I am using a fresh installation of Magento 2.2.1.
After creating a configurable product with the attribute "width" as the configuration, I also updated the weight of each of the simple products that have been created automatically. The weight is visible in the configurable product configuration table as well as in each of the simple products individually as expected. I activated the setting to show the weight attribute in the store front and it is visible in the "Attributes" tab of the product. However, when changing the width of the product, the weight (actually non of the attributes, e.g. volume) is not updated as one would expect. Only the weight of the parent / configurable product is shown and never updated. This also is the case for the SKU, which is certainly different for each of the configurations.
My question is: What is the correct way to connect multiple attributes to the configurable products, i.e. how to update the weight (or any) attribute in the store front according to the width option.
As a related side-question: Why does the weight not show the unit that is visible in the back-end? When setting the weight, there is a gray-ish unit "kgs" so I naturally assume the store front should know about this unit as well.