NXDOC-2686: Document Amazon DocumentDB support

Author: NourNuxeo

src/nxdoc/nuxeo-server/administration/database-configuration.md

@@ -163,6 +163,7 @@ This takes two steps:
     *   [MySQL]({{page page='mysql'}})
     *   [MariaDB]({{page page='mariadb'}})
     *   [MongoDB]({{page page='mongodb'}})
+    *   [DocumentDB]({{page page='documentdb'}})
 2.  [Connect Nuxeo to the database]({{page page='connecting-nuxeo-to-the-database'}}).
 
  

src/nxdoc/nuxeo-server/administration/database-configuration/documentdb.md

@@ -0,0 +1,50 @@
+---
+title: Amazon DocumentDB
+labels:
+    - database
+    - documentdb
+tree_item_index: 700
+
+---
+`DocumentDB` is compatible with `MongoDB`, therefore, it can be used by `Nuxeo` like a `MongoDB` backend,
+but there are limitations.
+
+{{#> callout type='warning'}}
+Only DocumentDB "instance cluster" has been successfully tested with Nuxeo.
+The DocumentDB  [elastic cluster](https://docs.aws.amazon.com/documentdb/latest/developerguide/docdb-using-elastic-clusters.html) behaves differently from MongoDB regarding index initialization. At the moment it cannot be used by Nuxeo.
+{{/callout}}
+
+## Limitations
+
+- fulltext search at repository level using `DocumentDB` is not supported due to `DocumentDB` limitations. You need to rely on `Elasticsearch` or `OpenSearch`. This requires to disable repository fulltext search. See the [configuration]({{page space='nxdoc' page='documentdb#configuration'}}) section.
+- retryable writes are not supported. You need to disable this. See the [configuration]({{page space='nxdoc' page='documentdb#configuration'}}) section.
+- the `DocumentDB` instance type chosen affects the number of open cursor at any given time.
+
+Note there are also other differences that should not affect Nuxeo. Please refer to `DocumentDB`:
+- [Differences With MongoDB](https://docs.aws.amazon.com/documentdb/latest/developerguide/text-search.html#text-index-mongo-diff)
+- [Functional Differences](https://docs.aws.amazon.com/documentdb/latest/developerguide/functional-differences.html#functional-differences.with-mongodb)
+
+## Configuration
+
+To use `DocumentDB` you need the following options:
+
+```properties
+nuxeo.templates=<MY_TEMPLATES>,mongodb
+nuxeo.vcs.fulltext.search.disabled=true
+nuxeo.mongodb.server=<MONGO_URL>?retryWrites=false
+```
+
+For all other configuration information, please refer to the [MongoDB configuration page]({{page page='mongodb'}}).
+
+* * *
+
+<div class="row" data-equalizer data-equalize-on="medium"><div class="column medium-6">{{#> panel heading='Related topics'}}
+
+- [Connecting Nuxeo to the Database]({{page page='connecting-nuxeo-to-the-database'}})
+- [How to Estimate Volume Usage]({{page page='how-to-estimate-volume-usage'}})
+
+{{/panel}}</div><div class="column medium-6">
+
+&nbsp;
+
+</div></div>