custom-image-dockerfile

##Base image
FROM centos 
##Author name
LABEL author="AUTHOR_NAME" 
##Description for this custom image
LABEL description="This is a custom AMI"  
##Packages to install in the container
RUN yum update -y && yum install httpd -y && yum install git -y && yum install java -y 
## Port number to expose for the container
EXPOSE 80 
## Environment variable in the dockerfile
ENV dir /var/www/html 
## Copy index file from host machine to container machine.
COPY ./index.html $dir 
## Download a file from internet and copy to container machine.
ADD http://mirrors.jenkins.io/war-stable/latest/jenkins.war $dir 
## start the apache server
CMD ["/usr/sbin/httpd","-D","FOREGROUND"] 
#ENTRYPOINT
## Create a folder
RUN mkdir /myvol 
## add contents to the greeting file
RUN echo "This is a persistent voume" > /myvol/greeting 
## Create a persistent volume that is available even after the container is destroyed
VOLUME /myvol
## Set the working directory
WORKDIR $dir 
## Create a dynamic variabe whose value will be passed outside the dockerfile using "--build-arg"
ARG file 
## Passing the value from ARG
RUN touch $file 
## Passing the value from ARG
RUN mkdir $file.html 
## Providing the onbuild instructions that will get executed when using this image as a base image.
ONBUILD RUN touch index.html 
## Providing the onbuild instructions that will get executed when using this image as a base image.
ONBUILD RUN mkdir index_folder 
## Providing the onbuild instructions that will get executed when using this image as a base image.
ONBUILD RUN yum install mysql -y 
## Create a healthcheck for the application running inside the container.
HEALTHCHECK CMD curl -f http://YOUR_MACHINE_IP_ADDRESS:8080/index.html || exit 1