Image specification on multi-architecture clusters (e.g., Utah Cloudlab)
As we are not far from having both x86 and ARM based machines in the same cluster, we should decide on how "convenient" we want to make it for users to configure cross-architecture experiments.
The issue is whether users should be able to just say that they want nodes running "Ubuntu 14" and have that automatically mapped to the correct image for the architecture of the nodes chosen. Right now you either 1) don't specify an OS so that you could get any node type along with its default OS image, or 2) decide in advance which nodes are of which architecture by explicitly specifying either UBUNTU14-64-ARM or UBUNTU14-64-STD as the node OS.
Is this good enough?
If the answer is "no", then standard images are only the first problem. Ultimately people will want to customize their images and we will have to have a way for them to snapshot the same custom images on the two different architectures and have those images be associated as being "the same" image. And whatever we do won't prevent confusion for people who distribute their own packages at swapin time or run software directly out of their NFS shared directories.
Of course this problem exists today in the context of cross-site experiments, but I would argue that those will never be as common.