His point is not "I don't know how to deploy a Rails app", it's "there is no standard way for a server program to tell the OS how what services to configure, or to query the OS for what services are available. Instead of fixing this, we wrap a pre-configured-OS-image and run it inside our OS. This is daft". As well as "the instructions are incorrect and incomplete, and that's normal".
e.g.
Set aside the oddball tool breakage and consider that if you follow the instructions to the letter, this web forum requires: cloning (not installing!) the software’s source code and modifying it in-place. Copy-pasting hundreds of lines of configuration into nginx, as root, and hoping it doesn’t change when you upgrade. Installing non-default Postgres extensions, as root. Running someone else’s arbitrary database commands as a superuser.
and
You’d think that a web app could just have some metadata saying “I need Postgres and, optionally, Redis”, but this doesn’t exist. And the other side, where the system can enumerate the services it has available for a user, similarly doesn’t exist. So there’s no chance of discovery. If you’re missing a service the app needs but failed to document, or you set it up wrong, you’ll just find out on the first request.
and
"What we should have by now" section.
and
And I’m really not picking on Ruby, or Rails, or this particular app. I hate deploying my own web software, because there are so many parts all over the system that only barely know about each other, but if any of them fail then the whole shebang stops working.
