XPN 3.0.0

Expand Ad-Hoc Parallel File System

Homepage: https://xpn-arcos.github.io/xpn-arcos.github.io/
Source: https://github.com/xpn-arcos/xpn
Licence: GNU GENERAL PUBLIC LICENSE Version 3
Authors: Felix Garcia Carballeira, Luis Miguel Sanchez Garcia, Borja Bergua Guerra, Alejandro Calderon Mateos, Diego Camarmas Alonso, Dario Muñoz Muñoz

1. To deploy Ad-Hoc XPN...

The Expand Ad-Hoc Parallel File System (a.k.a. Ad-Hoc XPN) can be installed on a cluster/supercomputer with:

A local storage per-node (HDD, SSD or RAM Drive) accessible through a directory, /tmp for example (this will be the NODE_DIR in this document).
A shared directory among compute nodes used, $HOME for example (this will be the WORK_DIR in this document).

There are only two software pre-requisites that Ad-Hoc XPN needs:

The typical C development tools: gcc, make, and autotools

An MPI implementation compiled with MPI-IO and threads support:

Tested: MPICH 4.1.1 (or compatible) and Intel MPI 2017 (or compatible).
Experimental: OpenMPI 5.0.3 (support is experimental).

If you do not have a compiled MPI implementation with MPI-IO and thread support,
still you can compile MPICH or OpenMPI (experimental) from source code:

Help to compile MPICH from source code... (click to expand)

In order to install the MPICH implementation of MPI (for example, MPICH 4.1.1) from source code and with Infiniband (Omni-Path) support we recommend:

wget https://www.mpich.org/static/downloads/4.1.1/mpich-4.1.1.tar.gz
tar zxf mpich-4.1.1.tar.gz

cd mpich-4.1.1
./configure --prefix=<path where MPICH is going to be installed> \
            --enable-threads=multiple \
            --enable-romio \
            --with-device=ch4:ofi:psm2 \
            --with-libfabric=<path where your libfabric is installed>

make
make install

export LD_LIBRARY_PATH=<path where MPICH is going to be installed>/lib:$LD_LIBRARY_PATH

Help to compile OpenMPI from source code... (click to expand)

For example, in order to install the OpenMPI 5.0.3 implementation of MPI from source code, including Infiniband (Omni-Path) support, we recommend the following steps:

wget https://download.open-mpi.org/release/open-mpi/v5.0/openmpi-5.0.3.tar.gz
tar zxf openmpi-5.0.3.tar.gz

cd openmpi-5.0.3
./configure --prefix=<path where Open MPI is going to be installed> \
            --enable-threads=multiple \
            --enable-romio \
            --with-libfabric=<path where your libfabric is installed>

make
make install

export LD_LIBRARY_PATH=<path where Open MPI is going to be installed>/lib:$LD_LIBRARY_PATH

Once all prerequisites are met, the general steps to deploy XPN are:

%% {init: {"flowchart": {"defaultRenderer": "elk"}} }%%
flowchart TD
  A([Start]) --> B("Do you have 'Spack'?")
  B -- Yes --> ide11
  B -- No --> Y1("Do you have 'modules'?")

  %% (1) with spack
  subgraph ide1 [1 With spack]
  subgraph ide11 [1.1 Add repo]
     direction TB
     X1["git clone https://github.com/xpn-arcos/xpn.git 
        spack repo add xpn/scripts/spack"]
  end
  subgraph ide12 [1.2 Install software]
     direction TB
     X2["spack <b>info</b> xpn
        spack <b>install</b> xpn"]
  end
  subgraph ide13 [1.3 Load software]
     direction TB
     X3["spack <b>load</b> xpn"]
  end
  classDef lt text-align:left,fill:lightgreen,color:black; 
  class X1,X2,X3 lt;
  ide11 --> ide12
  ide12 --> ide13
  end
  ide13 --> I([End])

  Y1-- Yes --> ide21a
  Y1-- No ---> ide21b
  subgraph ide2 [2 With autotools]
  subgraph ide21a [2.1 Load prerequisites]
     direction TB
     Y1A["module avail <br> module load gcc<br> module load 'impi/2017.4'"]
  end
  subgraph ide21b [2.1 Install prerequisites]
     direction TB
     Y1B["sudo apt install -y build-essential libtool<br>sudo apt install -y autoconf automake git<br> sudo apt install -y libmpich-dev mpich"]
  end
  subgraph ide22 [2.2 Download source code]
     direction TB
     Y2B["mkdir $HOME/src 
          cd    $HOME/src 
          git clone https://github.com/xpn-arcos/xpn.git"]
  end
  subgraph ide23 ["2.3 build source code"]
     direction LR
     Y3B["export XPN_MPICC='full path to the mpicc compiler to be used' 
          cd $HOME/src 
          ./xpn/build-me -m $XPN_MPICC -i $HOME/bin"]
  end
  ide21a --> ide22
  ide21b --> ide22
  ide22 --> ide23

  classDef lt2 text-align:left,fill:lightblue,color:black;
  class Y1A,Y1B lt2;
  classDef lt3 text-align:left;
  class Y2B,Y3B lt3;
  end

