Load Balancers (Application, Network, Global) Interview Question Answer

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Professional Load Balancers (Application, Network, Global) FAQ Questions and Answers

Welcome to our comprehensive Trivia Quiz and interview preparation guide. Below you will find a curated list of popular Trivia Questions and Answers specifically for Load Balancers (Application, Network, Global). Whether you are preparing for a technical interview or just testing your knowledge, these FAQ Questions will help you succeed.

What is a load balancer?

A load balancer is a system that distributes incoming network or application traffic across multiple servers to ensure no single server becomes overwhelmed.

What are the main types of load balancers?

The main types are Application Load Balancer (ALB), Network Load Balancer (NLB), and Global Load Balancer.

What is an Application Load Balancer?

An ALB operates at the application layer (Layer 7) and routes traffic based on content such as URL, hostname, or headers.

What is a Network Load Balancer?

A NLB works at the transport layer (Layer 4) and routes traffic based on IP protocol data.

What is a Global Load Balancer?

A Global Load Balancer distributes traffic across servers in multiple geographic regions to improve latency and availability.

Which layer of the OSI model does ALB operate on?

ALB operates on Layer 7 (Application Layer).

Which layer does the NLB operate on?

NLB operates on Layer 4 (Transport Layer).

What is path-based routing in ALB?

It allows routing of requests to different targets based on the URL path of the request.

What is host-based routing in ALB?

Host-based routing forwards requests based on the hostname in the HTTP header.

What is sticky session or session affinity?

It is a feature that binds a user's session to a specific server, maintaining session state.

Does NLB support SSL termination?

No, NLB passes the SSL traffic directly to the target server without termination.

What is SSL termination?

It?s when the load balancer decrypts the SSL traffic before passing it to backend servers.

Which load balancer supports WebSocket?

Application Load Balancer supports WebSocket connections.

What is health checking in load balancers?

Health checks monitor the health of backend instances and route traffic only to healthy ones.

What protocols are supported by ALB?

ALB supports HTTP, HTTPS, and WebSocket.

What protocols are supported by NLB?

NLB supports TCP, TLS, and UDP.

What is cross-zone load balancing?

Cross-zone load balancing distributes traffic evenly across all registered targets in all availability zones.

Is cross-zone load balancing enabled by default in ALB?

Yes, it is enabled by default in ALB.

What are target groups in AWS ALB?

Target groups are used to route requests to one or more registered targets such as EC2 instances or containers.

What is listener in load balancer?

A listener checks for connection requests using the protocol and port you configure.

What are the pricing models for load balancers?

They are usually charged per hour and per GB of data processed.

What is latency-based routing in Global Load Balancer?

It directs traffic to the region with the lowest latency for the client.

Can load balancers auto-scale?

Load balancers themselves don?t auto-scale, but they distribute traffic to auto-scaling backend instances.

What is the benefit of using Global Load Balancer?

It improves performance and reliability by routing users to the nearest healthy region.

What is a backend pool in Azure Load Balancer?

A backend pool is a collection of IP addresses of virtual machines to receive the load-balanced traffic.

What is a rule in Azure Load Balancer?

Rules define how traffic is distributed to backend pool instances.

What are probes in Azure Load Balancer?

Probes are used to determine the health of backend instances.

What is the difference between internal and external load balancer?

Internal load balancer routes traffic within a private network, while external LB handles public-facing traffic.

What is autoscaling and how does it relate to load balancing?

Autoscaling automatically adjusts the number of backend resources based on load; load balancers help manage the distribution.

What is IP affinity?

It binds a user's IP address to a specific backend server to maintain session continuity.

Can a load balancer perform content-based routing?

Yes, especially Application Load Balancers can route based on content like URLs and headers.

What is DNS-based load balancing?

It uses DNS responses to distribute traffic across multiple IP addresses or regions.

How does failover work in Global Load Balancers?

Traffic is redirected to a secondary region or endpoint when the primary becomes unhealthy.

What is weighted round robin?

It distributes traffic based on pre-assigned weights to backend servers.

What is a reverse proxy?

A reverse proxy forwards client requests to backend servers and is commonly used in ALBs.

What are common algorithms used in load balancing?

Round Robin, Least Connections, IP Hash, and Weighted Distribution.

What is a listener rule in ALB?

Listener rules determine how requests are routed to target groups based on conditions like path or host.

Can NLB handle sudden traffic spikes?

Yes, NLB is designed to handle millions of requests per second with ultra-low latency.

What is the benefit of using NLB over ALB?

NLB provides high performance for TCP and UDP traffic and is ideal for real-time applications.

Does ALB support Lambda functions as targets?

Yes, ALB supports AWS Lambda as a target.

How is traffic distributed in a round-robin load balancer?

It distributes traffic equally across all backend servers in a cyclic order.

What is geolocation routing?

Geolocation routing sends user requests to resources based on their geographic location.

What is health probe timeout?

It defines the amount of time to wait for a response before considering the target unhealthy.

What is deregistration delay in load balancers?

It?s the time a target remains registered after being marked unhealthy, to finish processing in-flight requests.

Can multiple listeners be attached to a single ALB?

Yes, multiple listeners with different ports or protocols can be attached to a single ALB.

What is a multi-region load balancer?

It routes traffic across multiple cloud regions for fault tolerance and performance.

Does NLB support static IP addresses?

Yes, NLB supports static IP and Elastic IP addresses.

What is auto-healing in load balancers?

It refers to removing unhealthy instances from the pool and redistributing traffic to healthy ones.

What monitoring tools are available for load balancers?

CloudWatch (AWS), Azure Monitor, and built-in dashboards provide metrics and logs.

What is connection draining?

It allows in-flight requests to complete before terminating the instance or deregistering it from the load balancer.