Why do you think he is on the move, increase its resources base? Ukraine provides 12% of the global wheat and other agriculture products and war is always good for birth rates eventually.
Putin's first and foremost a gangster. Always has been. Unfortunately when you structure your government on exactly the same lines as a Mafia family or Mexican drug cartel there's always the risk of someone kicking the chair out from under you. He usually handles those threats by cutting off big slices of the pie to his associates in the form of lucrative government contracts, political influence and occasionally just cold, hard cash.
The Russian people however are a lot harder to placate and can be just as much of a risk to his throne so he goes for big distractions. He's aligned his government with the orthodox church and deliberately ensured that state media is of a paranoid right-wing bent while deliberately marginalising more widely or better informed groups such as students and the LGBTQI communities. With the nationalistic groundwork in place, it makes it much easier for him to cement his position as a strong-man by sending the Russian army over the border into weaker, neighbour states for an easy victory both militarily and in the public eye. A limited incursion into Ukraine will be a popular move amongst the nationalists, it'll provide a big spending splurge for his cronies who hold military contracts and the fact that he can do this credible little opposition internationally means that if he does decide to settle things diplomatically, he'll be in a much better position for bargaining and can maybe even use it to leverage more lucrative gains and/or the dialling back of existing sanctions, etc.
On a personal note about 10 years back I travelled across Russia on the Trans-Siberian railway. During the journey I remember chatting with a lad in his 20's who like most Russian men had undergone national service in the army (i.e conscription). He was involved in the invasion of Georgia but to hear the way he'd described it, Russia were entirely the innocent party and it was all just a response to Georgian aggression. It was weird as the lad otherwise seemed like a fairly well informed, normal bloke. His English was quite good - far better than most Russians - so he wasn't your typical nationalist with zero experience with other countries or international media. In fact I got the impression that he was well aware of how the whole invasion was portrayed in the international press and he just wanted to assure me that Russia weren't the bad guys. I guess that goes to show how well Putin has been at playing the victim card.
Incidentally, if anyone's after some good reading on the subject that's a bit easier to digest than your average university textbook, I recommend former chess world champion Garry Kasparov's 'Winter Is Coming'. It might have been published 7 years ago but it still holds true to this day - if anything it does a good job of predicting what has happened with Russia in the years since...
