Update container_info.md to include both bind and hybrid example

container_info.md

@@ -84,3 +84,67 @@ srun --exclusive --ntasks=4 --cpus-per-task=1 --nodes=1  --mem 3000M singularity
 echo 'finished'
 ```
 
+***
+For the same example, using a **hybrid** approach, here is a definition file.  The important change is that the environment sets the OMPI variables to use the openmpi version within the container:
+```
+Bootstrap: docker
+From: ubuntu:20.04
+
+%files
+    ./mpi-hello-world/mpi_hello_world.c /opt
+    ./mpi-hello-world/makefile /opt
+
+%environment
+    export OMPI_DIR=/opt/ompi
+    export SINGULARITY_OMPI_DIR=$OMPI_DIR
+    export SINGULARITYENV_APPEND_PATH=$OMPI_DIR/bin
+    export SINGULAIRTYENV_APPEND_LD_LIBRARY_PATH=$OMPI_DIR/lib
+
+%post
+    echo "Installing base packages..."
+    apt-get update -y  && . /etc/environment
+    apt-get install wget gcc bash g++ make libsysfs2 libsysfs-dev libevent-dev libpmix-dev -y
+    
+    echo "Installing Open MPI"
+    export OMPI_DIR=/opt/ompi
+    export OMPI_VERSION=4.1.3
+    export OMPI_URL="https://download.open-mpi.org/release/open-mpi/v4.1/openmpi-$OMPI_VERSION.tar.bz2"
+    mkdir -p /tmp/ompi
+    mkdir -p /opt
+    ##  Download
+    cd /tmp/ompi && wget -O openmpi-$OMPI_VERSION.tar.bz2 $OMPI_URL && tar -xjf openmpi-$OMPI_VERSION.tar.bz2
+    # Compile and install
+    cd /tmp/ompi/openmpi-$OMPI_VERSION && ./configure --enable-orterun-prefix-by-default --with-pmix=/usr/lib/x86_64-linux-gnu/pmix/ --prefix=$OMPI_DIR && make install
+    # Set env variables so we can compile our application
+    export PATH=$OMPI_DIR/bin:$PATH
+    export LD_LIBRARY_PATH=$OMPI_DIR/lib:$LD_LIBRARY_PATH
+    export MANPATH=$OMPI_DIR/share/man:$MANPATH
+
+    echo "Compiling the MPI application..."
+    cd /opt
+    make
+```
+In addition to using a hybrid approach, the mpi_hello_world application is compiled as part of the "post" section of the .def file using the command "make".  This required modifying the "files" section to include the source (.c) and the makefile.  
+
+The correspond slurm script:
+```
+#!/bin/bash
+#SBATCH --ntasks=4  ## number of MPI tasks
+#SBATCH --cpus-per-task=1  ## number of cores per task
+#SBATCH --time=00:01:00
+#SBATCH --mem 3000M 
+#SBATCH --nodes=1
+#SBTACH --ntasks-per-node=4
+
+module load openmpi/4.1.3
+module load singularityce
+
+
+echo 'start'
+
+srun --exclusive --ntasks=4 --cpus-per-task=1 --nodes=1  --mem 3000M singularity exec ./hellompihybrid  /opt/mpi_hello_world
+
+echo 'finished'
+```
+
+Further testing of the MPI container could include a multi-node slurm script, and an MPI program that utilizes more MPI features (such as sending messages between tasks).