Maxwell : Creating a Docker image

As an example let us consider how centos_mpi image is created.

1. Create a Dockerfile
   
   

   Dockerfile

   # The base image. If not present, will be loaded from Dockerhub automatically
   FROM centos:7
   
   #
   MAINTAINER Sergey Yakubov <sergey.yakubov@desy.de>
   
   # RUN command executes a bash command. Every command creates a layer in a union
   # filesystem which are then put one on top of other to get a final image.
   # Several commands can be joined with && to avoid too many filesystem layers
   
   # install ssh, set pam parameter
   RUN yum install -y openssh-clients openssh-server && ssh-keygen -A && \
       sed -i 's/required\(.*pam_loginuid\)/optional\1/' /etc/pam.d/sshd
   
   
   # install infiniband
   RUN yum install -y ibibverbs-utils libibverbs-devel libibverbs-devel-static \
   	libmlx4 libmlx5 ibutils libibcm libibcommon libibmad libibumad rdma \
   	librdmacm-utils librdmacm-devel librdmacm libibumad-devel perftest
   
   # install mpi
   RUN yum install -y openmpi openmpi-devel make
   # needed for current package version to avoid error messages
   RUN echo "mtl = ^ofi" >> /etc/openmpi-x86_64/openmpi-mca-params.conf
   
   # ENV command sets environment variable which can be accessed when container is started
   ENV PATH=/usr/lib64/openmpi/bin:$PATH
   ENV LD_LIBRARY_PATH=/usr/lib64/openmpi/lib:$LD_LIBRARY_PATH
   
   # add path to mpi to start-up scripts
   RUN echo "export PATH=/usr/lib64/openmpi/bin:${PATH}" > /etc/profile.d/scripts-path.sh && \
   	echo "export LD_LIBRARY_PATH=/usr/lib64/openmpi/lib:$LD_LIBRARY_PATH" >> /etc/profile.d/scripts-path.sh &&\
   	chmod 755 /etc/profile.d/scripts-path.sh
   
   

    

    

2.  As soon as this files are ready we can build docker image (called from the directory where the files are).

   $ docker build -t <your Dockerhub name>/centos_mpi .

3. We can now upload the image into Docker Hub

   $ docker push <your Dockerhub name>/centos_mpi