Warnings for blocking PodDisruptionBudgets

1. Proposed title of this feature request

Warnings for blocking PodDisruptionBudgets

2. What is the nature and description of the request?

With RFE-2261 we introduced the new view for PodDisruptionBudgets which was highly appreciated by customers (what a great feature!).

Now that PodDisruptionBudgets are shown in the console we should show a warning to the user if a certain PodDisruptionBudget is blocking a Node Drain.

• For example, often customers specify "minAvailable" equal to the amount of replicas in a Deployment. This means that no Pods can safely be deleted without violating the PodDisruptionBudget (thus blocking node drain operations for example).
• Another example is setting "maxUnavailable" of 0% or 0 or a "minAvailable" of 100% or equal to the number of replicas

We already describe this in the documentation, however this is often ignored: https://docs.openshift.com/container-platform/4.9/nodes/pods/nodes-pods-configuring.html#nodes-pods-configuring-pod-distruption-about_nodes-pods-configuring
The proposal would be to add a warning (yellow triangle or some info text) when a PodDisruptionBudget has such a configuration to make developers aware of this problematic configuration.

3. Why does the customer need this? (List the business requirements here)

This leads to Worker Nodes not being able to be drained (see also RFE-1244, OCSBZM-1109), which interrupts cluster operations and upgrades.

4. List any affected packages or components.

Developer Console
Web Console