uninitialized taint should always be dropped

[ykakarap]

Detailed Description

#7993 introduced the node.cluster.x-k8s.io/uninitialized:NoSchedule taint. This taint is applied by default to the nodes when CAPBK is used as the bootstrap provider. CAPI drops this taint from the nodes after the nodes are initialized (labels are synced).

This issue is to audit and ensure that the node is dropped by CAPI when using any of the Machine/MachinePool solutions.

• Machines
• MachinePoll
• MachinePool Machines

[A clear and concise description of what you want to happen.]

Anything else you would like to add:

More context on the taint: The taint was introduced to solve the delay problem when syncing label to nodes to avoid unnecessarily scheduling workloads on wrong nodes.
Part of proposal: Label Sync Between Machines and underlying Kubernetes Nodes

/kind feature

[sbueringer]

@ykakarap Sorry I think my comment on the PR was a bit misleading. I think we're probably fine with the taint (as you already implemented that in #7993), although it doesn't hurt to double check.

I was referring to in-place propagation in general. I wonder if we want to have in-place propagation for MachinePool as well, especially once the MachinePool Machines are introduced, but maybe even for the objects "below" MachinePool we have today.

Or maybe the concept doesn't make sense for MachinePools not sure.

[sbueringer]

^^ @CecileRobertMichon

[fabriziopandini]

/triage accepted
@sbueringer please check we should rename this issue to make it more clear what we want to achieve

[fabriziopandini]

/help

[k8s-ci-robot]

@fabriziopandini:
This request has been marked as needing help from a contributor.

Guidelines

Please ensure that the issue body includes answers to the following questions:

• Why are we solving this issue?
• To address this issue, are there any code changes? If there are code changes, what needs to be done in the code and what places can the assignee treat as reference points?
• Does this issue have zero to low barrier of entry?
• How can the assignee reach out to you for help?

For more details on the requirements of such an issue, please see here and ensure that they are met.

If this request no longer meets these requirements, the label can be removed
by commenting with the /remove-help command.

In response to this:

/help

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository.

[sbueringer]

I would like to get feedback to my comment from @ykakarap before retitling/rewriting the issue

[ykakarap]

I am +1 to exploring in-place propagation support in MachinePools and MachinePool Machines (when it is introduced).

I am not aware of the full details of how MachinePool Machines is going to work but I would like to capture that once MachinePool Machines are introduces we ensure that they too drop the uninitialized taint. As long as we capture that after rewriting I am +1 to renaming/rewriting.

[CecileRobertMichon]

@ykakarap PR for MachinePool Machines is ready for review: #7938 and proposal with more detail can be found here: https://github.com/kubernetes-sigs/cluster-api/blob/main/docs/proposals/20220209-machinepool-machines.md