AWS Elastic Load Balancing

Elastic Load Balancers (ELB) are managed services designed to distribute incoming application or network traffic across multiple targets, such as Amazon EC2 instances, containers, and IP addresses, within one or more AWS availability zones. ELBs enhance the availability and fault tolerance of applications by evenly distributing traffic and automatically routing it away from unhealthy targets.

Features and Capabilities:

• Auto Scaling Integration: ELBs seamlessly integrate with AWS Auto Scaling, automatically adjusting the number of instances to handle varying levels of traffic.
• Health Checks: ELBs continually monitor the health of registered instances and distribute traffic only to healthy targets, ensuring high availability.
• SSL Termination: ELBs can offload SSL/TLS decryption, relieving the backend instances from the computational load of encryption and improving overall system performance.
• Integrated Security: ELBs can be configured with AWS security features such as AWS WAF (a Web Application Firewall) and AWS Shield (protections against DDoS attacks) for protecting applications against various security threats.
• Content-Based Routing (ALB): Application Load Balancers support content-based routing, allowing you to route requests based on the content of the request.
• IPv6 Support: ELBs support IPv6, allowing applications to handle both IPv4 and IPv6 traffic.

Application Load Balancer (ALB)

ALB operates at the application layer (layer 7) and is ideal for routing HTTP/HTTPS and Websocket traffic. It supports advanced routing features, content-based routing, and enables the integration of AWS services like AWS WAF for enhanced security.

Gateway Load Balancer (GLB)

A service that allows users to deploy, scale, and manage third-party virtual appliances, such as firewalls, intrusion detection and prevention systems, and other security or networking appliances. The Gateway Load Balancer operates at the network level (Layer 3) and enables efficient and flexible routing of traffic to virtual appliances deployed in the AWS environment.

Watch the following video for a basic explanation of the communication flow is which a GLB is part of.

Network Load Balancer (NLB)

NLB functions at the transport layer (layer 4) and is well-suited for handling TCP, UDP, and TLS traffic. It is designed to handle high-throughput, low-latency requirements and is commonly used for applications requiring extreme performance.

Conclusion

Elastic Load Balancers play a crucial role in ensuring the scalability, reliability, and performance of applications hosted on AWS by distributing incoming traffic across multiple targets and availability zones. Organizations can choose the type of load balancer that best suits their application's requirements and easily configure and manage them through the AWS Management Console, CLI, or SDKs.