Quick start

The CLI tool is called e4s-cl. It behaves as a supplementary launcher over regular MPI commands, but can also manage profiles containing information about a MPI library’s dependencies.

Setting up a profile

The preferred way to start using e4s-cl is to create a profile for the target library. The intended method to achieve this is by using the init or profile detect commands.

$ e4s-cl init
$ e4s-cl profile list
 == Profile Configurations (/storage/users/fdeny/.local/e4s_cl/user.json) =======
 +----------+---------------+---------+-------+
 | Selected |     Name      | Backend | Image |
 +==========+===============+=========+=======+
 |    *     | MVAPICH@2.3.4 |     N/A |   N/A |
 +----------+---------------+---------+-------+
$ e4s-cl profile show
 Profile name: MVAPICH@2.3.4
 Container image: Not found
 Container tech: Not found
 Pre-execution script: None
 Wi4MPI installation: None

 Bound libraries:
  - libgfortran.so.5 (/lib64/libgfortran.so.5)
  - libibumad.so.3 (/lib64/libibumad.so.3)
  [...]
  - libmlx5-rdmav34.so (/usr/lib64/libibverbs/libmlx5-rdmav34.so)

 Bound files:
  - /etc/libibverbs.d/mlx5.driver
  [...]
  - /usr/share/hwdata/pci.ids

The resulting profile can be inspected and modified using the profile sub-commands. A typical profile setup will involve specifying the backend to use as well as the image in which to run the binary:

$ e4s-cl profile edit --backend singularity --image ./image.sif
$ e4s-cl profile list
 == Profile Configurations (/storage/users/fdeny/.local/e4s_cl/user.json) =======
 ----------+---------------+-------------+-------------+
 | Selected |     Name      |   Backend   |    Image    |
 +==========+===============+=============+=============+
 |    *     | MVAPICH@2.3.4 | singularity | ./image.sif |
 +----------+---------------+-------------+-------------+

Running e4s-cl barebones

e4s-cl is also able to run binaries directly on the host’s environment. To do so, select the barebones backend. This usually will only work when the binary was also compiled in the host’s environment.

$ e4s-cl profile edit --backend barebones
$ e4s-cl profile list
 == Profile Configurations (/storage/users/fdeny/.local/e4s_cl/user.json) =======
 ----------+---------------+-------------+-------------+
 | Selected |     Name      |   Backend   |    Image    |
 +==========+===============+=============+=============+
 |    *     | MVAPICH@2.3.4 |  barebones  |     None    |
 +----------+---------------+-------------+-------------+

Running a process

Once a profile has been created, it can be used to launch an MPI command! The profile select command marks a profile as the default. Using the launch command, the program passed as an argument will be launched using the desired library.

$ e4s-cl launch mpirun -np 4 -hosts node1,node2 /path/to/executable

When the executable was compiled with an ABI-incompatible MPI from the host’s MPI, use the --from flag to signal to e4s-cl to enable translation. For a list of MPI families and values to use, refer to the MPI implementations section.