WebRuntimeMonitorITCase.testNoCopyFromJar failing intermittently

Test failed randomly in Travis,
https://s3.amazonaws.com/archive.travis-ci.org/jobs/122624299/log.txt

Tests run: 5, Failures: 1, Errors: 0, Skipped: 0, Time elapsed: 13.127 sec <<< FAILURE! - in org.apache.flink.runtime.webmonitor.WebRuntimeMonitorITCase
testNoCopyFromJar(org.apache.flink.runtime.webmonitor.WebRuntimeMonitorITCase) Time elapsed: 0.124 sec <<< FAILURE!
java.lang.AssertionError: expected:<200 OK> but was:<503 Service Unavailable>
at org.junit.Assert.fail(Assert.java:88)
at org.junit.Assert.failNotEquals(Assert.java:743)
at org.junit.Assert.assertEquals(Assert.java:118)
at org.junit.Assert.assertEquals(Assert.java:144)
at org.apache.flink.runtime.webmonitor.WebRuntimeMonitorITCase.testNoCopyFromJar(WebRuntimeMonitorITCase.java:456)

Results :

Failed tests:
WebRuntimeMonitorITCase.testNoCopyFromJar:456 expected:<200 OK> but was:<503 Service Unavailable>