Exactly. Joint military exercises then Kazakhstan will find itself held hostage within its own borders.I think the Kazak leadership is already a Putin ally, but I wouldn't be surprised to see a future "closer partnership" with Russia, just like Belarus now.
I don't know much about Kazakhstan but I don’t think they have a clue about democracy so the people aren't likely to cause too much of a problem, unlike those in Belarus who get democracy filtering over the borders with Ukraine, Poland and the three Baltic republics.