VMWare : Disabling linked clone does not cache images on the datastore

[Davanum Srinivas (DIMS)]

Comment from @dims on code review - https://review.openstack.org/#/c/37819/

"Shawn, i was going through the code again for this change and realized that when *not* using linked clone we don't the vmware_base dir at all which means we do a fresh transfer of image from glance to hyper every time. Would it be better to still have the vmdk in vmware_base and do a CopyDatastoreFile_Task or CopyVirtualDisk_Task to copy it over into the new directory from vmware_base for each new guest? In other words, we always cache vmdk(s) in vmware_base to skip the network transfer (and hence take the network transfer hit just one for the first time an image is needed in a hyper)"

Response from Shawn:
I was dealing with a test related issue. That I finally resolved by re-introducing some "bad" code, comments are in line with the code. Can you see clear to view that change as out of scope of this patch? That feels like a separate issue from introducing new controls. I would prefer to open a separate bug for this since the feature to turn *off* linked-clone strategy was already present (as a global setting).

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/42024

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/47503

[Shawn Hartsock (hartsock)]

I've bumped the priority of this bug because this will cause exceptionally bad performance for people who are not using linked clones. I've marked this Medium/High because, while the performance is extremely bad without this fix, it is not going to cause failures.

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/47503
Committed: http://github.com/openstack/nova/commit/c53b0f66802ed82fea8c637f0138c0a01e159efa
Submitter: Jenkins
Branch: master

commit c53b0f66802ed82fea8c637f0138c0a01e159efa
Author: Tracy Jones <email address hidden>
Date: Thu Sep 19 16:34:34 2013 -0700

    VMWare: Disabling linked clone doesn't cache images

    This fixes an issue when use_linked_clone is false and the image is
    already in the cache. The problem was that the image would be
    copied from glance into the instance directory even if it was already
    in the cache. This change checks if the file is in the cache, only
    copies from glance if it is not, and copies the image from the cache
    into the instance directory if use_linked_clone is false.

    Fixes: bug #1207064
    Change-Id: Idfa59eb0eb26cce52ff59f97e433deeab6510215

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: stable/grizzly
Review: https://review.openstack.org/50563

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/50563
Committed: http://github.com/openstack/nova/commit/2f94155c34209422ce9c0c3d643e48aa6b367054
Submitter: Jenkins
Branch: stable/grizzly

commit 2f94155c34209422ce9c0c3d643e48aa6b367054
Author: Tracy Jones <email address hidden>
Date: Thu Sep 19 16:34:34 2013 -0700

    VMWare: Disabling linked clone doesn't cache images

    This fixes an issue when use_linked_clone is false and the image is
    already in the cache. The problem was that the image would be
    copied from glance into the instance directory even if it was already
    in the cache. This change checks if the file is in the cache, only
    copies from glance if it is not, and copies the image from the cache
    into the instance directory if use_linked_clone is false.

    Fixes: bug #1207064
    (cherry picked from commit c53b0f66802ed82fea8c637f0138c0a01e159efa)

    Conflicts:

     nova/tests/virt/vmwareapi/test_vmwareapi.py
     nova/virt/vmwareapi/vmops.py

    Change-Id: I635e00448fc014b3841ed43b590d451305e8ff2f