Mount pergola post at an angle
At the ground, you're mostly concerned with keeping the posts located. You don't want bumps to slide them around. A simple steel pin or bolt in the concrete is adequate. If you like, use a short stack of washers to keep the wood (mostly) out of contact with the concrete to improve longevity.

At the top, I'd use 1/2" lag screws, countersunk and piloted. Two at each joint and penetrating 4-5" into the posts should do. You'll want to cap or plug the bores to prevent water accumulation and rot. 

All hardware should be stainless or galvanized, in case it's not obvious.