Enable AKS cluster autoscaler

[BernieWhite]

Rule request

Suggested rule change

AKS clusters deployed with scale sets should enable the cluster autoscaler.

Applies to the following

The rule applies to the following:

• Resource type: Microsoft.ContainerService/managedClusters

Additional context

Azure template reference

[ArmaanMcleod]

@BernieWhite I can help make a PR for this rule.

[BernieWhite]

@ArmaanMcleod Great thanks. Let me assign that to you. If you have any issues let me know.

[ArmaanMcleod]

@BernieWhite No worries. When creating the rule for the first time which ruleset tag to do you put it under? I'm assuming I can use 2021_06 since that's the latest.

I also see the following baselines:

Do I also need to referece the rule .md files in here as well? I can include it in Azure.GA_2021_06.md and Azure.All.md. Should it also go into Azure.Default.md?

[BernieWhite]

@ArmaanMcleod The ruleset references the quarterly baseline rules are released in. For new rules this is the next quarterly baseline so the next baseline would be 2021_09. Release GA and preview is determines by the Azure feature, so in this case AKS cluster autoscaler is a GA Azure features so it would be GA.

The quarterly baseline is designed to be a stable checkpoint for customers. So, if they are not ready to adopt new rules immediately, they can target a quarterly baseline and get a stable position even though we add rules each month.

At the end of the quarter, we cut a new baseline and deprecate the old one, which reports as a warning.

You don't need to worry about updating an old quarterly baseline. For Azure.All.md and Azure.Default.md, you can run the Rule docs task in VSCode and that should regenerate these files, ideally do this before you submit the PR.

[ArmaanMcleod]

@BernieWhite Thanks, added a Azure.AKS.Autoscaling rule in the PR. Should be ready for review.