In this post, I will be covering Amazon Elastic Load Balancing (ELB). Its overview, features, and types.
Elastic Load Balancing (ELB) is a load-balancing service for AWS deployments. It automatically distributes incoming application traffic and scales resources to fulfill high traffic demands.
AWS Elastic Load Balancing (ELB)
- Distributes incoming application traffic across multiple targets, such as EC2 instances, containers (ECS), Lambda functions, and IP addresses in multiple Availability Zones(AZs).
- Distributes Client traffic across servers.
- Improves the performance of applications.
- It Accepts incoming traffic from clients and routes requests to its registered targets.
- Monitors the condition of its registered targets and routes traffic only to healthy targets.
- Enable deletion protection to stop your load balancer from being deleted accidentally. Disabled by default.
- Deleting ELB won’t delete the instances registered to it.
- Cross Zone Load Balancing – If enabled, each load balancer node automatically distributes traffic across the registered targets in all enabled AZs.
- Supports SSL Offloadirig which is a feature that allows the ELB to bypass the SSL termination by removing the SSL-based encryption from the incoming traffic.
Most Common Features
The most common service that relies on ELB is Amazon’s EC2 Instances, as ELB performs a health checkup to confirm an instance continues to be running before sending traffic thereto. A developer can integrate Amazon Route 53 and Domain name system (DNS) failover to further boost application resiliency.
A developer can use the AWS Auto Scaling feature to ensure he or she has enough EC2 instances running behind an ELB. The developer sets Auto Scaling conditions, and when a condition is met, a brand new EC2 instance can spin up to satisfy the specified minimum. A developer also can set a condition to spin up new EC2 instances to scale back latency.
ELB supports applications within an Amazon VPC for stronger network security. An IT team can specify whether it wants an internet-facing or internal load balancer. The latter option enables a developer to route traffic through an ELB using private IP addresses.
Also read: All you need to know about AWS Free Tier Account Services
Types Of Load Balancers
In AWS we have 3 types of Load Balancer
- Classic Load Balancer
- Application Load Balancer
- Network Load Balancer
Classic Load Balancer
- The Load Balancer which balances the traffic across multiple instances in multiple availability zones is called a Classic Load Balancer.
- It supports both EC2 Classic EC2-VPC and Increases the availability of your application by sending traffic to healthy Instance.
- Supports HTTP, HTTPS, TCP, and SSL listeners and supports sticky sessions using application generated cookies.
- To make ensure that your registered instances are able to handle the request load In each AZ, keep approximately the same number of instances In each AZ registered with the load balancer.
Network Load balancer
- Network Load Balancer handles sudden and violates traffic across the EC2 Instances in order to avoid any latency.
- Connection baseload Balancing and it supports TCP protocol.
- Ability to handle volatile workloads and scale to millions of requests per second.
- Support for static IP addresses for the load balancer. or assign one Elastic IP address per subnet enabled for the load balancer.
- Cross-zone load balancing is disabled by default
- If you specify targets using an instance ID, the source IP addresses of the clients are preserved and provided to your applications. If you specify targets by IP address, the source IP addresses are the private IP addresses of the load balancer nodes.
- Network Load Balancers support connections from clients over inter-region VPC peering. AWS managed VPN, and third-party VPN solutions.
Application Load balancer
- The Load Balancer that distributes the traffic to appropriate target groups on the basis of content is called Application Load Balancer.
- New feature-rich, layer 7 load balancing platform.
- Supports web sockets, HTTP, HTTPS, and microservices and container-based applications, including deep integration with EC2 container service.
- Support for path-based and host-based routing. Also, provide routing requests to multiple applications on a single EC2 instance.
- Cross-Zone load balancing is always enabled and you can also specify Lambda functions are targeted to serve HTTP(S) requests.
- Supports load balancer-generated cookies only for sticky sessions.
Difference Between Application, Classic, And Network Load Balancer
Elastic Load Balancing is a proven mechanism of distributing application and web traffic requests across multiple targets or instances. ELB allows you to scale your varying workloads automatically. We have also seen the three types of load balancers used in ELB and its key features.
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- Overview of Amazon Web Services & Concepts
- AWS Certified Solutions Architect Associate SAA-C02
- AWS Management Console Walkthrough
- Elastic Load Balancer
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