Put recommendation result into target's annotation

[qmhu]

Describe the feature

currently the recommendation result is present on recommendation.status, we can also put it into target's annotation.
this feature should be an option in recommendation's spec.

[mfanjie]

can you elaborate more about what's the reason of putting the recommendation to annotation?

[qmhu]

Currently we put the recommendation result in recommendation.status like this:

apiVersion: analysis.crane.io/v1alpha1
kind: Analytics
metadata:
  name: craned-hpa
  namespace: crane-system
spec:
  completionStrategy:
    completionStrategyType: Periodical
    periodSeconds: 86400
  resourceSelectors:
  - apiVersion: apps/v1
    kind: Deployment
    labelSelector: {}
    name: craned
  type: HPA
status:
  lastSuccessfulTime: "2022-01-13T07:26:18Z"
  recommendations:
  - apiVersion: analysis.crane.io/v1alpha1
    kind: Recommendation
    name: craned-hpa-hpa-2f22w
    namespace: crane-system
    uid: 397733ee-986a-4630-af75-736d2b58bfac

We can also put the result into target's annotation, then user can view the result from target's annotation, it's convenient for dashboard requirements and so on.

apiVersion: apps/v1
kind: Deployment
metadata:
  name: php-apache
  annotations:
    analysis.crane.io/recommend-hpa: {json encoded string}

[mfanjie]

firstly I think the reference is defined in Analytics and Recommendation, so if dashboard need the relation, it can get directly.
secondly, if we really want a reversed annotation in deployment, the recommendation name is enough already, right?

[qmhu]

firstly I think the reference is defined in Analytics and Recommendation, so if dashboard need the relation, it can get directly. secondly, if we really want a reversed annotation in deployment, the recommendation name is enough already, right?

If customer have a deployment list and want to show the recommendation about it, if we only provide name, then they need to fetch N times to get all deployment's recommendation.

[qmhu]

Api design :
gocrane/api#40

[qmhu]

implement by #192