What is Load Balancing?
AWS Load Balancing, specifically Elastic Load Balancer (ELB), is a service that distributes incoming traffic across multiple targets like EC2 instances. It ensures high availability, scalability, and fault tolerance by automatically routing traffic to healthy instances. ELB supports HTTP, HTTPS, TCP, and UDP traffic. There are different types of load balancers: Application Load Balancer (ALB), Network Load Balancer (NLB), and Classic Load Balancer (CLB). ALB is ideal for web applications, while NLB is for high-performance, low-latency traffic. ELB scales automatically based on incoming traffic demands. It integrates with AWS security services for encryption and access control. ELB offers health checks to ensure traffic is only sent to healthy instances. It can be used in both public and private networks. ELB provides seamless scaling to accommodate fluctuating workloads.
Types of AWS load balancers are.
- Classic Load Balancer (CLB).
- Application Load Balancer (ALB).
- Network Load Balancer (NLB).
- Gateway Load Balancer (GLB).
Classic Load Balancer (CLB).
The Classic Load Balancer (CLB) is one of the original load balancing solutions offered by AWS. It is designed to distribute traffic across multiple EC2 instances, ensuring high availability and fault tolerance for your application. CLB supports both HTTP/HTTPS and TCP/SSL traffic, making it versatile for different use cases. It operates at both Layer 4 (Transport Layer) and Layer 7 (Application Layer) of the OSI model, enabling it to handle various types of protocols and traffic.
While it offers basic load balancing features, it lacks the advanced routing capabilities found in newer solutions like Application Load Balancer (ALB) or Network Load Balancer (NLB). For example, CLB does not support host-based or path-based routing. It is also limited in its support for WebSocket or HTTP/2 protocols.
Despite these limitations, CLB is often used for legacy applications or simple use cases where advanced routing is unnecessary. It integrates easily with other AWS services, such as Auto Scaling and Elastic Load Balancing (ELB), providing seamless scalability for your applications. However, AWS recommends using ALB or NLB for new applications, as they offer better performance and more granular control over traffic routing.
Additionally, CLB supports SSL termination, allowing it to offload the processing of secure connections from backend servers. While CLB provides basic monitoring through CloudWatch metrics, it lacks some of the deeper insights and flexibility available with ALB. Overall, CLB is a reliable choice for simple applications but has been largely superseded by more feature-rich load balancing solutions.
STEP 1: Navigate the EC2 instance Click on Load balancer and create load balancer.
- Select Classic load balance.
STEP 2: Enter the name and select the internal.
STEP 3: Next, Select VPC and Subnet.
STEP 4: Select security group.
STEP 5: Add atleast 2 instance.
STEP 6: Click on create.
Application Load Balancer.
An Application Load Balancer (ALB) in AWS is a fully managed service designed to distribute incoming application traffic across multiple targets, such as EC2 instances, containers, and IP addresses. It operates at the application layer (Layer 7) of the OSI model, enabling routing decisions based on request content, like URL path, host, or HTTP headers. ALB is highly scalable, supporting thousands of requests per second, and is ideal for microservices, containerized applications, and HTTP/HTTPS traffic. It allows users to configure advanced routing rules, enabling direct routing to specific services or containers based on URL patterns or query strings.
ALB supports both IPv4 and IPv6 addresses and can automatically scale to handle varying levels of incoming traffic. It integrates with AWS services such as Amazon ECS, EKS, and Lambda, making it suitable for modern, cloud-native architectures. Additionally, it offers built-in SSL termination, ensuring secure connections without needing to manage SSL certificates manually. Security groups and AWS Web Application Firewall (WAF) can be used with ALB to protect against common web exploits and attacks.
ALB provides detailed metrics and logging for monitoring and troubleshooting, making it easier for developers to track performance and diagnose issues. Unlike Classic Load Balancers, ALB offers more granular control over routing and traffic management, supporting features like path-based and host-based routing, WebSocket support, and HTTP/2. Furthermore, ALB helps improve application performance by reducing latency through intelligent traffic distribution and health checks to ensure high availability.
STEP 1: Go to load balancer and select application load balancer click on create.
STEP 2: Select VPC and Subnets.
STEP 3: Next, Select your default security group.
STEP 4: Select your created target group and click on create load balancer.
Network Load Balancer.
