RFE: Adding a new CRD for post-cluster-creation-apply YAMLs

[sedefsavas]

Goals
To enable having a mechanism to automatically apply a set of yamls post-cluster-creation, we need a CRD to hold the list of yamls and to keep track of which clusters those yams are applied to. This is a follow-up enhancement to achieve this issue: #1910

User Story
As a user/operator, I would like to determine a set of yamls (e.g., CNI/CSI plugins) that I want to automatically apply to certain clusters post-creation.

Detailed Description
Details can be found: https://docs.google.com/document/d/1lWLGN66roMjXL49gKO6Dhwe7yzCnvgrCtjR9mu4rvPc/edit?usp=sharing

POC: sedefsavas#3

/kind proposal

[vincepri]

@sedefsavas do you want to close #1910 and keep this one or merge the content you have here?

[ncdc]

@sedefsavas which option do you prefer (hard to tell what the thumbs-up is for 😄)?

[sedefsavas]

Closing #1910, most of the discussions there do not apply anymore as we propose a new CRD here. Copying some concerns discussed there that still apply (we also have them in the design doc

1- Do we keep the thunks to be applied in secrets or configmaps?
2- Should the thunks be applied at each reconcile or only once?
3- What should be the name of this CRD?
4- Do we reapply the thunks after cluster upgrade or not? We can specify create and upgrade flags for thunks that describes when the thunk will be applied.

[vincepri]

Another use case we might want to think about:

To improve the user experience, infrastructure providers could ship with a default storage class which should be applied after the cluster is initialized

[vincepri]

As per April 27th 2020 community guidelines, this project follows the process outlined in https://github.com/kubernetes-sigs/cluster-api/blob/master/CONTRIBUTING.md#proposal-process-caep for large features or changes.

Following those guidelines, I'll go ahead and close this issue for now and defer to contributors interested in pushing the proposal forward to open a collaborative document proposal instead, and follow the process as described.

/close

[k8s-ci-robot]

@vincepri: Closing this issue.

In response to this:

As per April 27th 2020 community guidelines, this project follows the process outlined in https://github.com/kubernetes-sigs/cluster-api/blob/master/CONTRIBUTING.md#proposal-process-caep for large features or changes.

Following those guidelines, I'll go ahead and close this issue for now and defer to contributors interested in pushing the proposal forward to open a collaborative document proposal instead, and follow the process as described.

/close

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