Manila needs a grouping construct that, like shares, is a 1st-class
atomic data type. Our experience with CGs has demonstrated the
complexity of adding a grouping capability, yet there are other use
cases such as migration, replication, and backup in which some
storage controllers could only offer such features on share groups.
CGs also highlighted the poor optics of an advanced feature with
comparatively little potential for vendor support. And adding new
grouping constructs for each new feature is not technically
feasible. All of the above may be addressed by generic groups,
which we think is a clean extension to the original architecture of
Manila.
Implements: blueprint manila-share-groups
Change-Id: I8e29baed62355fc31caeec9c7a66eaebfcbdf184
b4250866ea