[CI] RolloverIT#testRolloverWithDateMath failed at midnight

[dnhatn]

The rollover test with the date pattern happened and failed at midnight.

1> [2018-02-19T11:59:59,017][INFO ][o.e.a.a.i.r.RolloverIT   ] [testRolloverWithDateMath]: before test
...
1> [2018-02-19T12:00:00,546][INFO ][o.e.a.a.i.r.RolloverIT   ] [RolloverIT#testRolloverWithDateMath]: cleaning up after test

The new index name was derived from the next day rather than today.

FAILURE 1.85s J2 | RolloverIT.testRolloverWithDateMath <<< FAILURES!
   > Throwable #1: java.lang.AssertionError: 
   > Expected: "test-2018.02.19-000004"
   >      but: was "test-2018.02.20-000004"
   > 	at __randomizedtesting.SeedInfo.seed([DE29C74DF54CE353:5FEB5F63B28659FB]:0)
   > 	at org.hamcrest.MatcherAssert.assertThat(MatcherAssert.java:20)
   > 	at org.elasticsearch.action.admin.indices.rollover.RolloverIT.testRolloverWithDateMath(RolloverIT.java:232)

CI: https://elasticsearch-ci.elastic.co/job/elastic+elasticsearch+6.x+multijob-unix-compatibility/os=sles/695/console
Log: testRolloverWithDateMath.txt

[alexander-marquardt]

@saudurehman and myself have seen this manifest itself at the client site using version 6.2.2.

When rollover happened, the alias points to a different index than what was created. At midnight, the index was created for the next day, but the alias still pointed to the previous day.

Index created was 2018-03-27-000004 but the alias was pointing to 2018-03-26-000004.

(this appears related to the following closed issue: #24803)

[s1monw]

@alexander-marquardt I am not sure this is related. The rollover API doesn't guarantee you any dates. it will use whatever it creates. The code looks correct this is a test issue.