Currently it seems that Juju is not able to start / stop existing units. Say I have a very large application that takes some time to push up a new machine, I would likely want to scale up machines in advance and then only bring them up when needed.
Currently add-unit adds new units. Is it likely juju will be extended to allow to provision units in advance and then when scaling up, use those units instead of creating totally new servers?
Cloud servers often cost money when running - thus it seems that this would make sense to be able to just stop/start instead of only add/remove.