Application Gateway and Load Balancer are both used to manage incoming requests to an application, but they serve different purposes.
A Load Balancer is used to distribute incoming network traffic across multiple servers in a cluster to ensure high availability and reliability. It receives incoming requests and routes them to one of the servers in the cluster based on a predefined set of rules. Load balancers can also perform health checks to detect failed servers and route traffic away from them. Load balancers are typically used to improve the scalability and availability of web applications.
On the other hand, an Application Gateway is a layer of abstraction that sits between a client and a set of backend services. It serves as a single entry point for all clients to access the backend services. An Application Gateway can perform a variety of functions such as routing requests, aggregating data from multiple services, and providing authentication and authorization. It can also handle cross-cutting concerns such as logging, monitoring, and rate limiting. Application Gateway is typically used in microservices architecture to simplify the communication between services and to provide a unified interface to clients.
Gateways: Directing Traffic to the Right Destination
Imagine gateways as the entry points to your application's domain, responsible for directing incoming traffic to the appropriate destinations based on predefined rules and criteria. These gateways serve as the first line of defense for your infrastructure, controlling access and ensuring that requests are routed securely and efficiently.
Within the AWS ecosystem, gateways come in various forms, including Internet Gateways and NAT Gateways. An Internet Gateway serves as a bridge between your VPC (Virtual Private Cloud) and the internet, enabling outbound and inbound traffic to flow seamlessly. On the other hand, a NAT Gateway facilitates outbound internet traffic from instances within a private subnet, allowing them to access external resources while maintaining security and privacy.
Load Balancers: Distributing Workloads Across Resources
Load balancers, on the other hand, operate as traffic managers, evenly distributing incoming requests across multiple backend resources to optimize performance and reliability. Think of load balancers as the conductors of a symphony orchestra, orchestrating the flow of traffic to ensure that no single resource is overwhelmed, while maintaining high availability and fault tolerance.
In AWS, load balancers come in different flavors, each tailored to specific use cases and requirements. The Application Load Balancer (ALB) excels at routing HTTP and HTTPS traffic to backend targets based on sophisticated criteria such as content-based routing and containerized applications. Meanwhile, the Classic Load Balancer (CLB) offers a more traditional approach, evenly distributing traffic across instances within a single Availability Zone or across multiple zones.
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