No, that's Discourse install instructions quick, hand-wavy way of telling you to install Docker if you don't already have it. If your cloud environment already has Docker installed, you can skip that step.

Are you really trying to say that the instructions for installing Docker should be considered in-scope for a guide to install Discourse on a cloud server?

They've included a short snippet that will get you a Docker, in the way recommended by Docker, for whatever your base system is. Many production systems do not move at the pace of Docker development, so it's not practical to run Docker from your distribution's package archive. Some distros will not have distributed packaged Docker releases at all.

What's wrong with these instructions? If you are really "dealing with this" right now, it is worth noting that something like 20 or more supported platforms have specific Docker installation instructions from the Docker website.

https://docs.docker.com/installation/#installation

From a quick sample of those instructions, only the Ubuntu instruction page uses the wget|sh method, and it's using an SSL connection to Docker's own website to add an apt source with signatures in the supported way. This way should work on any Debian-based or Yum-based distro, and writing the instructions like this must likely save Discourse from getting a lot of "How do I docker" issues and e-mails from their clueless users.

So, would you prefer that part just says "installing Docker is out of scope" or should the Discourse developers go through every distro and cloud system and document the specific instructions for that? To do that would completely defeat the purpose of even using Docker at all.

I concur - to elaborate, I'm not actually the one installing Discourse. I support a 'Kumbaya' group of data scientists who have never heard of docker.

Quick directions like these aren't questioned by users who just want to get things done, and they invite security risks just as the parent & article suggest.