I've provisioned an Application Load Balancer (ALB) with a single target group that spans two Availability Zones, but I'm noticing that my LCU (Load Balancer Capacity Units) usage is surprisingly high. This target group is connected to an ECS service that runs in both AZs. While I'm working on this project, I often leave it without tasks provisioned, so I'm wondering if the high usage is normal or if there's a way to lower it and reduce my bill. Also, is it possible to contact AWS Support if I don't have a support plan?
2 Answers
From what I understand, the metrics in the capacity tab show the snapshot of capacity used by your ALB, but they aren’t the billing metric you should focus on. The real billing metric is the 'ConsumedLCUs,' which only counts when traffic is going through your ALB. If you’re not sending traffic, you won’t see those charges. However, even when idle, you might still see some 'PeakLCUs.' So, just keep an eye on 'ConsumedLCUs' for your billing.
Your LCU usage seems to peak around 20, which isn't too high. The Free Tier allows 750 hours and up to 15 LCUs. I have one that runs around 5 LCU and it goes up to 10 occasionally, usually when I’m testing. Is your ALB public? If it's accessible to the internet, it could be attracting bot traffic. You might want to check your access logs for weird requests and consider tightening your security group or using CloudFront to help with the traffic.
I've checked and my consumed LCUs are also low, but yes, it's publicly accessible. I'll definitely tighten my security group now.
I also looked at my ALB’s consumed LCUs, and it's low. I opened a support ticket, so hopefully, there’s something up. But this info helps clarify things!