Hi!
This is a question and not an issue!

Is there any way to install debian packages before creating the ISO? Ubuntu cloud-init needs access to the Internet to install packages, so I am looking for a solution to inject packages during image creation.

Downloading debian packages and injecting through extras file could be a solution, but managing package dependecies is not easy!

The another possible solution could be chroot, but in which step of the script I should do?

Br,
Meraj