'classic' which is older and less flexible.

For HTTP traffic, an Application Load Balancer (ALB) is the best choice because it works at the application layer.

2fill in blank

medium

Complete the code to select the load balancer type for TCP traffic with high performance.

AWS

load_balancer = aws_lb("myLB", load_balancer_type=[1])

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

A"application"

B"network"

C"classic"

D"gateway"

Attempts:

3 left

💡 Hint

Common Mistakes

Choosing 'application' which is for HTTP/HTTPS, not raw TCP.

Using 'classic' which is outdated.

Network Load Balancer (NLB) is designed for TCP traffic and provides high performance and low latency.

3fill in blank

hard

Fix the error in the code to create a listener for an ALB on port 80.

AWS

listener = aws_lb_listener("myListener", load_balancer_arn=alb.arn, port=[1], protocol="HTTP")

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

A80

B22

C443

D8080

Attempts:

3 left

💡 Hint

Common Mistakes

Using port 443 which is for HTTPS.

Using port 22 which is for SSH.

Port 80 is the standard port for HTTP traffic on an Application Load Balancer.

4fill in blank

hard

Fill both blanks to configure a health check for an NLB on TCP port 443.

AWS

health_check = aws_lb_target_group_health_check(protocol=[1], port=[2])

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

A"TCP"

B"HTTP"

C"443"

D"80"

Attempts:

3 left

💡 Hint

Common Mistakes

Using HTTP protocol for NLB health checks.

Using port 80 instead of 443.

NLB health checks use TCP protocol on the port where the service listens, here port 443.

5fill in blank

hard

Fill all three blanks to create an ALB listener rule that forwards requests with path '/app' to a target group.

AWS

rule = aws_lb_listener_rule("myRule", listener_arn=listener.arn, priority=10, action=[1], condition=[2], target_group_arn=[3])

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

A{"type": "forward"}

B{"field": "path-pattern", "values": ["/app"]}

Ctarget_group.arn

D{"type": "redirect"}

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'redirect' action instead of 'forward'.

Using wrong path pattern in condition.

Not specifying the target group ARN.

The action must be 'forward' to send traffic to the target group. The condition matches the path '/app'. The target group ARN specifies where to send the traffic.

Practice

1. Which AWS load balancer should you choose if you want to route HTTP requests based on URL paths?

easy

A. Gateway Load Balancer

B. Network Load Balancer (NLB)

C. Classic Load Balancer

D. Application Load Balancer (ALB)

Solution

1. Step 1: Understand ALB routing capabilities

   ALB can route HTTP/HTTPS traffic based on content like URL paths or host headers.

2. Step 2: Compare with NLB capabilities

   NLB routes at the network level and does not inspect HTTP content for routing.

3. Final Answer:

   Application Load Balancer (ALB) -> Option D

4. Quick Check:

   Content-based routing = ALB [OK]

Hint: Use ALB for HTTP content routing, not NLB [OK]

Common Mistakes:

• Choosing NLB for HTTP content routing
• Confusing Classic Load Balancer with ALB
• Assuming NLB can inspect HTTP headers

2. Which protocol is primarily supported by Network Load Balancer (NLB) for fast, low-latency traffic?

easy

A. TCP/UDP

B. FTP

C. HTTP/HTTPS

D. SMTP

Solution

1. Step 1: Identify NLB protocol support

   NLB is designed to handle TCP and UDP traffic for fast, low-latency connections.

2. Step 2: Exclude HTTP/HTTPS protocols

   HTTP/HTTPS are application layer protocols handled by ALB, not NLB.

3. Final Answer:

   TCP/UDP -> Option A

4. Quick Check:

   NLB = TCP/UDP traffic [OK]

Hint: NLB handles TCP/UDP, ALB handles HTTP/HTTPS [OK]

Common Mistakes:

• Selecting HTTP/HTTPS for NLB
• Confusing FTP or SMTP as NLB protocols
• Assuming NLB supports application layer protocols

3. You have a web application that requires routing requests based on hostnames and needs SSL termination. Which load balancer will correctly handle this?

medium

A. Network Load Balancer (NLB)

B. Gateway Load Balancer

C. Application Load Balancer (ALB)

D. Classic Load Balancer

Solution

1. Step 1: Check hostname-based routing support

   ALB supports routing based on hostnames, which is needed here.

2. Step 2: Confirm SSL termination capability

   ALB can terminate SSL connections, simplifying certificate management.

3. Final Answer:

   Application Load Balancer (ALB) -> Option C

4. Quick Check:

   Hostname routing + SSL termination = ALB [OK]

Hint: SSL termination and hostname routing need ALB [OK]

Common Mistakes:

• Choosing NLB which lacks hostname routing
• Assuming Classic Load Balancer supports advanced routing
• Confusing Gateway Load Balancer with ALB

4. A developer configured a Network Load Balancer to route HTTP traffic and expects it to inspect URL paths for routing. Why is this setup incorrect?

medium

A. NLB does not support TCP traffic

B. NLB cannot inspect HTTP content for routing decisions

C. NLB requires SSL certificates for HTTP routing

D. NLB only supports routing based on IP addresses

Solution

1. Step 1: Understand NLB routing capabilities

   NLB operates at the network layer and cannot inspect HTTP content like URL paths.

2. Step 2: Identify why HTTP content inspection fails

   Routing based on URL paths requires application layer inspection, which only ALB supports.

3. Final Answer:

   NLB cannot inspect HTTP content for routing decisions -> Option B

4. Quick Check:

   NLB lacks HTTP content inspection [OK]

Hint: NLB works at network layer, no HTTP content routing [OK]

Common Mistakes:

• Thinking NLB supports HTTP path routing
• Confusing TCP support with HTTP inspection
• Assuming SSL certs fix routing issues

5. You need to design a system that handles millions of TCP connections with very low latency and also routes HTTP requests based on URL paths. What is the best load balancer setup?

hard

A. Use NLB for TCP connections and ALB for HTTP routing

B. Use only an Application Load Balancer (ALB) for all traffic

C. Use only a Network Load Balancer (NLB) for all traffic

D. Use Classic Load Balancer for both TCP and HTTP traffic

Solution

1. Step 1: Identify requirements for TCP and HTTP traffic

   Millions of TCP connections need low latency, best handled by NLB. HTTP routing by URL paths requires ALB.

2. Step 2: Combine load balancers for best performance

   Use NLB for TCP traffic and ALB for HTTP traffic to meet both needs efficiently.

3. Final Answer:

   Use NLB for TCP connections and ALB for HTTP routing -> Option A

4. Quick Check:

   TCP low latency + HTTP routing = NLB + ALB [OK]

Hint: Combine NLB for TCP and ALB for HTTP routing [OK]

Common Mistakes:

• Using only ALB for TCP traffic causing latency
• Using only NLB missing HTTP routing features
• Choosing Classic Load Balancer for modern needs