We have no commitment to spend 2% of GNP. Both Harper and  Trudeau told NATO that.  We are not breaking our work, we're sticking to it. 
Canada is sovereign. If we say we aren't spending X there is no one to tell us to. 
Real dollars are what count. In actual money DND's budget is about 16th in the world and 6th in NATO. 
The goal NATO wants for defence spending not defence department spending. VAC, CSIS, part of PW, the RCMP and CG, anti-terror effort by other police forces and governments as well as all the interest paid on the national debt that went to defence spending. We might actually be over 2%.
NATO is a one way alliance. North Americans promise to rescue Europeans. Anything we chip in is a gift and the Europeans should simply be grateful. The "2%" goal is just a way for NATO to keep it's rice bowl filled and has nothing to do with our security- NATO outnumbers Russia 6-1 and over 20-1 in industrial capacity without counting allies such as Australia or Japan.