diff --git a/documentation/operator-guide/configuration.rst b/documentation/operator-guide/configuration.rst
index 327832e46be3b71202293e4df20d59354518231b..e9ac61e2b5b2cd48ed15fbc6984e087df105eab6 100644
--- a/documentation/operator-guide/configuration.rst
+++ b/documentation/operator-guide/configuration.rst
@@ -240,18 +240,252 @@ such a configuration file is defined and the used in a service:
The following configuration files are used throughout the VS:
-* ``<stack-name>_init-db.sh``: This shell script file's purpose is to set up
- the EOxServer instance used by both the renderer and registrar.
-* ``<stack-name>_index-dev.html``/``<stack-name>_index-ops.html``: The
- clients main HTML page, containing various client settings. The ``dev`` one
- is used for development only, whereas the ``ops`` one is used for operational
- deployment.
-* ``<stack-name>_mapcache-dev.xml``/``<stack-name>_mapcache-ops.xml``: The
- configuration file for MapCache, the software powering the cache service.
- Similarly to the client configuration files, the ``dev`` and ``ops`` files
- used for development and operational usage respectively. Further
- documentation can be found at `the official site
- <https://mapserver.org/mapcache/config.html>`_.
+``<stack-name>_init-db.sh``
+~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+This shell script file's purpose is to set up the EOxServer instance used by
+both the renderer and registrar.
+
+``<stack-name>_index-dev.html``/``<stack-name>_index-ops.html``
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+The clients main HTML page, containing various client settings. The ``dev`` one
+is used for development only, whereas the ``ops`` one is used for operational
+deployment.
+
+``<stack-name>_mapcache-dev.xml``/``<stack-name>_mapcache-ops.xml``
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+The configuration file for MapCache, the software powering the cache service.
+Similarly to the client configuration files, the ``dev`` and ``ops`` files
+used for development and operational usage respectively. Further
+documentation can be found at `the official site
+<https://mapserver.org/mapcache/config.html>`_.
+
+``<stack-name>_preprocessor-config.yaml``
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+The configuration for the proprocessing service to use to process to be
+ingested files.
+
+The files are using YAML as a format and are structured in the following
+fashion:
+
+source/target
+
+ Here, the source file storage and the target file storage are configured.
+ This can either be a local directory or an OpenStack Swift object storage.
+
+workdir
+
+ The workdir can be configured, to determine where the intermediate files are
+ placed. This can be convenient for debugging and development.
+
+keep_temp
+
+ This boolean decides if the temporary directory for the preprocessing will be
+ cleaned up after being finished. Also, convenient for development.
+
+metadata_glob
+
+ This file glob is used to determine the main metadata file to extract the
+ product type from. This file will be searched in the downloaded package.
+
+type_extractor
+
+ This setting configures how the product type is extracted from the previously
+ extracted metadata. In the ``xpath`` setting one or more XPath expressions
+ can supplied to fetch the product type. Each XPath will be tried until one is
+ found that produces a result. These results can then be mapped using the
+ ``map`` dictionary.
+
+level_extractor
+
+ This section works very similar to the ``type_extractor`` but only for the
+ product level. The product level is currently not used.
+
+preprocessing
+
+ This is the actual preprocessing configuration setting. It is split in
+ defaults and product type specific settings. The defaults are applied
+ where there is no setting supplied for that specific type. The product type
+ is the one extracted earlier.
+
+ defaults
+
+ This section allows to configure any one of the available steps. Each step
+ configuration can be overridden in a specific product type configuration.
+
+ The available steps are as follows:
+
+ custom_preprocessor
+
+ A custom python function to be called.
+
+ path
+
+ The Python module path to the function to call.
+
+ args
+
+ A list of arguments to pass to the function.
+
+ kwargs
+
+ A dictionary of keyword arguments to pass to the function.
+
+ subdatasets
+
+ What subdatasets to extract and how to name them.
+
+ data_file_glob
+
+ A file glob pattern to select files to extract from.
+
+ subdataset_types
+
+ Mapping of subdataset identifier to output filename postfix for
+ subdatasets to be extracted for each data file.
+
+ georeference
+
+ How the extracted files shall be georeferenced.
+
+ type
+
+ The type of georeferencing to apply. One of ``gcp``, ``rpc``,
+ ``corner``, ``world``.
+
+ options
+
+ Additional options for the georeferencing. Depends on the type of
+ georeferencing.
+
+ order
+
+ The polynomial order to use for GCP related georeferencing.
+
+ projection
+
+ The projection to use for ungeoreferenced images.
+
+ rpc_file_template
+
+ The file glob template to use to find the RPC file. Template
+ parameters are {filename}, {fileroot}, and {extension}.
+
+ warp_options
+
+ Warp options. See
+ https://gdal.org/python/osgeo.gdal-module.html#WarpOptions for
+ details
+
+ corner_names
+
+ The metadata field name including the corner names. Tuple of four:
+ bottom-left, bottom-right, top-left and top-right
+
+ orbit_direction_name
+
+ The metadata field name containing the orbit direction
+
+ force_north_up
+
+ TODO
+
+ tps
+
+ Whether to use TPS transformation instead of GCP polynomials.
+
+ calc
+
+ Calculate derived data using formulas.
+
+ formulas
+
+ A list of formulas to use to calculate derived data. Each has the
+ following fields
+
+ inputs
+
+ A map of characters in the range of A-Z to respective inputs. Each
+ has the following properties
+
+ glob
+
+ The input file glob
+
+ band
+
+ The input file band index (1-based)
+
+ data_type
+
+ The GDAL data type name for the output
+
+ formula
+
+ The formula to apply. See
+ https://gdal.org/programs/gdal_calc.html#cmdoption-calc for details.
+
+ output_postfix
+
+ The postfix to apply for the filename of the created file.
+
+ nodata_value
+
+ The nodata value to be used.
+
+ stack_bands
+
+ Concatenate bands and arrange them in a single file.
+
+ group_by
+
+ A regex to group the input datasets, if consisting of multiple file.
+ The first regex group is used for the grouping.
+
+ sort_by
+
+ A regex to select a portion of the filename to be used for sorting. The
+ first regex group is used.
+
+ order
+
+ The order of the extracted item used in 'sort_by'. When the value
+ extracted by ``sort_by`` is missing, then that file will be dropped.
+
+ output
+
+ Final adjustments to generate an output file. Add overviews, reproject to
+ a common projection, etc.
+
+ options
+
+ Options to be passed to `gdal.Warp`. See
+ https://gdal.org/python/osgeo.gdal-module.html#WarpOptions for details.
+
+ custom_preprocessor
+
+ A custom python function to be called.
+
+ path
+
+ The Python module path to the function to call.
+
+ args
+
+ A list of arguments to pass to the function.
+
+ kwargs
+
+ A dictionary of keyword arguments to pass to the function.
+
+ types
+
+ This mapping of product type identifier to step configuration allows to
+ define specific step settings, even overriding the values from the
+ defaults.
The next section :ref:`management` describes how an operator interacts with a
deployed VS stack.