how many load balancer in aws

Amazon Web Services (AWS) provides a wide range of cloud computing services to help businesses build and run applications in the cloud. One of the key components of AWS is the load balancer, which distributes incoming traffic across multiple instances or servers to improve performance, availability, and scalability. In this article, we will explore the different types of load balancers available in AWS and how many you may need for your application.

Elastic Load Balancer (ELB)

AWS offers three types of load balancers: the Classic Load Balancer, the Application Load Balancer, and the Network Load Balancer. The Classic Load Balancer is the oldest and most basic type, while the Application Load Balancer and Network Load Balancer are newer and more advanced. However, all three types are collectively known as Elastic Load Balancers or ELBs. The number of ELBs you need in AWS depends on a variety of factors, such as the size and complexity of your application, the amount of traffic it receives, and the level of availability and redundancy required. Generally speaking, you should have at least one ELB to distribute traffic across multiple instances or servers, and you may need multiple ELBs for failover and high availability purposes.

Classic Load Balancer

The Classic Load Balancer is the most straightforward type of ELB. It operates at the transport layer (Layer 4) of the OSI model and supports TCP and SSL protocols. It can distribute traffic across multiple Availability Zones (AZs) and instances within the same region, and can scale up or down automatically based on demand. However, it lacks some of the more advanced features of the newer load balancers, such as path- and host-based routing.If you are using the Classic Load Balancer, you may need multiple instances of it to handle high traffic or ensure high availability. For example, you could deploy two load balancers in different AZs and use Route 53 (AWS's DNS service) to perform a failover between them in case of an outage.

Application Load Balancer

The Application Load Balancer is a more advanced type of ELB that operates at the application layer (Layer 7) of the OSI model. It supports HTTP and HTTPS protocols and can perform path- and host-based routing, allowing you to direct traffic to different services or applications based on the URL or hostname of the request. It also supports content-based routing, which allows you to route traffic based on the content of the request (such as cookies or headers).If you are using the Application Load Balancer, you can configure it with multiple target groups to handle different types of traffic or applications. For example, you could have one target group for your web application servers and another for your API servers, and route traffic accordingly. You may also need multiple instances of the Application Load Balancer for high traffic or redundancy purposes.

Network Load Balancer

The Network Load Balancer is the newest and most powerful type of ELB. It operates at the transport layer (Layer 4) of the OSI model and supports TCP, UDP, and TLS protocols. It can handle millions of requests per second, and provides ultra-low latency and high throughput for applications that require high performance, such as gaming or streaming. It also supports static IP addresses, which can be useful for integrating with on-premises applications.If you are using the Network Load Balancer, you may only need one instance of it to handle all your traffic, as it is designed for high scalability and availability. However, you may still want to deploy multiple instances in different AZs for redundancy and failover purposes.

Conclusion

In summary, AWS offers multiple types of load balancers to help you distribute traffic across instances or servers in the cloud. The number of load balancers you need depends on your application's size, complexity, and requirements for availability and redundancy. As a general rule, you should have at least one load balancer and may need multiple load balancers for high traffic or availability purposes. Consider the different types of load balancers available in AWS and their respective features and capabilities to choose the best option for your application.