think a lot depends on what you are trying to accomplish.  Are you wanting a weather resistant shop or just a roof to pull under?  I've no experience but I've heard using a hoop building or a carport between the containers is OK if you don't mind water getting in the middle.Here's one on Amazon.

My son in law sells carports.  I don't think he's sold any but we've discussed it. You could space the carports so there is a carport between them  I think you'd want it tall enough to put a rain gutter on the direct the water away.  But that still doesn't do much for the rain on top of the containers

If you're wanting something a bit more the best route is put it the roof over the containers.  You could even build it tall enough to have storage space on top of the containers.  Here's something I stumbled across showing that idea
edit: I tried posting the photos but it got too large.  Click here to see