Expose a new Setting in Rancher UI: k3s-based-upgrader-uninstall-concurrency

[jiaqiluo]

As part of the effort to deprecate the legacy rancher-k3s-upgrade system chart, a new setting k3s-based-upgrader-uninstall-concurrency is being introduced to manage the cadence of uninstalling that app in downstream imported RKE2/K3s clusters. It is necessary to expose this setting to users, allowing them to customize it according to their needs.

The new setting will be displayed in the Global Settings -> Settings page, with the following characteristics:

• Name: k3s-based-upgrader-uninstall-concurrency
• Description: Defines the maximum number of clusters in which Rancher can concurrently uninstall the legacy rancher-k3s-upgrader or rancher-rke2-upgrader app from imported K3s or RKE2 clusters.
• Default: 5

Related backend issue: rancher/rancher#42448

Please check the RFC for more information.

SURE-9046

[richard-cox]

More info in JIRA, but blocked on creation of setting

[richard-cox]

Removed assignments, anyone can pick this up once setting available

[jiaqiluo]

The backend PR has been merged, and the changes are now available in the latest docker.io/rancher/rancher:head image. This should no longer be a blocker for the UI.

cc @richard-cox

[gaktive]

The theory is that the Steve API should report the min/max values. However, @kwwii may have some design questions, especially if the Global Settings page is the right home.

@richard-cox can you confirm that this belongs on Global Settings? and are there any other limitations for UI that need to factor in that weren't documented?

[gaktive]

Feature complete comes up very soon here so if this is needed for 2.10.0, we can step over a bit unless it's super clear to others closer to the ticket may indicate how quick it'll be.

[richard-cox]

This is a setting to assist a short term feature applicable to bulk updates to downstream clusters that have had their kube version bumped and was discussed in the RFC. I would vote we add this to general settings, but remove it after 2.12 (and update docs)