fix(kb/aws): improve load balancing notes

This commit is contained in:
Michele Cereda
2026-01-05 20:59:33 +01:00
parent 2e9c58f4e0
commit 7043496efc

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@@ -546,6 +546,19 @@ its `path`).
> [!warning]
> ALBs **cannot** rewrite requests' `host` header or path.<br/>
> Use [CloudFront] or other solutions like custom forwarder or [Lambda functions] instead.
>
> FIXME: since 2025-10-15, it looks like they can by using Rule Transforms.<br/>
> Check the [news post](https://aws.amazon.com/about-aws/whats-new/2025/10/application-load-balancer-url-header-rewrite),
> the [blog post](https://aws.amazon.com/blogs/networking-and-content-delivery/introducing-url-and-host-header-rewrite-with-aws-application-load-balancers/),
> and [Rule Transforms](https://docs.aws.amazon.com/elasticloadbalancing/latest/application/rule-transforms.html).
The service charges per Load Balancer, per hour it exists. Every _partial_ hour is billed as a full hour.<br/>
It also charges for the number of Load Balancer Capacity Units (LCU) used per minute. When using Load Balancer Capacity
Unit Reservation, any additional number of LCUs used per minute _beyond_ one's reserved LCUs per hour is added to the
bill.
> [!tip]
> To save money, prefer using less ALBs with more than one rule each.
Using rules in AWS application load balancers to redirect by path **keeps the path** in the forwarded request.<br/>
Applications that serve their files using _relative_ paths will not be able to find the resources, as the path will not
@@ -558,11 +571,6 @@ E.g.: given an ALB with a rule forwarding requests for paths matching `/some-app
> [!important]
> This does **not** happen for targets that are tasks to ECS.<br/>
> Those are treated differently by the ALB (insert quotation here), and the requests' path is replaced with `/`.
>
> FIXME: since 2025-10-15, it looks like they can by using Rule Transforms.<br/>
> Check the [news post](https://aws.amazon.com/about-aws/whats-new/2025/10/application-load-balancer-url-header-rewrite),
> the [blog post](https://aws.amazon.com/blogs/networking-and-content-delivery/introducing-url-and-host-header-rewrite-with-aws-application-load-balancers/),
> and [Rule Transforms](https://docs.aws.amazon.com/elasticloadbalancing/latest/application/rule-transforms.html).
Solutions for this include: