[CI] MixedClusterClientYamlTestSuiteIT test {p0=indices.upgrade/20_deprecated/Basic test for upgrade indices < 7.11.0} failing

[elasticsearchmachine]

Build Scans:

• elasticsearch-periodic #9088 / 7.5.2_bwc
• elasticsearch-periodic #9037 / 7.3.2_bwc

Reproduction Line:

./gradlew ':qa:mixed-cluster:v7.5.2#mixedClusterTest' -Dtests.class="org.elasticsearch.backwards.MixedClusterClientYamlTestSuiteIT" -Dtests.method="test {p0=search.aggregation/240_max_buckets/Max bucket}" -Dtests.seed=5E2351CF018B3C9A -Dtests.bwc=true -Dtests.locale=zh-TW -Dtests.timezone=Australia/Yancowinna -Druntime.java=22

Applicable branches:
7.17

Reproduces locally?:
N/A

Failure History:
See dashboard

Failure Message:

java.lang.RuntimeException: Failure at [search.aggregation/240_max_buckets:100]: Connection refused

Issue Reasons:

• [7.17] 2 failures in test test {p0=indices.upgrade/20_deprecated/Basic test for upgrade indices < 7.11.0} (2.4% fail rate in 85 executions)
• [7.17] 2 failures in pipeline elasticsearch-periodic (25.0% fail rate in 8 executions)

Note:
This issue was created using new test triage automation. Please report issues or feedback to es-delivery.

[elasticsearchmachine]

Pinging @elastic/es-delivery (Team:Delivery)