Elastic Load Balancing: Dedicating Traffic to Achieve High Availability

It is of utmost importance that your application handles millions of requests at a time in this digital fast-paced environment. An overloaded server can cause service disruptions, loss of customers, and damage to your reputation. Elastic Load Balancing is the answer AWS has for this challenge. This is a traffic cop, constantly distributing incoming application traffic across multiple targets for availability, scalability, and fault tolerance.

This blog goes through how Elastic Load Balancing works, what are the types of Elastic Load Balancing, and how it can help to build resilient architectures.

Elastic Load Balancing is an intermediary that acts between the users and the application servers. It dynamically spreads incoming traffic across multiple resources like Amazon EC2 instances, containers, and IP addresses. This is how it works:

1. Traffic Distribution

• ELB distributes incoming requests across multiple targets to avoid overloading a single target.
• Traffic distribution is intelligent by the nature of choosing between availability or response time-based decisions.

2. Health Checks

• ELB periodically checks and monitors the health of every target in a target group.
• It automatically stops the flow of traffic to an unhealthy target until such time that the target regains health.

3. Scalability Elasticity

• ELB integrates with Auto Scaling to dynamically scale the number of instances depending on the traffic demand. It thus ensures high performance at all times.

AWS offers several types of load balancers, each suited for different use cases:

1. Application Load Balancer (ALB)

• This is designed for HTTP and HTTPS traffic.
• It supports advanced routing based on request parameters like URLs, headers, and cookies.
• It is ideal for microservices and container-based applications.

2. Network Load Balancer (NLB)

• Handles TCP, UDP, and TLS traffic at the connection level.
• Optimized for ultra-low latency and high-throughput workloads.
• Ideal for applications such as gaming or real-time communication.

3. Gateway Load Balancer

• Enables third-party virtual appliances to be deployed in a highly available and scalable manner.
• Ideal for firewalls, monitoring systems, and other network appliance integration.

4. Classic Load Balancer (CLB)

• Works at both Layer 4 (TCP) and Layer 7 (HTTP).
• Legacy option suitable for basic load balancing needs.

High Availability

• Elastic Load Balancer spreads traffic across several Availability Zones to ensure that an application remains running.

2. Automatic Scaling

• ELB automatically scales as the amount of traffic grows or shrinks, without manual intervention.

3. Secure Traffic Handling

• Elastic Load Balancer supports SSL/TLS termination to provide secure communication between clients and servers.
• Integrates with AWS Certificate Manager (ACM) to easily manage certificates.

4. Access Logs

• It maintains detailed logs of incoming requests that can be stored in Amazon S3 for auditing and analytics.

5. Session Stickiness

• Guarantees a user's requests will go to the same target throughout the session.

6. Custom Routing

• ALB supports path-based and host-based routing for sending traffic to specific targets.

E-Commerce Platforms

• Sends traffic evenly across multiple servers during flash sales or promotional events.
• No single server will be a bottleneck.

2. Microservices Architectures

• Directs traffic to particular services depending on the request path. It facilitates effective communication between microservices.

3. Real-Time Applications

• NLB is suitable for gaming, financial trading, or live streaming applications, with high throughput and low latency.

4. Hybrid Environments

• Gateway Load Balancer makes it easier to integrate appliances from on-premises environments into AWS.

Imagine a video streaming platform that reaches millions of users across the globe. The streaming platform utilizes Elastic Load Balancing for:

• Distribute Requests: ALB forwards HTTP/HTTPS requests to several streaming servers.
• Handling High Traffic: NLB accepts TCP-based streaming traffic with latency close to zero.
• Security: SSL termination ensures all communications between the user and servers are encrypted.
• Scaling Seamlessly: ELB works in unison with Auto Scaling to help it scale according to the rising demand during events.

The ELB helps ensure uninterrupted service to users and delivers a seamless user experience, especially at peak times.

Elastic Load Balancing is more than just a distributor of traffic - it's part of the fundamentals of resilient architecture. Here's why it becomes indispensable:

Benefits:

• Availability: Sends traffic to several different targets and Availability Zones.
• Security: Supports SSL/TLS encryption with integration to AWS WAF that provides application-layer security.
• Costs: Automatically scaling resources to get rid of unnecessary over-provisioning.
• Operational Simplicity: Elimination of the management complexity of your traffic.

With Elastic Load Balancing, businesses can build scalable, secure, and fault-tolerant applications that deliver consistent performance to users worldwide.