The `DEBIAN_FRONTEND` environment variable is used to control the interface by which debconf questions are presented to the user (see [`man 7 debconf`][1]). In `DEBIAN_FRONTEND=noninteractive apt-get update && apt-get install -y`, the `DEBIAN_FRONTEND` environment variable is only set for the `apt-get update` command which does not ask debconf questions, and will not affect the `apt-get install` command where these questions are actually asked. It should be the other way around.
[1]: https://manpages.debian.org/debconf.7.html
Signed-off-by: Murukesh Mohanan <murukesh.mohanan@gmail.com>
(cherry picked from commit 7227c0145d)
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>