Pour la config :

'objectstore' => array(
    'class' => 'OC\\Files\\ObjectStore\\Swift',
    'arguments' => array(
        'username' => 'OS_USERNAME',
        'password' => 'OS_PASSWORD', // mot de passe généré dans l'interface OVH
        'bucket' => 'CONTAINER_NAME',
        'autocreate' => false,
        'region' => 'GRA3',
        'url' => 'https://auth.cloud.ovh.net/v2.0',
        'tenantName' => 'OS_TENANT_NAME',
        'serviceName' => 'swift',
    ),
),