Basic OS Housekeeping Questions - Ubuntu/CentOS - dual entries in /etc/hosts

I am really enjoying these projects. Thank you!

I finished an exercise successfully, but there were some questions I still have.

01: I was looking for the /etc/fstab files for my exercise to make a configuration persistent. I didn’t see the file on any of the app servers, so I wondered what OS I was using.

uname -a showed ubuntu.
cat /etc/os-release showed centos7.

Turns out, the exercise didn’t require an /etc/fstab entry, but I thought this was interesting.

02: The other thing I noticed is that /etc/hosts for nautilus systems seem to have two line entries in /etc/hosts for the primary ip address. This has caused me issues in the past, and now I typically just comment out the line for the non-fqdn line. (Which takes a little time) In my work experience, I typically configure my systems using the ip/fqdn/shortname. Just wondered if I am missing something with the two line entries. I see it on all projects I think. stapp01 (Is this necessary?) stapp01 ( Config I normally would expect) stapp01 (Not talking about this line)

Thanks again!

@myeek thanks you for sharing this. We do not keep fstab intentionally and none of the question would ask to make any changes in there.

About entries in hosts, that are also intentional.