[EKS] [request]: Desired size should be set to current amount for update nodegroup

[dza89]

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Tell us about your request
When you update a nodegroup you have to pass the desired size.
This field should be only be actively used when creating a nodegroup, and not during a nodegroup update.

Which service(s) is this request for?
EKS

Tell us about the problem you're trying to solve. What are you trying to do, and why is it hard?
Create nodegroup -> forward desired size
Update nodegroup -> ignore desired size, and set desired in the asg to the current amount of nodes, as this should be controlled by cluster autoscaler only.

Are you currently working around this issue?
Not

Additional context
Anything else we should know?

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[MyannaHarris]

Hi @dza89 ,
Are you still seeing this issue? The AWS CLI doesn't require all sizes to be entered and we made a change recently so updating the managed nodegroup through CFN shouldn't have this issue anymore. eksctl also recently put out a fix for this issue (eksctl-io/eksctl#3532). If you're still seeing this, please let us know how you're calling EKS so we can investigate some more.
(Correcting my wording)

[dza89]

@MyannaHarris
I don't know what 'our' cli is, I guess the aws-cli?
I still see this issue, but maybe I don't understand what the solution should be?
I tried to update the nodegroup without the desiredAmount parameter, but it errored. How should I approach this?

Also, eksctl does not contain a fix, but a workaround; by getting the current amount of nodes from the asg and inserting that as desired amount, which is what I am doing as well, but should not be necessary tbh.

[dza89]

@MyannaHarris
Maybe it wasn't rolled out in eu-west-1?
DesiredAmount is no longer mandatory in the scaling config, it's working now :)
Thanks!

[dza89]

@MyannaHarris

This is missing when updating the scaling config without the desiredSize.

if MaxAmount < desiredSize {
  desiredSize = MaxAmount
} else if MinAmount > desiredSize {
  desiredSize = MinAmount
}

[MyannaHarris]

@dza89
Glad it's working for you now!
eksctl is different but the CLI and CFN templates should allow the desiredSize parameter to be omitted.

We still require that the maxSize >= desiredSize >= minSize and currently don't have any plans to automatically and permanently alter a customer's desiredSize. If this is an important feature for you to have, please open a new feature request specifically for it so we can investigate.

Thank you for checking this and please let us know if you have any other questions.

[dza89]

OK, thanks for your input and help.

Last comment:
If I have a nodegroup with min 1 max 2 and I want to increase it to min 3 max 4, I still have to feed it the desired size, hence my previous comment.