instruction: Create a Dockerfile for fundamentals
output: ```dockerfile
  from a packageIf you can't use Docker's rpm repository to install Docker Engine, you can
  download the .rpm file for your release and install it manually. You need to
  download a new file each time you want to upgrade Docker Engine.Go to https://download.docker.com/linux/centos/
  and choose your version of CentOS. Then browse to x86_64/stable/Packages/
  and download the .rpm file for the Docker version you want to install.Install Docker Engine, changing the following path to the path where you downloaded
  the Docker package.
  
  $ sudo dnf install /path/to/package.rpm
  Docker is installed but not started. The docker group is created, but no
  users are added to the group.Start Docker Engine.
  
  $ sudo systemctl enable --now docker
  This configures the Docker systemd service to start automatically when you
  boot your system. If you don't want Docker to start automatically, use sudo systemctl start docker instead.Verify that the installation is successful by running the hello-world image:
  
  $ sudo docker run hello-world
  This command downloads a test image and runs it in a container. When the
  container runs, it prints a confirmation message and exits.You have now successfully installed and started Docker Engine.
  TipReceiving errors when trying to run without root?The docker user group exists but contains no users, which is why youâre required
  to use sudo to run Docker commands. Continue to
  Linux postinstall
  to allow non-privileged users to run Docker commands and for other optional configuration steps.Upgrade Docker EngineTo upgrade Docker Engine, download the newer package files and repeat the
  <a class=link href=#install-
  ```