Rattling coming from underneath truck next to driver side by rear tire

[Kixopao]

Hello y’all. I have a 2008 QX56. I get this railing noise coming from underneath periodically. It seems like it’s coming from one of these components. Can someone tell me what they are?
I think I have to order a replacement part.

https://pin.it/1DSmkVHmE

 

[marctronixx]

the photo shows the compressor for the auto leveling system. when you say you get a "rattling noise", does it happen when the car is not moving and running or does it only make a noise when driving? its possible you may hear the compressor kicking in -- what you may call a "rattle", i may call "a compressor running"

a sound clip would be helpful as well.