Jacks: No indication about what "kind of name" goes into the "Disk Image" name-entry field
The Jacks interface does not make it clear that when one chooses "Other..." for a node's disk image, the text in the box is supposed to be a URN. See pic below.
Consider a user of the Emulab portal. It is reasonable to think that a user might put a Emulab-style image name in that box (e.g., "FBSD103-64-STD"), and in fact, if one does this there is no error message. The user doesn't get an error until he or she tries to create an experiment, at which point he or she might be told:
This profile will not work on any clusters. Please check your profile or parameters for errors. If you are sure they are correct, you can report the problem to support@cloudlab.us and make sure to link to the problematic profile.