[17.12] Fix IP overlap with empty EndpointSpec

[thaJeztah]

cherry-pick of #2505 for 17.12

git checkout -b 17.12-backport-fixendpointspec upstream/bump_v17.12
git cherry-pick -s -S -x bd4e923c241ff1f9a493eab02125edbf6ec0b901

(no conflicts)

Passing and empty EndpointSpec in the service spec
was correctly triggering the VIP allocation but
the leader election was erroneusly handling the IPAM
state restore trying to release the VIP.
The fix focuses on proper handling of the restart case.

Signed-off-by: Flavio Crisciani flavio.crisciani@docker.com
(cherry picked from commit bd4e923)
Signed-off-by: Sebastiaan van Stijn github@gone.nl

[thaJeztah]

ping @fcrisciani PTAL

[fcrisciani]

Code looks good but the CI failed on a test that is flacky, @nishanttotla @anshulpundir can you guys restart it?

[nishanttotla]

LGTM.

Restarted CI.

[andrewhsu]

@nishanttotla perhaps need another kick of the ci?

[nishanttotla]

CI seems to keep failing @andrewhsu :(

[andrewhsu]

i see it too:

time="2018-02-16T23:41:07Z" level=error msg="task allocation failure" error="failed to retrieve network testID3 while allocating task testTaskID3" 
time="2018-02-16T23:41:08Z" level=error msg="Failed allocation for network testID5" error="failed while allocating driver state for network testID5: could not obtain vxlan id for pool 10.0.4.0/24: requested bit is already allocated" 
time="2018-02-16T23:41:08Z" level=error msg="task allocation failure" error="network testID5 attached to task testTaskID6 not allocated yet" 
time="2018-02-16T23:41:08Z" level=error msg="Failed allocation for service testServiceID4" error="requested bit is already allocated" 
time="2018-02-16T23:41:08Z" level=error msg="task allocation failure" error="service testServiceID4 to which this task testTaskID7 belongs has pending allocations" 
--- FAIL: TestNodeAllocator (0.04s)
	allocator_test.go:1190: timed out before watchNode found expected node state

[codecov]

Codecov Report

Merging #2513 into bump_v17.12 will decrease coverage by 5.28%.
The diff coverage is 50%.

@@               Coverage Diff               @@
##           bump_v17.12    #2513      +/-   ##
===============================================
- Coverage        66.92%   61.63%   -5.29%     
===============================================
  Files               76      129      +53     
  Lines            11158    21233   +10075     
===============================================
+ Hits              7467    13087    +5620     
- Misses            2929     6741    +3812     
- Partials           762     1405     +643