Agreed, the instructions could use an adjustment. It seems odd the data part would no longer work.
Longer downtime every year or so is not so bad…
Nope, no problems except for the ones I created by my errant editing of web_only.yml with existing app.yml config. 
Happy to report this now seems to be working for this two container setup!
The only issue that remains is the site text used for telling you how to rebuild from cli (“app”) but that’s a very small thing.
cc: @pfaffman
yeah. that’s hard-coded. If you can’t remember you’ll need to customize the text. 
5 posts were split to a new topic: Build fails due to ruby version mismatch
That can never work. Sorry I missed that before. I updated the OP. If you need to rebuild data, then you need to
./launcher stop web_only; ./launcher rebuild data && ./launcher rebuild web_only
No. That’s exactly what is expected. You can’t rebuild postgres while another postgres is accessing the files. If a new data container is created you need to destroy and start a new web_only container because docker somehow links to the exact container rather than some reference to the one named data.
Thanks for the OP edits 
and help in Build fails due to ruby version mismatch