+.. note:: the image build process is based on `diskimage-builder
+ <https://docs.openstack.org/diskimage-builder/latest/index.html>`_
+ that will be installed in a Python virtual environment by nfvbenchvm
+ build script build-image.sh.
+
+.. note:: build-image.sh uses the `gsutil <https://pypi.org/project/gsutil/>`_
+ tool to interact with Google cloud storage (to check if the images
+ exist and to upload the images). This is normally only needed in the
+ context of OPNFV build infrastructure, and build-image.sh can be used
+ without that tool in development environments.
+