In August 2016, Amazon Web Services (AWS) introduced Application Load Balancer for Layer 7 load balancing of HTTP and HTTPS traffic. The new product added several features missing from AWS’s existing Layer 4 and Layer 7 load balancer, Elastic Load Balancer, which was officially renamed Classic Load Balancer.
A year later, AWS launched Network Load Balancer for improved Layer 4 load balancing, so the set of choices for users running highly available, scalable applications on AWS includes:
- NGINX Open Source and NGINX Plus
- Classic Load Balancer
- Application Load Balancer (ALB)
- Network Load Balancer (NLB)
In this post, we review ALB’s features and compare its pricing and features to NGINX Open Source and NGINX Plus.
Notes –
- The information about supported features is accurate as of July 2020, but is subject to change.
- For a direct comparison of NGINX Plus and Classic Load Balancer (formerly Elastic Load Balancer or ELB), as well as information on using them together, see our previous blog post.
- For information on using NLB for a high‑availability NGINX Plus deployment, see our previous blog post.
Features In Application Load Balancer
ALB, like Classic Load Balancer or NLB, is tightly integrated into AWS. Amazon describes it as a Layer 7 load balancer – though it does not provide the full breadth of features, tuning, and direct control that a standalone Layer 7 reverse proxy and load balancer can offer.
ALB provides the following features that are missing from Classic Load Balancer:
- Content‑based routing. ALB supports content‑based routing based on the request URL,
Hostheader, and fields in the request that include standard and custom HTTP headers and methods, query parameters, and source IP address. (See “Benefits of migrating from a Classic Load Balancer” in the ALB documentation.) - Support for container‑based applications. ALB improves on the existing support for containers hosted on Amazon’s EC2 Container Service (ECS).
- More metrics. You can collect metrics on a per‑microservice basis.
- WebSocket support. ALB supports persistent TCP connections between a client and server.
- HTTP/2 support. ALB supports HTTP/2, a superior alternative when delivering content secured by SSL/TLS.
(For a complete feature comparison of ALB and Classic Load Balancer, see “Product comparisons” in the AWS documentation.)
ALB was a significant update for AWS users who had struggled with Classic Load Balancer’s limited feature set, and it went some way towards addressing the requirements of sophisticated users who need to be able to secure, optimize, and control the traffic to their web applications. However, it still does not provide all the capabilities of dedicated reverse proxies (such as NGINX) and load balancers (such as NGINX Plus).
#load balancing #elastic load balancing (elb) #amazon web services #aws
