- it's best to replace nodes, don't do apt/yum upgrades.
- both would work, but VM replacment forces me to think of it as immutable and prevents making pets
- if you don't want to update join scripts for manager IP's, then do something like Elastic IP's so manager IP's won't change.
Lets assume you have 3 managers and 3 workers on 17.06 and you want to update to 17.12
- managers: m1, m2, m3