Merge pull request terraform-aws-modules#517 from stakater/add-notes

[add-notes] update local.tf file
michyweb · Sep 20, 2019 · 0cc058c · 0cc058c
2 parents f702467 + 185cd44
commit 0cc058c
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Showing 2 changed files with 6 additions and 2 deletions.
diff --git a/docs/autoscaling.md b/docs/autoscaling.md
@@ -28,6 +28,10 @@ To install the chart, simply run helm with the `--values` option:
 helm install stable/cluster-autoscaler --values=path/to/your/values-file.yaml
 ```
 
+`NOTE`
+
+There is a variable `asg_desired_capacity` given in the `local.tf` file, currently it can be used to change the desired worker(s) capacity in the autoscaling group but currently it is being ignored in terraform to reduce the [complexities](https://github.com/terraform-aws-modules/terraform-aws-eks/issues/510#issuecomment-531700442) and the feature of scaling up and down the cluster nodes is being handled by the cluster autoscaler.
+
 ## See More
 
 [Using AutoScalingGroup MixedInstancesPolicy](https://github.com/kubernetes/autoscaler/blob/master/cluster-autoscaler/cloudprovider/aws/README.md#using-autoscalinggroup-mixedinstancespolicy)
diff --git a/local.tf b/local.tf
@@ -23,9 +23,9 @@ locals {
     name                          = "count.index"               # Name of the worker group. Literal count.index will never be used but if name is not set, the count.index interpolation will be used.
     tags                          = []                          # A list of map defining extra tags to be applied to the worker group ASG.
     ami_id                        = data.aws_ami.eks_worker.id  # AMI ID for the eks workers. If none is provided, Terraform will search for the latest version of their EKS optimized worker AMI.
-    asg_desired_capacity          = "1"                         # Desired worker capacity in the autoscaling group.
+    asg_desired_capacity          = "1"                         # Desired worker capacity in the autoscaling group and changing its value will not affect the autoscaling group's desired capacity because the cluster-autoscaler manages up and down scaling of the nodes. Cluster-autoscaler add nodes when pods are in pending state and remove the nodes when they are not required by modifying the desirec_capacity of the autoscaling group. Although an issue exists in which if the value of the asg_min_size is changed it modifies the value of asg_desired_capacity.
     asg_max_size                  = "3"                         # Maximum worker capacity in the autoscaling group.
-    asg_min_size                  = "1"                         # Minimum worker capacity in the autoscaling group.
+    asg_min_size                  = "1"                         # Minimum worker capacity in the autoscaling group. NOTE: Change in this paramater will affect the asg_desired_capacity, like changing its value to 2 will change asg_desired_capacity value to 2 but bringing back it to 1 will not affect the asg_desired_capacity.
     asg_force_delete              = false                       # Enable forced deletion for the autoscaling group.
     asg_initial_lifecycle_hooks   = []                          # Initital lifecycle hook for the autoscaling group.
     asg_recreate_on_change        = false                       # Recreate the autoscaling group when LT or LC change.