AWS ECS – Do You Need an Internal Load Balancer for ECS Services?

amazon-ecsamazon-web-servicesaws-fargateload balancing

I have an ECS cluster with 3 services(FARGATE), the 3 services are in private subnets. 1 is the web app that is publicly accessible through an Internet-facing Load Balancer and the 2 others are only accessed from the web app. For internal communication, I'm using Service Discovery names.
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Everything is working but now I'm debating if I need an internal Load Balancer just between the web app and the 2 internal services in case they scale out/in. So, if one of my internal services scales out and I'm using the Service Discovery name for internal communication, it is enough? Or, do I need an internal Load Balancer that can route the traffics to the different service instances?

Does this make sense?
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Best Answer

Service Discovery is enough. New nodes will be added to the SD name resolution when they are started. Unfortunately many people don't know / use Service Discovery and resort to the more expensive ALB. Good on you for using SD :)

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