[Failing Test]: Milvus RAG integration tests fail consistently in beam_PreCommit_Python_ML (py3.13) #38945

What happened?

The Milvus RAG integration tests fail consistently on the beam_PreCommit_Python_ML workflow (observed on Python 3.13, on both ubuntu-latest and self-hosted runners). This does not look like an intermittent flake: the last 4 completed runs on master all failed.

Failing suites:

• apache_beam.ml.rag.enrichment.milvus_search_it_test.TestMilvusSearchEnrichment (e.g. test_hybrid_search, test_empty_input_chunks, test_filtered_search_with_cosine_similarity_and_batching, test_invalid_query_on_non_existent_collection, ...)
• apache_beam.ml.rag.ingestion.milvus_search_it_test.TestMilvusVectorWriterConfig (e.g. test_idempotent_write, test_write_with_batching, ...)

Several of the failures are 10-minute timeouts, which suggests the Milvus testcontainer fails to come up (or is unreachable) rather than an assertion-level regression.

Recent failing runs on master:

• https://github.com/apache/beam/actions/runs/27419037714 (2026-06-12, push)
• https://github.com/apache/beam/actions/runs/27409079139 (2026-06-12, schedule)
• https://github.com/apache/beam/actions/runs/27393791579 (2026-06-12, schedule)
• https://github.com/apache/beam/actions/runs/27378617857 (2026-06-11, schedule)

Also reproduced on unrelated PR runs, e.g. https://github.com/apache/beam/actions/runs/27417091271 (PR #38493, which touches no ML code).

Related: #31285 tracks general flakiness of this job; filing this separately since the Milvus suites currently fail on every run.

Issue Priority

Priority: 2 (default / most failing tests should be filed as P2)

Issue Components

• Component: Python SDK
• Component: Java SDK