Elastic IPs and Elastic Load Balancers Questions and Answers for Viva

Answer-1: An Elastic IP is a static, public IPv4 address designed for dynamic cloud computing, allowing you to remap the address to any instance in your account.

Answer-2: An ELB automatically distributes incoming application traffic across multiple targets, such as EC2 instances, in multiple availability zones.

Answer-3: AWS provides three types: Application Load Balancer (ALB), Network Load Balancer (NLB), and Gateway Load Balancer (GLB).

Answer-4: No, Elastic IPs can only be associated with instances or network interfaces, not with Application or Network Load Balancers directly.

Answer-5: Elastic IPs are used for maintaining a consistent public IP address for services that require it even when the underlying instance changes.

Answer-6: A standard public IP changes when you stop/start an EC2 instance; an Elastic IP remains static until released.

Answer-7: The first Elastic IP is free if it's associated with a running instance; otherwise, there's a small hourly charge.

Answer-8: It operates at the HTTP/HTTPS layer and routes requests based on content, using rules and listener conditions.

Answer-9: A listener checks for connection requests from clients and forwards them to one or more target groups based on configured rules.

Answer-10: A target group is used to route requests to one or more registered targets, such as EC2 instances or IP addresses.

Answer-11: Yes, if the instance has multiple network interfaces, you can attach multiple Elastic IPs.

Answer-12: ELBs provide automatic scaling, high availability, and fault tolerance for applications.

Answer-13: By default, AWS allows up to 5 Elastic IPs per region, which can be increased upon request.

Answer-14: It allows load balancers to distribute incoming requests across instances in multiple availability zones.

Answer-15: Yes, you can register on-premise servers as targets in a target group by specifying IP addresses.

Answer-16: ELBs periodically ping registered targets to ensure they are healthy and route traffic only to healthy targets.

Answer-17: Sticky sessions (session affinity) enable the load balancer to bind a user?s session to a specific target.

Answer-18: ELB supports common ports like 80

Answer-19: NLB operates at the TCP layer and is optimized for performance; ALB operates at the HTTP layer and supports routing rules.

Answer-20: Yes, you can associate static IP addresses (Elastic IPs) with NLBs.

Answer-21: By distributing traffic across multiple availability zones and using health checks to route to healthy instances.

Answer-22: No, Auto Scaling handles IP assignments dynamically; however, you can use a NAT gateway or load balancer.

Answer-23: It is the time the load balancer waits before deregistering a target during a scale-in event.

Answer-24: ELB can decrypt SSL traffic before forwarding it to instances, reducing the load on backend servers.

Answer-25: Yes, multiple ELBs can be configured in the same VPC for different applications.

Answer-26: Elastic IPs are limited per region and are not automatically scalable or load balanced.

Answer-27: No, for scalability and fault tolerance, it's better to use a Load Balancer instead.

Answer-28: It is a type of ELB that enables deployment, scaling, and management of third-party virtual appliances.

Answer-29: Also known as deregistration delay, it ensures in-flight requests are completed before the instance is deregistered.

Answer-30: No, Elastic IPs are region-specific and cannot be transferred across regions.

Answer-31: The Elastic IP remains allocated and incurs charges unless reassigned or released.

Answer-32: No, Elastic IPs are tied to EC2 and ENIs, not serverless functions like Lambda.

Answer-33: Idle timeout is the time ELB waits before closing an idle connection; default is 60 seconds.

Answer-34: It integrates with Auto Scaling groups and automatically adjusts traffic distribution based on scaling events.

Answer-35: Access logs capture detailed information about client requests sent to the load balancer, useful for auditing and debugging.

Answer-36: Yes, you can release Elastic IPs when they are no longer needed to avoid charges.

Answer-37: Using AWS CloudWatch, you can track metrics like request count, latency, and backend connection errors.

Answer-38: Up to 1000 targets can be registered in a target group by default.

Answer-39: It routes traffic based on the host field in the HTTP header, useful for multiple domains.

Answer-40: It routes traffic to different targets based on the request path (e.g., `/api`, `/images`).

Answer-41: AWS provides a DNS name (e.g., `myelb-123456.us-west-2.elb.amazonaws.com`) which you can use instead of an IP.

Answer-42: No, Elastic IPs are public IPs and cannot be used with private subnets unless via NAT gateways.

Answer-43: You define AWS ELB or ALB resources in Terraform configuration and apply them using `terraform apply`.

Answer-44: Yes, especially with ECS or EKS, where services are registered as targets with ALBs or NLBs.

Answer-45: Security groups control the inbound and outbound traffic to and from the load balancer.

Answer-46: Yes, by switching traffic between different target groups or listener rules.

Answer-47: ELB integrates with Route 53 for DNS-based health checks and automatic failover.

Answer-48: A single NAT Gateway can be associated with one Elastic IP.

Answer-49: Yes, you can disassociate and reassign an Elastic IP to a different instance or network interface.

Answer-50: Because their static nature doesn?t scale with dynamically created and destroyed instances; ELB is more suited.