unable to initialize frontend: Dialog

These errors don’t stop the image from being built but inform you that the installation process tried to open a dialog box, but was unable to. Generally, these errors are safe to ignore.

Some people circumvent these errors by changing the DEBIAN_FRONTEND environment variable inside the Dockerfile using:

ENV DEBIAN_FRONTEND=noninteractive

This prevents the installer from opening dialog boxes during installation which stops the errors.

While this may sound like a good idea, it may have side effects. The DEBIAN_FRONTEND environment variable will be inherited by all images and containers built from your image, effectively changing their behavior. People using those images will run into problems when installing software interactively, because installers will not show any dialog boxes.

Because of this, and because setting DEBIAN_FRONTEND to noninteractive is mainly a ‘cosmetic’ change, we discourage changing it.