Found a solution through the #doctrine IRC channel. The connection must be transmitted separately, because the DocumentManager does not apply the configuration passed to it to the connection that it creates. This will be fixed in a future version. This is how you do it -
// setup the mongodb connection $connection = new \Doctrine\MongoDB\Connection(null, array(), $mongoConfig); // create the document manager for the connection above $dm = \Doctrine\ODM\MongoDB\DocumentManager::create($connection, $mongoConfig);
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