Comment 28 for bug 1233466

I fail to come up with a use-case that just wants to add CPU/RAM without onlining it sooner or later. For virtual environments, you add CPU/RAM to use it and therefore want to online it once it appears. In a cloud environment (like ProfitBricks), it makes no sense to add CPU/RAM without using it, because you have to pay for it.

Hot-add is supposed to work on recent kernels (>= 3.10). Kernel 3.2 had an issue, but I can't remember if adding CPU/RAM or onlining it causes the issue.

I would be happy to unconditionally turning hot-add on and SRU the udev rule back to Ubuntu 14.04.