Azure: Remove AKS vmType

[jackfrancis]

What type of PR is this?

/kind deprecation
/kind documentation
/kind cleanup

What this PR does / why we need it:

This PR removes the obsolete, non-working implementation for manual AKS cluster integration as expressed via the "aks" vmType configuration.

Node autoscaling has long been a first class GA feature of AKS. See:

• https://docs.microsoft.com/azure/aks/autoscaler

Running the Azure cluster-autoscaler provider manually on your cluster is not a supported feature. To aid future maintainability of the project, we're removing these non-working code paths and updating documentation.

Which issue(s) this PR fixes:

Fixes #6190

Special notes for your reviewer:

Does this PR introduce a user-facing change?

Azure: Remove AKS vmType

Additional documentation e.g., KEPs (Kubernetes Enhancement Proposals), usage docs, etc.:

[jackfrancis]

/assign @gandhipr

[jackfrancis]

Validated "vmss" vmType on AKS cluster:

$ git status
On branch azure-aks-vmtype-deprecate
Your branch is up to date with 'origin/azure-aks-vmtype-deprecate'.

nothing to commit, working tree clean
$ TAG=$(git rev-parse --short HEAD) make build
rm -f cluster-autoscaler-amd64
CGO_ENABLED=0 GOOS=linux GOARCH=amd64 go build -o cluster-autoscaler-amd64 --ldflags "-s"
$ REGISTRY=docker.io/jackfrancis TAG=$(git rev-parse --short HEAD) make make-image
docker build --pull \
		-t docker.io/jackfrancis/cluster-autoscaler-amd64:00f9286d1 \
		-f Dockerfile.amd64 .
[+] Building 3.4s (7/7) FINISHED                                                                                                                                                                   docker:desktop-linux
 => [internal] load .dockerignore                                                                                                                                                                                  0.0s
 => => transferring context: 2B                                                                                                                                                                                    0.0s
 => [internal] load build definition from Dockerfile.amd64                                                                                                                                                         0.0s
 => => transferring dockerfile: 866B                                                                                                                                                                               0.0s
 => [internal] load metadata for gcr.io/distroless/static:nonroot-amd64                                                                                                                                            0.4s
 => [internal] load build context                                                                                                                                                                                  1.7s
 => => transferring context: 143.34MB                                                                                                                                                                              1.7s
 => CACHED [1/3] FROM gcr.io/distroless/static:nonroot-amd64@sha256:5f1b35fe0293eebf6e574ee21d43a0ad55beb99e7384427216f5f18eaa9d5077                                                                               0.0s
 => [2/3] COPY cluster-autoscaler-amd64 /cluster-autoscaler                                                                                                                                                        0.7s
 => exporting to image                                                                                                                                                                                             0.6s
 => => exporting layers                                                                                                                                                                                            0.6s
 => => writing image sha256:d0ddf4ffba96368c5748c7669c21e256e1855148ec0ba8ef66125d5f3ad7b957                                                                                                                       0.0s
 => => naming to docker.io/jackfrancis/cluster-autoscaler-amd64:00f9286d1  

What's Next?
  View a summary of image vulnerabilities and recommendations → docker scout quickview
Image 00f9286d1-amd64 completed
$ REGISTRY=docker.io/jackfrancis TAG=$(git rev-parse --short HEAD) make push-image
./push_image.sh docker.io/jackfrancis/cluster-autoscaler-amd64:00f9286d1
About to push image docker.io/jackfrancis/cluster-autoscaler-amd64:00f9286d1
Are you sure? [y/N] y
Error response from daemon: manifest for jackfrancis/cluster-autoscaler-amd64:00f9286d1 not found: manifest unknown: manifest unknown
The push refers to repository [docker.io/jackfrancis/cluster-autoscaler-amd64]
e918121e441b: Pushed 
4cb10dd2545b: Layer already exists 
d2d7ec0f6756: Layer already exists 
1a73b54f556b: Layer already exists 
e624a5370eca: Layer already exists 
d52f02c6501c: Layer already exists 
ff5700ec5418: Layer already exists 
7bea6b893187: Layer already exists 
6fbdf253bbc2: Layer already exists 
54ad2ec71039: Layer already exists 
00f9286d1: digest: sha256:f89fac8e2c68f579cd6577d5e74ebb459fcb077673f370909b5fdb7dac575126 size: 2402
$ helm install cluster-autoscaler cluster-autoscaler --repo https://kubernetes.github.io/autoscaler --set cloudProvider=azure --set autoscalingGroups[0].name=aks-nodepool2-26139306-vmss,autoscalingGroups[0].maxSize=100,autoscalingGroups[0].minSize=0 --set azureClientID=$TEST_AZURE_SP_ID --set azureClientSecret=$TEST_AZURE_SP_PW --set azureSubscriptionID=$TEST_AZURE_SUB_ID --set azureTenantID=$TEST_AZURE_TENANT_ID --set azureResourceGroup=MC_francis-aks-test_francis-aks-test_eastus --set azureVMType=vmss --set image.repository=docker.io/jackfrancis/cluster-autoscaler-amd64 --set image.tag=00f9286d1
NAME: cluster-autoscaler
LAST DEPLOYED: Wed Oct 11 15:20:32 2023
NAMESPACE: default
STATUS: deployed
REVISION: 1
TEST SUITE: None
NOTES:
To verify that cluster-autoscaler has started, run:

  kubectl --namespace=default get pods -l "app.kubernetes.io/name=azure-cluster-autoscaler,app.kubernetes.io/instance=cluster-autoscaler"
$ k apply -f https://k8s.io/examples/application/php-apache.yaml
deployment.apps/php-apache created
service/php-apache created

Validated scale in to zero:

$ k scale deployment/php-apache --replicas=0
deployment.apps/php-apache scaled
$ k get nodes -o wide | grep aks-nodepool2 | wc -l && sleep 600 && k get nodes -o wide | grep aks-nodepool2 | wc -l
       4
       0

Validated scale out from zero:

$ k scale deployment/php-apache --replicas=1000
deployment.apps/php-apache scaled
$ k get nodes -o wide | grep aks-nodepool2 | wc -l && sleep 600 && k get nodes -o wide | grep aks-nodepool2 | wc -l
       0
     100

[jackfrancis]

@gjtempleton am I doing the right or wrong thing updating the helm chart (and bumping the version) in this PR? Or would we prefer to separate the helm changes from the underlying code changes?

[jackfrancis]

/hold

while I work on a possible fix

[jackfrancis]

Current plan is to move forward w/ this.

cc @prachirp @tallaxes

I shared a PSA about this in SIG Autoscaling weekly meeting today. I'll wait a week or so to allow for public feedback, then I'll press for a final review and merge.

[tallaxes]

/approve

[jackfrancis]

@gjtempleton is this PR ready to merge in terms of helm chart updates?

Chart changes + new minor version change are in this PR.

Thanks!

[jackfrancis]

/hold cancel

[tallaxes]

/lgtm

[jackfrancis]

/assign @gjtempleton

[jackfrancis]

/approve

[Shubham82]

@gjtempleton could you please approve this PR, so that it will merge?
Thanks!

[gjtempleton]

Looks good to me from the chart side.

thanks!
/approve

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: Bryce-Soghigian, gjtempleton, jackfrancis, tallaxes

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Needs approval from an approver in each of these files:

• charts/OWNERS [gjtempleton]
• cluster-autoscaler/cloudprovider/azure/OWNERS [gjtempleton,jackfrancis,tallaxes]

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