In the 17.1 FFU guide, there is a section that describes overcloud adoption and upgrade preparation for multi-cell environments. This section is more of an example and points to the "regular" for Performing the overcloud adoption and preparation more information on the steps. This is causes a disjointed customer experience that might be hard to follow for a user with a multi-cell environment.

The non-multicell overcloud adoption procedure is nearly the same as the multi-cell adoption procedure. I propose copying that procedure and creating a multi-cell version with multi-cell specific steps to replace the current multi-cell overcloud adoption section.

I started a draft here:  Performing the overcloud adoption and preparation for multi-cell environments