Azure Load Balancer (Layer 4) - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

Understanding Azure Load Balancer's Traffic Distribution

Azure Load Balancer operates at Layer 4. Which statement best describes how it distributes incoming traffic?

A It distributes traffic based on IP address and port using a hash-based algorithm without inspecting packet content.

B It inspects HTTP headers to route requests to specific backend servers based on URL paths.

C It uses DNS-based routing to direct traffic to different regions based on user location.

D It terminates SSL connections and forwards decrypted traffic to backend servers.

💡 Hint

Think about what Layer 4 means in the OSI model and what kind of information is available at that layer.

Azure Load Balancer works at Layer 4, which means it routes traffic based on IP address and port without inspecting higher-level data like HTTP headers or URLs.

❓ Architecture

intermediate

Designing a High Availability Setup with Azure Load Balancer

You want to design a highly available web application using Azure Load Balancer. Which architecture best ensures no single point of failure?

A Deploy multiple VMs in a single availability zone behind an Azure Load Balancer.

B Deploy multiple VMs in different regions without Azure Load Balancer.

C Use a single VM with Azure Load Balancer to distribute traffic to itself.

D Deploy multiple VMs across multiple availability zones behind an Azure Load Balancer with health probes.

💡 Hint

Consider how Azure Load Balancer and availability zones work together to avoid downtime.

Deploying VMs across multiple availability zones with health probes ensures that if one zone fails, traffic is routed to healthy VMs in other zones, avoiding single points of failure.

❓ scaling

advanced

Scaling Backend Pool with Azure Load Balancer

Your application experiences sudden traffic spikes. How does Azure Load Balancer handle scaling backend VMs to maintain performance?

A Azure Load Balancer automatically adds new VMs to the backend pool without manual intervention.

B Azure Load Balancer duplicates traffic to all VMs regardless of backend pool membership during spikes.

C You must manually add or remove VMs from the backend pool; Azure Load Balancer distributes traffic only to registered VMs.

D Azure Load Balancer queues excess traffic until backend VMs scale up automatically.

💡 Hint

Think about how Azure Load Balancer knows which VMs to send traffic to and how scaling works in Azure.

Azure Load Balancer distributes traffic only to VMs registered in its backend pool. Scaling VMs requires manual or automated processes outside the load balancer to add or remove VMs from the pool.

❓ tradeoff

advanced

Choosing Between Azure Load Balancer and Application Gateway

You need to decide between Azure Load Balancer (Layer 4) and Azure Application Gateway (Layer 7) for your web app. Which tradeoff is accurate?

A Azure Load Balancer is simpler and faster for TCP/UDP traffic but cannot inspect HTTP content; Application Gateway supports advanced HTTP routing but adds latency.

B Azure Load Balancer automatically scales HTTP routes, while Application Gateway requires manual scaling.

C Azure Load Balancer supports Web Application Firewall (WAF), but Application Gateway does not.

D Azure Load Balancer offers SSL termination and URL-based routing, while Application Gateway only handles TCP traffic.

💡 Hint

Consider the OSI layers each service operates on and their feature sets.

Azure Load Balancer works at Layer 4, handling TCP/UDP traffic quickly without inspecting HTTP details. Application Gateway works at Layer 7, enabling HTTP-specific features like SSL termination and URL routing but with some added latency.

❓ estimation

expert

Estimating Azure Load Balancer Capacity for High Traffic

Your service expects 1 million TCP connections per second. What is the best approach to estimate if Azure Load Balancer can handle this load?

A Assume Azure Load Balancer has unlimited capacity and focus only on backend VM scaling.

B Check Azure Load Balancer's documented maximum throughput and scale backend VMs accordingly, considering health probe overhead.

C Use Azure Load Balancer only for UDP traffic and switch to Application Gateway for TCP connections.

D Distribute traffic evenly by DNS round-robin and avoid using Azure Load Balancer for high connection counts.

💡 Hint

Think about official Azure service limits and how to plan capacity.

Azure Load Balancer has documented limits on throughput and connections per second. Estimating capacity requires consulting these limits and scaling backend resources while considering health probe traffic.