Important: Mandatory flag for admin cluster upgrades

Important: Mandatory flag for admin cluster upgrades

If an update or upgrade to advanced admin clusters fails in versions 1.32 and newer, don't delete the external bootstrap cluster from the workstation. The bootstrap cluster contains required information about states that you need to resume the update or upgrade. If an update or upgrade to admin clusters fails, and you re-run gkectl upgrade admin, you must add the flag --reuse-bootstrap-cluster or you can lose critical data.