Installation issues

I recently took over a broken MAAS service (after our Linux admin quit out of the blue) and was reviewing the documentation in an effort to stand up a new production system. I started by reviewing the documentation located here -
How to get MAAS up and running

In reviewing these instructions and following a couple of them…I noticed that PostgreSQL 16 now installs (instead of 14) and I am wondering if these instructions are even needed based upon the file changes. (okay I know Canonical is not best at updating documentation but if you tell a user to update /14 but that folder doesn’t exist because it’s now /16 - well then I am going to question the rest of your commands).

I am falling flat on my face even right off the bat with the first few lines.

sudo -i -u postgres createdb -O "$DBUSER" "$DBNAME"
``'

Is there better examples here? Is the "$DBUSER" meant to be substituted with a user of your making? Similarly with $DBPASS or are those meant to be the same?  
Is there a better resource for documentation in setting up a new MAAS production environment that might guide me through this process?
Lastly - I did create isc-dhcp and bind9 services on this server (those are functional and working properly), however should I just remove these since it appears MAAS has these functions?

Thank you

Hey there,

You are supposed to either populate these bash variables or replace them with strings.

Something like

DBUSER=maas
DBNAME=maasdb
sudo -i -u postgres createdb -O "$DBUSER" "$DBNAME"