I am making a custom ISO w/ autoinstall to automatically install Ubuntu Server onto our machines. We of course need to install some apt packages as part of the customization. The problem is, this installation needs to be done entirely offline, so I can't just add them to the apt package list and have subiquity magic take care of everything.
I am using this method to pack the user-install/autoinstall file into the iso and that is working well.
How can I download apt packages ahead of time, include them on the iso, and have subiquity automatically find and install them?
I found a solution for this here