Registering multiple target groups for ECS service

Question

Hello

Is registering multiple target groups to an ECS service a good practice?

One can think that if I attach multiple target groups where each target group is used in a separate load balancer, where one load balancer handles internal traffic and another load balancer handles external traffic from internet, does that introduce load imbalances between instances of the target groups? If so can these imbalances become so severe that I might need to have separate ECS service altogether to handle external traffic and another ECS service to handle internal traffic?

Thanks

Answer

Hi,

The use of multiple target groups could be useful if you are trying to implement patterns such as the ones mentioned [here.](https://docs.aws.amazon.com/AmazonECS/latest/developerguide/register-multiple-targetgroups.html#multiple-targetgroups-examples)

Since you are using ECS [it is designed with a focus on scaling], you don't need to create another service [manually] for internal and external needs, instead you can [automatically scale your Amazon ECS service](https://docs.aws.amazon.com/AmazonECS/latest/developerguide/service-auto-scaling.html) based on a metric/alarm/shedule.

As with any solution, it could be necessary to load test it to verify your configurations (Task, Service, ALB, Auto-scaling) can serve real-world loads. I suggest you go through this guide [Distributed Load Testing on AWS](https://docs.aws.amazon.com/solutions/latest/distributed-load-testing-on-aws/solution-overview.html).

Hope this helps!

Thanks,
Rama

Registering multiple target groups for ECS service

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