Propose: VMware ephemeral disk support

This blueprint implements improve-vmware-disk-usage.

Change-Id: I6197a81084e494bc15d40cfe15fd6aed714f0107
Previously-approved: Juno

specs/kilo/approved/vmware-ephemeral-disk-support.rst

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+..
+ This work is licensed under a Creative Commons Attribution 3.0 Unported
+ License.
+
+ http://creativecommons.org/licenses/by/3.0/legalcode
+
+=============================
+VMware Ephemeral Disk Support
+=============================
+
+https://blueprints.launchpad.net/nova/+spec/improve-vmware-disk-usage
+
+The blueprint adds support for support ephemeral disks to the VMware driver.
+
+Problem description
+===================
+
+The VMware driver does not support ephemeral disks.
+
+Use Cases
+----------
+
+Driver parity. All virt driver should implement the same set of basic
+features (including ephemeral disks). So that when a user uses Nova
+they don't have to worry about which virt driver they are using if
+they are using basic features.
+
+Project Priority
+-----------------
+
+None
+
+Proposed change
+===============
+
+The change will add ephemeral disk support to the VMware driver. The commit
+acec2579b796d101f732916bfab557a66cebe512 added in a method create_virtual_disk.
+This method will be used to create the ephemeral disk for the instance.
+
+The method will create an ephemeral disk for the instance on the datastore.
+This will be done according to the size defined in the instance flavor.
+
+Alternatives
+------------
+
+* Do not implement the feature.
+
+Data model impact
+-----------------
+
+None.
+
+REST API impact
+---------------
+
+None.
+
+Security impact
+---------------
+
+None.
+
+Notifications impact
+--------------------
+
+None.
+
+Other end user impact
+---------------------
+
+* Users will be able to use ephemeral disks for the vCenter driver.
+
+Performance Impact
+------------------
+
+A modest increase in network traffic will slow down spawn operations as we
+create the ephemeral disk, size it, and place it for mounting in the vSphere
+virtual machine.
+
+Other deployer impact
+---------------------
+
+None.
+
+Developer impact
+----------------
+
+None.
+
+
+Implementation
+==============
+
+Assignee(s)
+-----------
+
+Primary assignee:
+  garyk
+  heut2008
+
+Work Items
+----------
+
+* refactor and port https://review.openstack.org/#/c/51793/ for Kilo
+
+Dependencies
+============
+
+blueprint vmware-spawn-refactor
+
+Testing
+=======
+
+* Minesweeper tests involving ephemeral disks will be turned on or written
+
+
+Documentation Impact
+====================
+
+After this blueprint the vmware driver will support ephemeral disks. This will
+need some additional documentation and changes to supported feature lists.
+
+References
+==========
+
+None