  Y3B --> I([End])

2. Executing Ad-Hoc XPN...

First, you need to get familiar with 2 special files and 1 special environment variables for XPN client:

%%{ init : { "theme" : "default", "themeVariables" : { "background" : "#000" }}}%%
mindmap
root(("Ad-Hoc XPN"))
  {{Environment<br> Variables}}
      ["`**XPN_CONF=**'full path to the xpn.conf file' <br> \* It is the XPN configuration file to be used (mandatory)`"]
  {{Files}}
      ["`**hostfile**</br>   \* for MPI, it is a text file with the list of host names (one per line) where XPN servers and XPN client is going to be executed`"]
      ["`**xpn.conf**</br>   \* for Ad-Hoc XPN, it is a text file with the configuration for the partition where files are stored at the XPN servers`"]

For Expand developers...

You need to get familiar with 3 special files and 4 special environment variables for XPN client:

%%{ init : { "theme" : "default", "themeVariables" : { "background" : "#000" }}}%%
mindmap
root((Ad-Hoc XPN))
  {{Files}}
      [hostfile]
      [xpn.cfg]
      [stop_file]
  {{Environment Variables}}
      [XPN_CONF]
      [XPN_THREAD]
      [XPN_LOCALITY]
      [XPN_SCK_PORT]

The 3 special files are:

<hostfile> for MPI, it is a text file with the list of host names (one per line) where XPN servers and XPN client is going to be executed.
<xpn.cfg> for XPN, it is the XPN configuration file with the configuration for the partition where files are stored at the XPN servers.
<stop_file> for XPN is a text file with the list of the servers to be stopped (one host name per line).

And the 4 special environment variables for XPN clients are:

XPN_CONF with the full path to the XPN configuration file to be used (mandatory).
XPN_THREAD with value 0 for without threads, value 1 for thread-on-demand and value 2 for pool-of-threads (optional, default: 0).
XPN_LOCALITY with value 0 for without locality and value 1 for with locality (optional, default: 0).
XPN_SCK_PORT with the port to use in internal comunications (opcional, default: 3456).

2.1 Executing Ad-Hoc Expand using MPICH

An example of SLURM job might be:

#!/bin/bash

#SBATCH --job-name=test
#SBATCH --output=$HOME/results_%j.out
#SBATCH --nodes=8
#SBATCH --ntasks=8
#SBATCH --cpus-per-task=8
#SBATCH --time=00:05:00

export WORK_DIR=<shared directory among hostfile computers, $HOME for example>
export NODE_DIR=<local directory to be used on each node, /tmp for example>

scontrol show hostnames ${SLURM_JOB_NODELIST} > $WORK_DIR/hostfile

# Step 1: to launch the Expand MPI servers
<INSTALL_PATH>/xpn/bin/xpn -v \
                           -w $WORK_DIR -x $NODE_DIR \
                           -n <number of XPN processes> \
                           -l $WORK_DIR/hostfile start
sleep 2

  # Step 2: to launch the XPN client (app. that will use Expand)
  mpiexec -np <number of client processes> \
          -hostfile $WORK_DIR/hostfile \
          -genv XPN_CONF    $WORK_DIR/xpn.conf \
          -genv LD_PRELOAD  <INSTALL_PATH>/xpn/lib/xpn_bypass.so:$LD_PRELOAD \
          <full path to the app.>

# Step 3: to stop the MPI servers
<INSTALL_PATH>/xpn/bin/xpn -v -d $WORK_DIR/hostfile stop
sleep 2

The typical executions has 3 main steps:

First, launch the Expand MPI servers:

export WORK_DIR=<shared directory among hostfile computers, $HOME for example>
export NODE_DIR=<local directory to be used on each node, /tmp for example>

<INSTALL_PATH>/xpn/bin/xpn -v \
                           -n <number of processes> \
                           -l $WORK_DIR/hostfile \
                           -w $WORK_DIR \
                           -x $NODE_DIR \
                           start

Then, launch the program that will use Expand (XPN client).

