feat(controller): add paused resource handling and update manager setup

[jds9090]

Closes #155

[prometherion]

I'm not 💯 sure pause should block deletion: AFAIK there's the Kubernetes convention where deletion is blocked only by finalizers.

The main problem I see here is the following: imagine a Kamaji Control Plane paused in a Namespace, and the parent Namespace is deleted. With the proposed code, when this condition happen, the Namespace deletion will stuck untill the Kubernetes administrator removes the paused annotation (if he knows the knob).

Despite this, it would be better ask to CAPI maintainers if paused objects should block deletion or not, and according to their answers evaluate if we need further code changes.

However, I'm totally ok with the feature changes will introduce, thanks!

[jds9090]

I'm not 💯 sure pause should block deletion: AFAIK there's the Kubernetes convention where deletion is blocked only by finalizers.

The main problem I see here is the following: imagine a Kamaji Control Plane paused in a Namespace, and the parent Namespace is deleted. With the proposed code, when this condition happen, the Namespace deletion will stuck untill the Kubernetes administrator removes the paused annotation (if he knows the knob).

Despite this, it would be better ask to CAPI maintainers if paused objects should block deletion or not, and according to their answers evaluate if we need further code changes.

However, I'm totally ok with the feature changes will introduce, thanks!

Thank you for the insightful feedback! I'd like to provide some clarification regarding the use of the paused annotation in the current implementation.

The behavior implemented in this PR is consistent with the existing behavior of other CAPI resources, such as:

• kubeadmcontrolplane : https://github.com/kubernetes-sigs/cluster-api/blob/3cce0d973682f11ab0f0ba1c2522eba66dac2d91/controlplane/kubeadm/internal/controllers/controller.go#L164
• machineset : https://github.com/kubernetes-sigs/cluster-api/blob/3cce0d973682f11ab0f0ba1c2522eba66dac2d91/internal/controllers/machineset/machineset_controller.go#L166
• machine : https://github.com/kubernetes-sigs/cluster-api/blob/3cce0d973682f11ab0f0ba1c2522eba66dac2d91/internal/controllers/machine/machine_controller.go#L189