Can someone provide me with doc's or knowledge of the steps needed to upgrade from 3.2.1 to 4+. I have 7 node's that need to upgrade and I need to know the good and bad.
Do all have to be upgraded at the same time?
How long does an upgrade typically take?
Can it be done remotely or not recommended? etc.
I know this is kind of open ended but any and all info is appreciated. Thanks