Hi Nadine,

What matters for CRA is your physical residence along with the time spent in there. If you live in Doha for more than 6 months (180 days I think), you will not be taxed in Canada but in Qatar... so no taxes for you!
I have some friends in that situation. They live in the UAE, Europe all year long, they don't pays taxes in Canada. I'm in Ottawa and I have many friends working for CRA (some in the tax evasion department).

I'm pretty sure the same rule applies for European countries. Most countries have agreements to that effect.

You can keep your house, it's not an issue.

If you have other questions, don't hesitate.