A Network Load Balancer (NLB) in AWS is a highly scalable and performant service designed to handle large amounts of traffic at the transport layer (Layer 4) of the OSI model. Unlike the Application Load Balancer, which operates at the application layer, NLB is optimized for extreme performance, low latency, and high throughput, making it ideal for handling TCP, UDP, and TLS traffic. NLB is capable of handling millions of requests per second, and it is designed to efficiently manage both static and dynamic workloads. It is well-suited for applications that require high availability, such as real-time communication systems or gaming platforms.
NLB can distribute traffic across multiple targets, such as EC2 instances, containers, and IP addresses, in a highly available and fault-tolerant manner. It supports automatic scaling, ensuring that it can dynamically adjust to changing traffic patterns and load levels without manual intervention. The NLB can also handle traffic with very low latency, providing faster response times for end users.
NLB also supports TLS termination, allowing it to offload encryption/decryption tasks from the backend servers. It can be easily integrated with services like Amazon EC2 and AWS Auto Scaling, providing flexibility in managing dynamic workloads. Furthermore, NLB supports health checks to ensure traffic is only sent to healthy targets. It also offers enhanced security through the use of security groups and network ACLs to control access to resources. Unlike ALB, NLB is highly optimized for applications that need to operate at the network layer and require high performance, scalability, and low latency.
Gateway Load Balancer.
A Gateway Load Balancer (GWLB) in AWS is a fully managed service designed to simplify the deployment, scaling, and management of third-party virtual appliances, such as firewalls, intrusion detection systems, and deep packet inspection devices. It operates at the network layer (Layer 3) and integrates with Amazon VPC to route traffic through the appliances, providing scalability and availability for network security or monitoring tools. GWLB is particularly useful for organizations that need to inspect, filter, or manipulate traffic before it reaches their application servers.
GWLB allows users to deploy virtual appliances without needing complex configurations, such as managing individual network interfaces or manually distributing traffic. Instead, it provides a central, highly available endpoint that can distribute traffic across multiple appliances, automatically scaling to handle changes in traffic load. This helps eliminate single points of failure, ensuring continuous protection and security.
GWLB supports a simple architecture where network traffic is directed through the load balancer to the selected appliances and then back to the destination. It also supports transparent traffic inspection by forwarding the original source and destination IP addresses, making it easy for appliances to analyze the traffic as it appears in the original form.
Additionally, GWLB provides deep integration with AWS services, such as Amazon EC2, Security Groups, and AWS Transit Gateway, enabling flexible and seamless deployment. It allows easy integration with third-party security and networking services from AWS Marketplace, helping organizations enhance their security posture without disrupting the flow of application traffic.
Security features of GWLB include the ability to protect against unauthorized access and ensure that only approved appliances can handle traffic. It can also be combined with AWS services like AWS Firewall Manager and AWS Security Hub for centralized security management. Another key benefit of using GWLB is its ability to handle both outbound and inbound traffic inspection, making it ideal for scenarios requiring end-to-end security analysis.
With support for auto-scaling, high availability, and seamless integration with AWS VPC, Gateway Load Balancer offers a powerful, flexible solution for organizations looking to simplify and scale their network security architecture while minimizing complexity and operational overhead.
Conclusion.
In conclusion, AWS Elastic Load Balancer (ELB) provides a powerful, flexible solution for distributing incoming application traffic across multiple targets to ensure high availability, scalability, and fault tolerance. Understanding the three main types of ELBs—Application Load Balancer (ALB), Network Load Balancer (NLB), and Gateway Load Balancer (GWLB)—is crucial for choosing the right load balancing solution based on your application’s needs.
ALB is ideal for HTTP/HTTPS-based applications with advanced routing requirements, including path-based and host-based routing. NLB excels at handling high-performance, low-latency traffic for TCP/UDP applications, offering unmatched scalability and reliability for real-time services. GWLB simplifies the deployment of third-party network appliances, such as firewalls or intrusion detection systems, while providing seamless traffic inspection and high availability.
Each type of ELB integrates well with AWS’s ecosystem of services, allowing you to improve security, enhance performance, and reduce operational complexity. Whether you’re building modern microservices, running traditional applications, or securing network traffic, AWS ELB provides the tools to meet diverse requirements with ease. By selecting the appropriate load balancer, organizations can ensure their applications perform efficiently and securely, while also remaining scalable and adaptable to future demands.
