ECS Instance Draining on Scale In

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Heavily inspired by this AWS blog post, this module deploys resources and code to support ECS Instance Draning and ASG lifecycle hook to ensure that running tasks are not obliterated by ASG scale-in events.

Further details about AutoScaling Lifecyle Hooks is available.

Module Input Variables

• region - The AWS Region where the resources reside.
• autoscaling_group_name - The Name of the AutoScaling Group used by the ECS Cluster.
• cluster_name - The Name of the ECS Cluster to target
• function_sleep_time - Number of seconds the Lambda function should sleep before checking ECS Instance Task Count again. Defaults to 15 seconds.
• hook_heartbeat_timeout - Amount of time, in seconds, the lifecycle hook should wait before giving up and moving onto the default result. Defaults to 900 (15 mins).
• hook_default_result - Can be one of either ABANDON or CONTINUE. ABANDON stops any remaining actions, such as other lifecycle hooks, while CONTINUE allows any other lifecycle hooks to complete. Default is ABANDON
• enabled - boolean expression. If false, the Lifecycle Hook is removed from the AutoScaling Group. Defaults to true.

Usage

resource "aws_autoscaling_group" "ecs" {
  #properties omitted
}

module "ecs_instance_draining_on_scale_in" {
  source = "github.com/terraform-community-modules/tf_aws_ecs_instance_draining_on_scale_in"

  region = "eu-west-1"
  autoscaling_group_name = "${aws_autoscaling_group.ecs.asg_name}"
  cluster-name = "my-cluster"
  hook_heartbeat_timeout = 1800
  hook_default_result    = "ABANDON"
}

Author

Created and maintained by Shayne Clausson