The integration tests for Elasticsearch 1.x seems to still be instable, being that the test is failing more frequently recently. One example is .
The last attempt to fix this was
FLINK-5772, in which the test attempts was increased to 3. This doesn't seem to fix the issue. In the worst scenario, since the root cause is an instability with Elasticsearch 1.x's embedded node, and ES 1.x is a very old version that is usually recommended to be upgraded from, we could also consider removing the IT test for ES 1.x.