feat(doc): example debian packaging inside docker container

doc/building.rst

@@ -111,6 +111,79 @@ The procedure below works on OpenBSD 5.8 with gcc version 4.8.4, cmake version 3
    cmake ..
    make
 
+Building Debian Packages inside Docker Container with CMake on Ubuntu or Debian
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+Here is an example howto build the library as Debian package inside a Docker container
+
+- Download and install
+
+  - Docker Engine: https://docs.docker.com/install/linux/docker-ce/debian/
+  - docker-deb-builder: https://github.com/tsaarni/docker-deb-builder.git
+  - open62541: https://github.com/open62541/open62541.git
+
+Install Docker as described at https://docs.docker.com/install/linux/docker-ce/debian/ .
+
+Get the docker-deb-builder utility from github and make Docker images for the needed
+Debian and/or Ubuntu relases
+
+.. code-block:: bash
+
+   # make and goto local development path (e.g. ~/development)
+   mkdir ~/development
+   cd ~/development
+
+   # clone docker-deb-builder utility from github and change into builder directory
+   git clone https://github.com/tsaarni/docker-deb-builder.git
+   cd docker-deb-builder
+
+   # make Docker builder images (e.g. Ubuntu 18.04 and 17.04)
+   docker build -t docker-deb-builder:18.04 -f Dockerfile-ubuntu-18.04 .
+   docker build -t docker-deb-builder:17.04 -f Dockerfile-ubuntu-17.04 .
+
+Make a local copy of the open62541 git repo and checkout a pack branch
+
+.. code-block:: bash
+
+   # make a local copy of the open62541 git repo (e.g. in the home directory) 
+   # and checkout a pack branch (e.g. pack/1.0)
+   cd ~
+   git clone https://github.com/open62541/open62541.git
+   cd ~/open62541
+   git checkout pack/1.0
+
+Now it's all set to build Debian/Ubuntu open62541 packages
+
+.. code-block:: bash
+
+   # goto local developmet path
+   cd ~/development
+   
+   # make a local output directory for the builder where the packages can be placed after build
+   mkdir output
+   
+   # build Debian/Ubuntu packages inside Docker container (e.g. Ubuntu-18.04)
+   ./build -i docker-deb-builder:18.04 -o output ~/open62541
+
+After a successfull build the Debian/Ubuntu packages can be found at :file:`~/development/docker-deb-builder/output`
+
+CMake Build Options and Debian Packaging
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+If the open62541 library will be build as a Debian package using a pack branch (e.g. pack/master or pack/1.0)
+then altering or adding CMake build options should be done inside the :file:`debian/rules` file respectively in
+the :file:`debian/rules-template` file if working with a development branch (e.g. master or 1.0).
+
+The section in :file:`debian/rules` where the CMake build options are defined is 
+
+.. code-block:: bash
+
+   ...
+   override_dh_auto_configure:
+       dh_auto_configure -- -DBUILD_SHARED_LIBS=ON -DCMAKE_BUILD_TYPE=RelWithDebInfo -DUA_NAMESPACE_ZERO=FULL -DUA_ENABLE_AMALGAMATION=OFF -DUA_PACK_DEBIAN=ON
+   ...
+
+This CMake build options will be passed as command line variables to CMake during Debian packaging.
 
 .. _build_options: