what is target group in aws load balancer

Load balancers are essential components in cloud computing. They help distribute traffic to several servers that form part of a scalable and highly available infrastructure. Amazon Web Services (AWS), one of the biggest cloud providers in the world, offers load balancing to its clients through three main products - the Elastic Load Balancer, Application Load Balancer, and Network Load Balancer. This article focuses on the target group in AWS load balancer, what it is, and why it is important.

What is a Target Group?

A target group is a set of resources (either EC2 instances, IP addresses, or Lambda functions) that receive traffic from the load balancer. AWS load balancers direct incoming traffic to the corresponding target groups based on the rules set. Each target group has its own health check settings and traffic routing policy.The Amazon Elastic Compute Cloud (EC2) instances that form the target group can reside in different Availability Zones or regions, ensuring high availability and fault-tolerance. Amazon EC2 Auto Scaling groups can be associated with target groups, allowing for automated scaling and load distribution based on user-defined metrics such as CPU utilization and network traffic.

Target Group Types

AWS offers three types of target groups: instance, IP, and Lambda. The instance target group route traffic to EC2 instances that are identified by their IDs, IPs, or tags. This group gives administrators complete control over the instances to which the load balancer routes traffic. The IP target group route traffic based on the IP address of a specific target. This group is useful for routing traffic to static IP addresses that are not tied to an instance's life cycle. The third target group type is the Lambda function target group, which routes traffic to a specific version of a Lambda function. This group allows for easy scalability by adopting a serverless infrastructure model.

Why Target Groups are Important

Target groups allow for enhanced routing functionality in load balancing. They offer more granular control over traffic routing and distribution, allowing administrators to route requests to specific groups of resources based on metrics such as load, responsiveness, and geographic location.Additionally, target groups help ensure that traffic is directed to healthy resources by performing health checks on the associated resources. The load balancer constantly checks the health of the resources in the target group. If an instance fails the health check, it is removed from the target group and traffic routed to a healthy resource.Moreover, target groups facilitate scaling of the infrastructure. AWS load balancers help automate scaling of EC2 Auto Scaling groups based on target tracking metrics. Target tracking ensures that the desired capacity of the resource group remains at the specified percentage of the target group’s metrics.

Conclusion

In summary, target groups are critical to effective load balancing in AWS. They provide granular routing functionality, health checks, and automated scaling, helping to ensure high availability, scalability, and fault tolerance in cloud computing. AWS provides three main types of target groups- instance, IP, and Lambda- each catering to different types of resources. Understanding target groups is fundamental to optimizing the use of AWS load balancers for a scalable and highly available infrastructure.