It seems to be accepted that Putin wants a war in Ukraine, and in absence of any other strong allied militaries around, the only way to get that is attack by Russia itself.
The military conflict in Ukraine is now 8 years old: for 7 of which, it is a frozen conflict where there's a stable border between Ukraine and what's seceded off it. Shellings seem to happen weekly with skirmishes once a few months. During these 7 years, no large-scale war took place.
So the question is, what's different now? Are there any particular reasons why Putin wants to defrost this conflict just now? I think some documents were supposedly leaked in late 2021, did they contain any 'motivation' section? Or maybe there are some logical reasons why it should happen this year any more than the previous one or the year after?