migration docs audit

qdrant-landing/content/documentation/migrate-to-qdrant/from-opensearch.md

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+---
+title: From OpenSearch
+weight: 45
+---
+
+# Migrate from OpenSearch to Qdrant
+
+## What You Need from OpenSearch
+
+- **OpenSearch URL** — the HTTP endpoint
+- **Index name** — the index containing your vectors
+- **Credentials** — username/password or API key
+
+## Concept Mapping
+
+| OpenSearch | Qdrant | Notes |
+| :--- | :--- | :--- |
+| Index | Collection | One-to-one mapping |
+| Document | Point | Each document becomes a point |
+| `knn_vector` field | Vector | Mapped automatically |
+| Document fields | Payload | Non-vector fields become payload |
+| `cosinesimil` | `Cosine` | Direct mapping |
+| `l2` | `Euclid` | Direct mapping |
+| `innerproduct` | `Dot` | Direct mapping |
+
+## Run the Migration
+
+```bash
+docker run --net=host --rm -it registry.cloud.qdrant.io/library/qdrant-migration opensearch \
+    --opensearch.url 'https://your-opensearch-host:9200' \
+    --opensearch.index 'your-index' \
+    --opensearch.username 'admin' \
+    --opensearch.password 'your-password' \
+    --qdrant.url 'https://your-instance.cloud.qdrant.io:6334' \
+    --qdrant.api-key 'your-qdrant-api-key' \
+    --qdrant.collection 'your-collection'
+```
+
+### Using API Key Authentication
+
+```bash
+docker run --net=host --rm -it registry.cloud.qdrant.io/library/qdrant-migration opensearch \
+    --opensearch.url 'https://your-opensearch-host:9200' \
+    --opensearch.index 'your-index' \
+    --opensearch.api-key 'your-opensearch-api-key' \
+    --qdrant.url 'https://your-instance.cloud.qdrant.io:6334' \
+    --qdrant.api-key 'your-qdrant-api-key' \
+    --qdrant.collection 'your-collection'
+```
+
+### All OpenSearch-Specific Flags
+
+| Flag | Required | Description |
+| :--- | :--- | :--- |
+| `--opensearch.url` | Yes | OpenSearch HTTP endpoint |
+| `--opensearch.index` | Yes | Index to migrate |
+| `--opensearch.username` | No | Username for basic auth |
+| `--opensearch.password` | No | Password for basic auth |
+| `--opensearch.api-key` | No | API key for authentication |
+| `--opensearch.insecure-skip-verify` | No | Skip TLS certificate verification |
+
+### Qdrant-Side Options
+
+| Flag | Default | Description |
+| :--- | :--- | :--- |
+| `--qdrant.id-field` | `__id__` | Payload field name for original OpenSearch document IDs |
+
+## Gotchas
+
+- **OpenSearch vs. Elasticsearch:** OpenSearch is a fork of Elasticsearch, so many of the same considerations apply. However, the CLI subcommand is `opensearch`, not `elasticsearch`.
+- **Score normalization:** OpenSearch `_score` values are not directly comparable to Qdrant scores. Use rank-based metrics when [verifying your migration](/documentation/migration-verification/).
+- **Nested documents:** OpenSearch nested documents need to be flattened or restructured for Qdrant's payload model.
+
+## Next Steps
+
+After migration, verify your data arrived correctly with the [Migration Verification Guide](/documentation/migration-verification/).