mkdir -p dockerfile/C7httpd; cd dockerfile/C7httpd
vi Dockerfile

FROM centos:7
MAINTAINER "Steve Netting" steve@netting.org.uk
ENV container docker
RUN yum -y --setopt=tsflags=nodocs update && \
yum -y --setopt=tsflags=nodocs install httpd && \
yum clean all

EXPOSE 80

ADD run-httpd.sh /run-httpd.sh
RUN chmod -v +x /run-httpd.sh

CMD ["/run-httpd.sh"]

vi run-httpd.sh

#!/bin/bash

# Make sure we're not confused by old, incompletely-shutdown httpd
# context after restarting the container. httpd won't start correctly
# if it thinks it is already running.
rm -rf /run/httpd/* /tmp/httpd*

exec /usr/sbin/apachectl -DFOREGROUND

docker build .
docker images
docker run -d -p:8082:80 steve/httpd:latest
docker ps
curl http://localhost:8082

... If you can read this page it means that this site is working properly ...

To start interactive shell from inside running container:
docker exec -i -t romantic_noyce /bin/bash