Dockerfile

# Please read carefully

# 1)
# pull centos 7 the latest version
# centos is public on docker hub
# check  https://hub.docker.com/_/centos
FROM    centos:7


# 2)
# Run the image in a container and execute yum update
# and yum install httpd on the container.
# You can have many RUN commands
RUN     yum update -y && yum install httpd -y


# 3)
# Informs Docker that the container listens on the specified network ports
# Though does not actually publish the port.
# It functions as a type of documentation between the person who builds the image
# and the person who runs the container, about which ports are intended to be published
EXPOSE  80


# 4)
# After apache httpd installation, start apache server on the container.
# There can only be one CMD instruction in a Dockerfile.
# If you list more than one CMD then only the last CMD will take effect.
CMD     ["/usr/sbin/httpd","-D","FOREGROUND"]


# 5)
# Then copy files (e.g. index.html) from the host to
# /var/www/html/ on the container.
COPY    index.html /var/www/html/
COPY    img/leo.jpg /var/www/html/img/
COPY    img/rongxin.png /var/www/html/img/
COPY    img/sergey.png /var/www/html/img/

# 6)
# If everything went fine then docker
# will package the container as a new image
# and then stop and remove the container, so
# docker images
# should contain the new image

#Please read : https://docs.docker.com/engine/reference/builder/