Discussion about Scheduling changes, and detecting the implication of changes.
This is somewhat fuzzy, but there are changes we'd like to apply immediately, while other changes should only be applied when it's "safe" (where the definition of "safe" may be different for different hosts). E.g. we only run spma right before a reboot, because installing/removing/upgrading packages in general is just too dangerous when the system is in production. A separate, but related issue is how to detect the impact of a configuration change: does activating the new profile require a reboot, or even a full rebuild (e.g. when the partitioning layout changes)?