Elastic Load Balancer
Definition
AWS service that distributes incoming traffic across multiple servers to prevent overload, enhancing application performance and reliability.
Use Cases
- Netflix: Handle large volumes of user traffic to streaming and API services with high availability across many instances. — Netflix runs on AWS and uses load balancing patterns extensively; AWS Elastic Load Balancing is commonly used in AWS architectures to distribute traffic across fleets of instances and services, typically paired with auto scaling and health checks to route around unhealthy targets. (Improved resilience and the ability to scale services horizontally to meet variable demand while maintaining service availability.)
- Airbnb: Distribute web and API traffic across multiple application servers to support spikes in user activity. — Airbnb has publicly described operating on AWS for significant parts of its infrastructure; in typical AWS deployments, Elastic Load Balancing is used in front of application tiers to spread requests across instances and to perform health-based routing. (More consistent performance during traffic spikes and reduced risk of single-server overload.)
Provider Equivalents
- AWS: Elastic Load Balancing (ELB) — Application Load Balancer (ALB), Network Load Balancer (NLB), Gateway Load Balancer (GWLB)
- Azure: Azure Load Balancer; Azure Application Gateway
- GCP: Google Cloud Load Balancing (External/Internal HTTP(S), TCP/SSL, UDP)
- OCI: OCI Load Balancer
Frequently Asked Questions
- What's the difference between Elastic Load Balancer and Amazon CloudFront?
- Elastic Load Balancing distributes incoming requests to multiple servers (targets) to improve availability and handle more traffic. Amazon CloudFront is a CDN that caches and serves content from edge locations closer to users. A common pattern is CloudFront in front (for caching and global performance) and an ELB behind it (to distribute requests to your application servers).
- When should I use Elastic Load Balancer?
- Use ELB when you have more than one backend server (or plan to scale to multiple) and you want automatic traffic distribution, health checks, and higher availability. It’s especially useful for production web apps, APIs, microservices, and any workload where you need to handle variable traffic without overloading a single instance.
- How much does Elastic Load Balancer cost?
- ELB pricing depends on the load balancer type (ALB, NLB, GWLB), how long it runs, and how much traffic it processes. Common cost drivers include hourly (or per-time) charges and usage-based metrics (for example, processed bytes, connections, or request-related capacity units depending on the ELB type). You should estimate using the AWS Pricing Calculator and consider additional costs for data transfer and the targets behind the load balancer.
Category: networking
Difficulty: intermediate
Related Terms
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