🐛 clusterctl: validate no objects exist from CRDs before deleting them

[chrischdi]

What this PR does / why we need it:

Adds a safeguard when clusterctl delete --include-crd is executed to not do anything if there are still Custom Resources for a CRD.

Which issue(s) this PR fixes (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close the issue(s) when PR gets merged):
Fixes #9732

/area clusterctl

[sbueringer]

Just a few nits

[chrischdi]

/retest

[k8s-ci-robot]

@chrischdi: The following test failed, say /retest to rerun all failed tests or /retest-required to rerun all mandatory failed tests:

Test name	Commit	Details	Required	Rerun command
pull-cluster-api-apidiff-main	b8f1cc0	link	false	/test pull-cluster-api-apidiff-main

Full PR test history. Your PR dashboard. Please help us cut down on flakes by linking to an open issue when you hit one in your PR.

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[sbueringer]

Thx!

/lgtm
/approve

[k8s-ci-robot]

LGTM label has been added.

Git tree hash: a733c0403a85c6734eacbb95652ec2efef2fd75a

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: sbueringer

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• cmd/clusterctl/OWNERS [sbueringer]

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[sbueringer]

If possible I would like to cherry-pick this into release-1.6 and release-1.5. I think it's currently not intended that clusterctl delete --include-crd triggers deletion of all CRs in a mgmt cluster. It can have catastrophic consequences and also our deletion reconciliations are not designed for all objects being deleted at the same time.

@CecileRobertMichon @enxebre @vincepri @fabriziopandini Fine for you if we cherry-pick?

[sbueringer]

/cherry-pick release-1.6

[sbueringer]

/cherry-pick release-1.5

[k8s-infra-cherrypick-robot]

@sbueringer: #9808 failed to apply on top of branch "release-1.5":

Applying: clusterctl: validate no objects exist from CRDs before deleting them
Using index info to reconstruct a base tree...
M	cmd/clusterctl/client/cluster/components.go
M	cmd/clusterctl/client/cluster/components_test.go
M	cmd/clusterctl/client/delete.go
M	cmd/clusterctl/client/delete_test.go
Falling back to patching base and 3-way merge...
Auto-merging cmd/clusterctl/client/delete_test.go
Auto-merging cmd/clusterctl/client/delete.go
Auto-merging cmd/clusterctl/client/cluster/components_test.go
Auto-merging cmd/clusterctl/client/cluster/components.go
CONFLICT (content): Merge conflict in cmd/clusterctl/client/cluster/components.go
error: Failed to merge in the changes.
hint: Use 'git am --show-current-patch=diff' to see the failed patch
Patch failed at 0001 clusterctl: validate no objects exist from CRDs before deleting them
When you have resolved this problem, run "git am --continue".
If you prefer to skip this patch, run "git am --skip" instead.
To restore the original branch and stop patching, run "git am --abort".

In response to this:

/cherry-pick release-1.5

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.

[k8s-infra-cherrypick-robot]

@sbueringer: new pull request created: #9834

In response to this:

/cherry-pick release-1.6

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