Upgrading the cluster recently has brought nothing but trouble, with seeming conflicts between python-devel and python. Hacking and slashing through this on the UI I have now realised why. The conflict comes not from the x86_64 python RPM, but from the extra i386 python RPM we install to provide a 32bt python (needed by LCG modules like the python lfc plugin).
To avoid having to present the whole i386 repo to YUM, we'd picked out a few choice i386 packages and dropped them into the local cluster repo. However, in the meantime the i386 python had been updated and our version remained old and stale - causing the unsatisfiable dependency.
I have now updated and rebuilt the repo and things seem to upgrade smoothly at last.
However, roll on ye native 64bit middleware. This is too much of a pain at times...