Enforce quota limitations for instance resize.

Fixes LP 1030010.

Close off a back-door allowing users to go over-quota on ram
and/or cores by creating a tiny instance and then resizing
to any size regardless of the remaining usage headroom.

The quota management logic is distributed in the sense that
the reservations are passed with the RPC casts that may fail
silently, so that the rollback or commit is handled by the
actor finalizing the resize/confirmation/reversion.

Up-sizing requires there is sufficient quota headroom upfront
to accommodate the larger size, whereas conversely down-sizing
only results in a usage reduction when the resize is confirmed.

Change-Id: I2b1cbb098c79e37d7ad19221fe23657eb018eae6

0 files changed, 0 insertions, 0 deletions