Building images from a Dockerfile

As we described earlier in this chapter, the Dockerfile can be an easy option to create and share the build steps for creating a container image, and for this reason, it is really easy to find a lot of source Dockerfiles on the net.

The first step of this activity is to build a simple Dockerfile to work with. Let's create a Dockerfile for creating a containerized web server:

# mkdir webserver
# cd webserver/
[webserver]# vi Dockerfile 
[webserver]# cat Dockerfile
# Start from latest fedora container base image
FROM fedora:latest
MAINTAINER podman-book  # this should be an email
# Update the container base image
RUN echo "Updating all fedora packages"; dnf -y update; dnf -y clean all
# Install the httpd package
RUN echo "Installing httpd"; dnf -y install httpd
# Expose the http port 80
EXPOSE 80
# Set the default command to run once the container will be started
CMD ["/usr/sbin/httpd", "-DFOREGROUND...