It needs a diplomatic solution where Putin doesn't get humiliated, even though he deserves it hugely, and people living in former Ukraine regions get to move into real Russian territory if that's what they want with the annexed areas, including Crimea are returned to Ukraine. Unlikely I know.
This, of course, assumes that Vlad is prepared to accept a diplomatic outcome. Personally, I don't think he is.
He has got where he is by intimidation and force and I whilst China/India (in particular) stand on the sidelines, he thinks that the West won't have the stomach for a drawn out conflict.