I havent used kubernetes as well. Cant see an advantage, maybe later some other day it will be eye opening.
How do you track/monitor you application? I start my app with xms4g and xmx4g and periodically check the usage if Garbage Collection is able to clean up the heap. So i would be worried if the heap stays at 3gb for example and it will not shrink.
I would really appreciate if there would be a reliable way to meassure the consumption of vaadin. But its not that easy see here Vaadin Session Size Tracking - #9 by Tatu2
Thats the only reason which hold me back to use vaadin in more bigger projects. I can not really predict how much it will use/need etc.