The AdoptedResource CRD does not work for ApplicationAutoscaling Service Controller

[mbaijal]

Describe the bug
The AdoptedResource CRD does not work for ApplicationAutoscaling Service Controller since the ScalingPolicy and ScalableTarget Describe APIs require more than one field to work.

Steps to reproduce

1. Create an endpoint in SageMaker and enable applicationAutoscaling using the AWS Console.
2. Check using awscli to ensure that the ScalingPolicy resource exists aws application-autoscaling describe-scaling-policies --service-namespace SageMaker --region us-west-2.
3. Update ApplicationAutoscaling to v0.1.1 runtime and latest code-gen. Verify that you have the AdoptedResource CRD.
4. Now try to adopt the resource into Kubernetes using a spec file as follows -

apiVersion: services.k8s.aws/v1alpha1
kind: AdoptedResource
metadata:
  name: adoptedscalingpolicy
spec:
  aws:
    nameOrID: "endpoint/ep-name/variant/AllTraffic"
  kubernetes:
    group: applicationautoscaling.services.k8s.aws
    kind: ScalingPolicy
    metadata:
      name: adopted_scaling_policy

5. check that the resource was adopted using kubectl get scalingpolicies.applicationautoscaling.services.k8s.aws

Expected outcome
Resource should have been adopted into k8s

Actual Outcome
The following error in the pod logs -

2021-05-11T10:24:55.574Z	ERROR	controller-runtime.controller	Reconciler error	{"controller": "adoptedresource", "request": "default/adoptedscalingpolicy", "error": "InvalidParameter: 1 validation error(s) found.\n- missing required field, DescribeScalingPoliciesInput.ServiceNamespace.\n"}

Environment
Tested using a Kind Cluster

• Kubernetes version: 16.*
• Using EKS (yes/no), if so version?: no
• AWS service targeted (S3, RDS, etc.): ApplicationAutoscaling

[jaypipes]

How about adding another field to ackcorev1alpha1.AWSIdentifiers called AdditionalKeys of type map[string]string and those additional keys can be processed by the AWSResource.SetIdentifiers() method to set additional key fields as needed.

In the example here, the adopted resource CR would look like this instead:

apiVersion: services.k8s.aws/v1alpha1
kind: AdoptedResource
metadata:
  name: adoptedscalingpolicy
spec:
  aws:
    nameOrID: "endpoint/ep-name/variant/AllTraffic"
    additionalKeys:
      serviceNamespace: "SageMaker"
  kubernetes:
    group: applicationautoscaling.services.k8s.aws
    kind: ScalingPolicy
    metadata:
      name: adopted_scaling_policy

and the applicationautoscaling-controller's pkg/resource/scaling_policy/resource.SetIdentifiers() method would be changed to account for the additionalKeys fields and values...

The template code that generates SetIdentifier would obviously need a little updating to loop over the additionalKeys:

https://github.com/aws-controllers-k8s/code-generator/blob/4635e5659bb367f2e34c3b029a4fa56f07b851fc/templates/pkg/resource/resource.go.tpl#L64-L76

but that shouldn't be too difficult to do.

[RedbackThomson]

As per the suggestion above, I have included the additionalKeys map as part of AWSIdentifiers.

Runtime PR: aws-controllers-k8s/runtime#13
Code-Generator PR: aws-controllers-k8s/code-generator#62

An example of it working for this use case:

I put a new scaling policy using the AWS CLI:

aws application-autoscaling put-scaling-policy --policy-name test-policy --service-namespace sagemaker --resource-id endpoint/xgboost-endpoint-znwbi73nyztvdah/variant/variant-1 --scalable-dimension sagemaker:variant:DesiredInstanceCount --policy-type TargetTrackingScaling --target-tracking-scaling-policy-configuration file://example-scaling-policy.json

Then attempted to adopt the resulting scaling policy given the return ARN and serviceNamespace additional key:

apiVersion: services.k8s.aws/v1alpha1
kind: AdoptedResource
metadata:
  name: adopt-xgboost-scaling-policy
spec:
  aws:
    arn: arn:aws:autoscaling:us-west-2:<redacted>:scalingPolicy:d908645f-4669-4db7-8c7e716484b67601:resource/sagemaker/endpoint/xgboost-endpoint-znwbi73nyztvdah/variant/variant-1:policyName/test-policy
    additionalKeys:
      serviceNamespace: sagemaker
  kubernetes:
    group: applicationautoscaling.services.k8s.aws
    kind: ScalingPolicy

It successfully reproduced the spec:

Name:         adopt-xgboost-scaling-policy
Namespace:    default
Labels:       <none>
Annotations:  services.k8s.aws/adopted: true
API Version:  applicationautoscaling.services.k8s.aws/v1alpha1
Kind:         ScalingPolicy
Metadata:
  Creation Timestamp:  2021-05-12T23:06:14Z
  Finalizers:
    finalizers.applicationautoscaling.services.k8s.aws/ScalingPolicy
  Generation:        1
  Resource Version:  1138911
  Self Link:         /apis/applicationautoscaling.services.k8s.aws/v1alpha1/namespaces/default/scalingpolicies/adopt-xgboost-scaling-policy
  UID:               007b3a31-040d-4e5f-b7fd-449d85ad150e
Spec:
  Policy Name:         test-policy
  Policy Type:         TargetTrackingScaling
  Resource ID:         endpoint/xgboost-endpoint-znwbi73nyztvdah/variant/variant-1
  Scalable Dimension:  sagemaker:variant:DesiredInstanceCount
  Service Namespace:   sagemaker
  Target Tracking Scaling Policy Configuration:
    Predefined Metric Specification:
      Predefined Metric Type:  SageMakerVariantInvocationsPerInstance
    Target Value:              70
Status:
  Ack Resource Metadata:
    Owner Account ID:  <redacted>
  Alarms:
    Alarm ARN:   arn:aws:cloudwatch:us-west-2:<redacted>:alarm:TargetTracking-endpoint/xgboost-endpoint-znwbi73nyztvdah/variant/variant-1-AlarmHigh-ab739cb9-0ef3-4bd5-8d8e-c2f13dfe8dd5
    Alarm Name:  TargetTracking-endpoint/xgboost-endpoint-znwbi73nyztvdah/variant/variant-1-AlarmHigh-ab739cb9-0ef3-4bd5-8d8e-c2f13dfe8dd5
    Alarm ARN:   arn:aws:cloudwatch:us-west-2:<redacted>:alarm:TargetTracking-endpoint/xgboost-endpoint-znwbi73nyztvdah/variant/variant-1-AlarmLow-e8f129ef-7b1e-44ed-8ef4-54fe12d3b481
    Alarm Name:  TargetTracking-endpoint/xgboost-endpoint-znwbi73nyztvdah/variant/variant-1-AlarmLow-e8f129ef-7b1e-44ed-8ef4-54fe12d3b481
  Conditions:
  Policy ARN:  arn:aws:autoscaling:us-west-2:<redacted>:scalingPolicy:d908645f-4669-4db7-8c7e-716484b67601:resource/sagemaker/endpoint/xgboost-endpoint-znwbi73nyztvdah/variant/variant-1:policyName/test-policy
Events:        <none>