On Sat, Dec 15, 2012 at 12:43 PM, Koushik Das <koushik....@citrix.com> wrote: > Currently CS supports changing CPU and RAM for stopped VM. This is achieved > by changing compute offering of the VM (with new CPU and RAM values) and then > starting it. I am planning to extend the same for running VM as well. > Initially planning to do it for Vmware where CPU and RAM can be dynamically > increased. Support of other HVs can also be added if they support increasing > CPU/RAM. > > Assuming that in the updated compute offering only CPU and RAM has changed, > the deployment planner can either select the same host in which case the > values are dynamically scaled up OR a different one in which case the > operation fails. In future if there is support for live migration (provided > HV supports it) then another option in the latter case could be to migrate > the VM first and then scale it up. > > I will start working on the FS and share it out sometime next week.
Thanks for starting this conversation early in the process, Koushik. I'd want to make just 'how much' resources can be scaled up a configuration option. Is 2x reasonable? probably, is 50x reasonable, probably not. Or actually - thinking about this - perhaps this becomes part of the service offering. You can start at 2cores/4gb but have a place to scale up to without restart, but you know from the outset exactly how far that is. Actually - since you can't scale it back down, that makes even more sense to me. (I know you can't scale back down in KVM, not so sure about VMware) I am worried about the effect of this on usage statistics, but still sounds very useful. Maybe you solve the allocation problem by actually allocating for the max allocatable - of course if that goes into usage metrics, and then on to billing perhaps it isn't as attractive. --David
