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This repository was archived by the owner on Jul 3, 2023. It is now read-only.
desired_capacity clashes with alarm-based scaling #63
Description
This is in reference to the ecs-cluster module.
I may be wrong on this (please correct me if I am), but doesn't setting desired_capacity on your autoscaling group conflict with the alarm-based scaling? If your asg is scaling up because of high cpu/memory reservation and you run terraform apply at the same time, it will knock your instance count back down to the number specified in your code (alarm-based scaling modifies the group's desired capacity). See this thread for reference.
desired_capacity is an optional argument for aws_autoscaling_group, so maybe it would be better to take it out (or at least not set a default).
Activity
lukebarton commentedon Mar 17, 2017
At the risk of adding a +1 post, I too am interested in this.
From my understanding, the ASG will scale based on the CPU alert. However from my observations I think there are two issues:
desired_count, meaning Services won't scale with the ASG - new instances will just be empty? Even if the ECS redistributes, this could quite easily lead to a situation where the ASG is constantly scaling up to theecs_max_sizedue to "ServiceA" constantly maxing out the CPU because it's not actually scaling the service across newly available instances.desired_capacity?I'm concerned about both issues.