What is an elastic load balancer in AWS?

Elastic Load Balancer is an Amazon Application for load balancing service for cloud deployments. This service is good at distributing the application traffic automatically and scales the resources to meet the traffic demands. This service helps IT teams to adjust the capacity according to the network and incoming application traffic. To maintain consistent application performance, users enable the elastic load balancer, within a single availability zone (or) across the multiple availability zones to maintain the consistent application performance. Internally this Elastic load balancer divides the amount of work that the computer does into several tasks to get the task served shortly.

Due to elastic, it is usually implemented as a software load balancer. Due to its elasticity in nature, the system check for the application servers, health status and routes the traffic appropriately to the available servers to manage the failover of high available targets and automatically spins up the needed capacity.

Once the load balancer receives the request from the end-users to access the applications, it routes the traffic based on target instance health. It continuously monitors the health status and the user request to the healthy instances.  While checking, in case of any unhealthy in cases of any unhealthy instance found, the load balancer automatically routes the traffic to other healthy available targets.  

With the elastic load capability, users configure the protocol and port of the listener, a process will identify the connection request between the clients and the load balancer, as well as the load balancer and the instance targets. The listeners present here follow certain policies and the predefined rules to identify the traffic between the client and backend instances.

Elastic Load Balancer automatically distributes the incoming application traffic across multiple targets such as IP Addresses, Amazon Ec2 Instances, containers, Lambda functions as well as virtual appliances. 

Are you new to the concept of AWS, If so check out our article at What is AWS?

What are the different types of Application Load Balancers?

Elastic Load balancers offer 4 types of load balancers, to make the application fault-tolerant. The different types of load balancers are as follows:

 Application Load Balancer:                                                                                                                        

This kind of load balancer operates at the request layer (layer 7) to route the traffic to the target based on the content of the request. This kind of load balancer is ideal for HTTP as well as HTTPS traffic to provide advanced routing techniques, that target the delivery of modern application architectures that include microservices and container-based applications.  This kind of load balancer improves the security of the application, by ensuring the latest SSL/ TLS ciphers and protocols at all the times

Network Load Balancer:

This load balancer kind operates at the connection level (layer 4) in routing the connection to targets within Amazon VPC, based on the IP protocol data. This is ideal for the load balancing of both  TCP and UDP traffic. This Network load balancer is capable of handling millions of requests per second while maintaining ultra-low latencies. This load balancer kind is good at handling sudden and volatile traffic patterns with a single static IP address per availability zone.  Besides, it is integrated with various AWS services like Amazon EC2 Container Service, Auto Scaling, AWS Certification Manager (ACM), and Amazon Cloud Formation

Do you want to get a practical explanation of this balancer? If So, visit AWS Online Training

Gateway Load Balancer:

Gateway Load Balancer is good at managing third-party virtual applications and makes the user easily deploy and scale the appliances. It gives the distribution of traffic from one gateway across multiple virtual appliances, in addition to the scaling of up and down based on the requirement. Besides, it also eliminates the potential points of failure, in the network and thus increases the availability. In this kind of load balancer, through Amazon Marketplace, you can find, test, and buy the virtual appliance from third-party vendors directly. This integrated experience streamlines the deployment process from the virtual appliances more quickly, irrespective of the same (or) the different vendors.

Classic Load Balancer:

This kind of load balancer is good at both the request as well as the connection level to provide the basic load balancing across the multiple Amazon Ec2 Instances. This kind of load balancer is intended for the applications that were built within the EC2 Classic Network. Amazon has recommended this load balancer kind for Layer 7 traffic and Network load balancer for Layer 4 traffic while using the Virtual Private Cloud (VPC).

This elastic load balancer offers a variety of features to its users. They are:

  • Support of both Ipv4 and Ipv6 protocols
  • Flexible cipher support
  • Spreading instances across the healthy channels
  • Detection of unhealthy Elastic Cloud Computing (EC2) instances
  • Optional public key authentication
  • Centralized management of Secure Socket Layer (SSL) certificates

In addition, there are two other features of Elastic Load balancer, that user uses this service,

Automatic Scaling:

Today developers use the AWS Auto Scaling feature, to guarantee that the user has enough EC2 instances running behind an ELB. Through ELB, developers can set the auto-scaling conditions and once the conditions are met, a new instance can spin up to meet up the minimum. In addition, a developer can also set up the condition, to spin up the new EC2 instance to reduce the latency.


Elastic Load Balancer supports applications within an Amazon Private Cloud (VPC) for stronger network security. Here the IT Teams can specify whether he wants an internal load balancer (or) not. The latter option also enables the developer to route the traffic using ELB using a private IP address.  In addition, the developer can also route the traffic between different tiers of any application using multiple internet-facing and internal load balancers to use a security group along with the private IP address while exposing only the web-facing tier and its public IP address. In addition, it also supports SSL Security encryption.

Likewise, there are many high lighting features of Elastic Load Balancer.  By reaching the end of this article, I hope you have gained enough information on Elastic load Balancer.  You can get a practical explanation on the same, from real-time industry experts through the AWS Online Course. In the upcoming post of this blog, I'll be sharing detailed information on different kinds of load balancers. Meanwhile, check out our AWS Interview Questions prepared by Industry professions to get placed in MNC’s.