[vCenter] Can't create snapshot (>2GB) with vSphere 6

Given that this particular bug requires that the disk be completely full to manifest, Nathan and I agree that this can be a High priority bug with a comment in release notes.

This was found at Reliance. And really is an issue for any non-trivial size snapshots.
This does need to be addressed, but the only work around available to Mirantis is to adjust the timeouts.

Greg, please have your team figure out the right timeout setting and then have it release note with the recommendation to change the timeout.

Update after investigate this issue:

1. Increasing the timeouts does not help fix the problem!

2. To reproduce this bug not needed generate a file to fill all disk space (steps to reproduce in bug description updated)

3. To resolve this problem need apply this patch https://review.openstack.org/#/c/281134 (Please note "First look at this related issues" in bug description). I tested the fix https://review.openstack.org/#/c/281134 on Fuel 9.0 mos-iso#495 and vCenter 6 and "Export OVF template task failed by timeout" not reproduced.

Timeouts, I've tried to change - https://kb.vmware.com/kb/2144686

For release notes:

1. Not updating the NFC lease - this is addressed with https://review.openstack.org/#/c/281134
2. HTTP timeout when uploading the snapshotted image to Glance - this happens because the OVF exports is taking long time when the root disk is large and HTTP upload to the vSphere datastore times out. The workaround it to increase the HTTP read timeout in vCenter:

Modify the readTimeoutMs setting to 600000 in vpxd.cfg:

<config>
  <vmacore>
    <http>
      <readTimeoutMs>600000</readTimeoutMs>
    </http>
  </vmacore>
..
</config>
Stop and restart vCenter.

https://review.openstack.org/#/c/281134 (complete refactoring of this part of vmware driver in Nova) is not going to be back ported to stable/mitaka, thus, we should restraint from cherry-picking it do 9.0/mitaka downstream branch, unless absolutely necessary.

IMO, the workaround described by Alexander in #6 and increasing of the NFC timeout value (https://kb.vmware.com/kb/2038497) should be sufficient for 9.x.

Marked as "In progress" because the patch is on review https://review.openstack.org/#/c/281134

fix is merged in newton

A release note has been added to 9.2 known issues: https://review.fuel-infra.org/#/c/29729.