Add VSAN policy update code to admin api

[andrewjstone]

Add unit test for vsan_policy.update in admin cli

Add docs for vsan policy update in admin cli

Tested via make all and CI, as well as manual tests.

Fixes #329

[msterin]

Nice - and easy to review / read :-)

[andrewjstone]

haha :D

[msterin]

All in all the code looks good.

• A few nits and suggestions (mainly about logging).
• Main concern - the CI actually fails (out of space - see below), but the status does show OK - so
• (1) something is still broken in CI reporting, most likely 'make test-esx' (I thought I've fixed it though) , and it may hide other issues
• (2) you mentioned manual tests - can you also provide what exactly did you test manually, what was the result and why did you decide against piutting it in automatesd testing

CI log says:

Running unit tests in /tmp/vmdk_ops_unittest11080/vmdk_ops_test.py...
....FF
======================================================================
FAIL: testPolicy (__main__.VmdkCreateRemoveTestCase)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/tmp/vmdk_ops_unittest11080/vmdk_ops_test.py", line 125, in testPolicy
    self.assertEqual(err == None, unit[2], err)
AssertionError: {u'Error': 'Failed to create /vmfs/volumes/vsan:5204bc8bc03e1c20-5a4696067b772017/dockvols/vol_UnitTest_Create0.vmdk. Failed to create virtual disk: There is not enough space on the file system for the selected operation (13).\n'}

[andrewjstone]

The automated tests are actually more comprehensive than the manual tests I performed. Manually, I only created and updated a policy file to check the output, and then tried to update wiht the same content to watch it fail. I didn't actually create any volumes to use a policy manually.

The only reason I did the manual tests was to sanity check my vsan/nimbus install and see the output before I ran make all.

[msterin]

I still see

AssertionError: {u'Error': 'Failed to create /vmfs/volumes/vsan:5204bc8bc03e1c20-5a4696067b772017/dockvols/vol_UnitTest_Create.vmdk. Failed to create virtual disk: There is not enough space on the file system for the selected operation (13).\n'}

in the CI log (which still shows as PASSED). Please take a look (the rest looks good, after merge conflicts cleanup)

[pdhamdhere]

nit: All => Some

[andrewjstone]

I meant All. I just moved it inside the next conditional to be more clear.

[pdhamdhere]

Overall LGTM. Some minor suggestions above.

[andrewjstone]

@msterin I have no idea why failing tests wouldn't cause CI to fail. Clearly they are failing correctly due to lack of space and being marked as failures by python test infrastructure. make test-esx also seems to work correctly so I'm at a bit of a loss. Will dig a bit further when CI comes back online and I rebase to latest master, before merge.

[andrewjstone]

This branch was rebased on main and comments were addressed. make all passes against my nimbus setup with VSAN. Since this merge requires VSAN testing, it should probably wait until CI covers that, although I believe it's safe to merge now.

[msterin]

LGTM - but please wait with merge until VSAN in CI is back on-line and CI passes (/cc @kerneltime )

[msterin]

LGTM