AWS ELB (Elastic Load Balancer)

Load balancer is a service which uniformly distributes network traffic and workloads across multiple servers or cluster of servers. Load balancer in AWS increases the availability and fault tolerance of an application. AWS Elastic Load Balancer is the single point of contact to all the clients, they can be sent to the nearest geographic instance or the instance with the lowest latency.

AWS Load balancer will distribute your workloads across multiple compute resources, such as a Virtual Machine or Virtual Server. The application availability and failover will decrease due to this. You can also let your load balancer take care of your encryption and decryption and let your compute services do their main work.

There are mainly three types of Amazon load balancers:

Classic Load Balancer

Network Load Balancer

Application Load Balancer

Classic Load balancer in AWS is used on EC2-classic instances. This is the previous generation’s load balancer and also it doesn’t allow host-based or path-based routing.

The Classic Load balancer will route traffic to all registered targets in the Availability Zones, it doesn’t check what is in the servers in those targets. It routes to every single target. Mostly it is used to route traffic to one single URL.

Network Load Balancer in AWS takes routing decisions in the Transport layer (TCP/SSL) of the OSI model, it can handle millions of requests per second. Widely used to load balancing the TCP traffic and it will also support elastic or static IP.

Let us see a simple example, you own a video sharing website which has decent traffic every day. One day, after a video on your website, went viral the website’s traffic is very high and you need an immediate solution to maintain it. AWS Network Load Balancer to the rescue!

AWS Network Load Balancer can be trusted in these types of situations. It can handle millions of requests and a sudden spike of traffic because it works at the connection level.

An Application Load Balancer in AWS makes routing decisions at the application layer (HTTP/HTTPs) of the OSI model, thus the name Application Load Balancer. ALB supports path-based and host-based routing, we will look at them after learning how the ALB works.

The Application Load Balancer receives the route requests, then it inspects the received packets. Then it chooses the best target possible for the type of load and sends to the target with the highest efficiency.

ELB distributes traffic evenly among all the targets, for example, multiple EC2 instances.

ELB has an SLA of 99.99%

ELB let’s you route traffic with the application’s IP address, this allows you launch multiple applications in a single instance.

You can implement robust security features using Amazon VPC with Amazon ELB

ELB can handle sudden spikes in traffic and can handle millions of requests per second. Whenever there is a traffic increase, an auto-scaling feature will be enabled, and also load balancing rules will be used to provide the website users a seamless performance

You can use the same Amazon load balancer to balance across applications on your on-premises set up and your AWS infrastructure. Now, it will be very easy to migrate your application from on-premise to AWS cloud.

Applications and their performance can be monitored and maintained. You can also use CloudWatch metrics and logs to analyze our applications data, traffic, and working