How to use yum in Dockerfile correctly

Example of how to install the mkpasswd package using yum in your Dockerfile:

RUN yum -y install mkpasswd && yum -y clean all  && rm -rf /var/cache

There are two basic aspects to remember here:

1. Use yum -y in order to avoid interactive Y/N questions during the automated build
2. Use yum -y clean all && rm -rf /var/cache to clean up after the call to yum -y install

Complete Dockerfile example:

FROM fedora:34
RUN yum -y install mkpasswd && yum -y clean all  && rm -rf /var/cache