Hi Hugo,

As you are doing an installation on Ubuntu I would recommend doing the installation from the deb package instead of from the source code.

To install from a deb package you can run:

$ sudo dpkg -i package_file.deb

If you want to download the package you can use a system with the same architecture (you can check this with 'dpkg --print-architecture') that has internet access and follow the following steps:

$ echo "deb https://debian.cassandra.apache.org 41x main" | sudo tee -a /etc/apt/sources.list.d/cassandra.sources.list

$ curl https://downloads.apache.org/cassandra/KEYS | sudo apt-key add -

$ sudo apt-get update

$ sudo apt-get download cassanda

If you have dependencies that are not installed you can download all of the dependencies at once:

$ apt-get download $(apt-rdepends <package>|grep -v "^ ")

It is possible you encounter packages that don't have an exact name (e.g. 'E: Can't select candidate version from package debconf-2.0 as it has no candidate'). In those cases, filter out those exact names (be sure to use ^<NAME>$ so that other related names, that do exist are not skipped). For example:

$ apt-get download $(apt-rdepends cassandra|grep -v "^ " | grep -v "^debconf-2.0$" | grep -v "^java11-runtime$" | grep -v "^java8-runtime$" | grep -v "^java8-runtime-headless$")

Copy all these packages to the offline machine and then run (until you no longer have errors):

$ sudo dpkg -i *.deb

Alternatives for offline installations can be through apt-offline which allows you to install packages on an offline machine that can reach an online machine.