[CI] XPackRestIT test {p0=ml/start_data_frame_analytics/Test start classification analysis when the dependent variable cardinality is too low} failing

[elasticsearchmachine]

Build Scans:

• elasticsearch-periodic #7433 / openjdk24_entitlements_true_checkpart3_java-matrix
• elasticsearch-pull-request #66310 / part-3
• elasticsearch-pull-request #65993 / part-3

Reproduction Line:

./gradlew ":x-pack:plugin:yamlRestTest" --tests "org.elasticsearch.xpack.test.rest.XPackRestIT.test {p0=ml/start_data_frame_analytics/Test start classification analysis when the dependent variable cardinality is too low}" -Dtests.seed=2AF51D1F410095EF -Dtests.jvm.argline="-Des.entitlements.enabled=true" -Dtests.locale=es-AR -Dtests.timezone=Europe/Rome -Druntime.java=24

Applicable branches:
main

Reproduces locally?:
N/A

Failure History:
See dashboard

Failure Message:

java.lang.AssertionError: Failure at [ml/start_data_frame_analytics:213]: the error message was expected to match the provided regex but didn't
Expected: Field \[keyword_field\] must have at least \[2\] distinct values but there were \[1\]
     but: was "{root_cause=[{type=no_shard_available_action_exception, reason=null, stack_trace=org.elasticsearch.action.NoShardAvailableActionException\n}], type=exception, reason=all shards failed, caused_by={type=search_phase_execution_exception, reason=all shards failed, phase=query, grouped=true, failed_shards=[{shard=0, index=.ml-stats-000001, node=null, reason={type=no_shard_available_action_exception, reason=null, stack_trace=org.elasticsearch.action.NoShardAvailableActionException\n}}], stack_trace=Failed to execute phase [query], all shards failed; shardFailures {[_na_][.ml-stats-000001][0]: org.elasticsearch.action.NoShardAvailableActionException\n}\n\tat [email protected]/org.elasticsearch.action.search.AbstractSearc
[truncated]

Issue Reasons:

• [main] 3 failures in test test {p0=ml/start_data_frame_analytics/Test start classification analysis when the dependent variable cardinality is too low} (0.5% fail rate in 658 executions)
• [main] 2 failures in step part-3 (1.2% fail rate in 169 executions)
• [main] 2 failures in pipeline elasticsearch-pull-request (1.0% fail rate in 192 executions)

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

[elasticsearchmachine]

This has been muted on branch main

Mute Reasons:

• [main] 3 failures in test test {p0=ml/start_data_frame_analytics/Test start classification analysis when the dependent variable cardinality is too low} (0.5% fail rate in 658 executions)
• [main] 2 failures in step part-3 (1.2% fail rate in 169 executions)
• [main] 2 failures in pipeline elasticsearch-pull-request (1.0% fail rate in 192 executions)

Build Scans:

• elasticsearch-periodic #7433 / openjdk24_entitlements_true_checkpart3_java-matrix
• elasticsearch-pull-request #66310 / part-3
• elasticsearch-pull-request #65993 / part-3

[elasticsearchmachine]

Pinging @elastic/es-search-relevance (Team:Search Relevance)

[elasticsearchmachine]

Pinging @elastic/ml-core (Team:ML)

[davidkyle]

no_shard_available_action_exception reading .ml-stats-000001 shortly after it has been created