2.1. Example for the app1 MPI application:

  export WORK_DIR=<shared directory among hostfile computers, $HOME for example>

   mpiexec -np               <number of processes> \
           -hostfile         $WORK_DIR/hostfile \
           -genv XPN_CONF    $WORK_DIR/xpn.conf \
           -genv LD_PRELOAD  <INSTALL_PATH>/xpn/lib/xpn_bypass.so:$LD_PRELOAD \
           <full path to app1>/app1

2.2. Example for the app2 program (a NON-MPI application):

  export WORK_DIR=<shared directory among hostfile computers, $HOME for example>
  export XPN_CONF=$WORK_DIR/xpn.conf

  LD_PRELOAD=<INSTALL_PATH>/xpn/lib/xpn_bypass.so <full path to app2>/app2

2.3. Example for the app3.py Python program:

  export WORK_DIR=<shared directory among hostfile computers, $HOME for example>
  export XPN_CONF=$WORK_DIR/xpn.conf

  LD_PRELOAD=<INSTALL_PATH>/xpn/lib/xpn_bypass.so python3 <full path to app3>/app3.py

At the end of your working session, you need to stop the MPI servers:

export WORK_DIR=<shared directory among hostfile computers, $HOME for example>

<INSTALL_PATH>/xpn/bin/xpn  -v -d $WORK_DIR/hostfile stop

2.2 Executing Ad-Hoc Expand using OpenMPI (experimental alpha)

An example of SLURM job might be:

#!/bin/bash

#SBATCH --job-name=test
#SBATCH --output=$HOME/results_%j.out
#SBATCH --nodes=8
#SBATCH --exclusive
#SBATCH --time=00:05:00

export WORK_DIR=<shared directory among hostfile computers, $HOME for example>
export NODE_DIR=<local directory to be used on each node, /tmp for example>

scontrol show hostnames ${SLURM_JOB_NODELIST} > $WORK_DIR/hostfile

# Step 1
prte --hostfile $WORK_DIR/hostfile --report-uri $WORK_DIR/prte --no-ready-msg &
sleep 2
NAMESPACE=$(cat $WORK_DIR/prte | head -n 1 | cut -d "@" -f 1)

# Step 2: to launch the Expand MPI servers
mpiexec -n ${SLURM_NNODES} \
        --hostfile $WORK_DIR/hostfile \
        --dvm ns:$NAMESPACE \
        --map-by ppr:1:node:OVERSUBSCRIBE \
        <INSTALL_PATH>/bin/xpn_server &
sleep 2

  # Step 3: to launch the XPN client (app. that will use Expand)
  mpiexec  -n <number of processes: 2> \
           -hostfile $WORK_DIR/hostfile \
          --dvm ns:$NAMESPACE \
           -mca routed direct \
          --map-by node:OVERSUBSCRIBE \
           -x XPN_CONF=$WORK_DIR/xpn.conf \
           -x LD_PRELOAD=<INSTALL_PATH>/xpn/lib/xpn_bypass.so:$LD_PRELOAD \
          <full path to the app.>

# Step 4: to stop the MPI servers
<INSTALL_PATH>/xpn/bin/xpn -v -d $WORK_DIR/hostfile stop
sleep 2

The typical executions has 4 main steps:

First, launch the OpenMPI prte server:

 export WORK_DIR=<shared directory among hostfile computers, $HOME for example>
 export NODE_DIR=<local directory to be used on each node, /tmp for example>

 prte --hostfile $WORK_DIR/hostfile --report-uri $WORK_DIR/prte --no-ready-msg &
 NAMESPACE=$(cat $WORK_DIR/prte | head -n 1 | cut -d "@" -f 1)

Second, launch the Expand servers:

mpiexec -n <number of processes>  -hostfile $WORK_DIR/hostfile \
        --dvm ns:$NAMESPACE \
        --map-by ppr:1:node:OVERSUBSCRIBE \
        <INSTALL_PATH>/bin/xpn_server &

Then, launch the program that will use Expand (XPN client).

3.1. Example for the app1 MPI application:

export WORK_DIR=<shared directory among hostfile computers, $HOME for example>

 mpiexec -n <number of processes>  -hostfile $WORK_DIR/hostfile \
         -mca routed direct \
         --map-by node:OVERSUBSCRIBE \
         --dvm ns:$NAMESPACE \
         -genv XPN_CONF    $WORK_DIR/xpn.conf \
         -genv LD_PRELOAD  <INSTALL_PATH>/xpn/lib/xpn_bypass.so:$LD_PRELOAD \
         <full path to app1>/app1

3.2. Example for the app2 program (a NON-MPI application):

export WORK_DIR=<shared directory among hostfile computers, $HOME for example>
export XPN_CONF=$WORK_DIR/xpn.conf

LD_PRELOAD=<INSTALL_PATH>/xpn/lib/xpn_bypass.so <full path to app2>/app2

3.3. Example for the app3.py Python program:

export WORK_DIR=<shared directory among hostfile computers, $HOME for example>
export XPN_CONF=$WORK_DIR/xpn.conf

LD_PRELOAD=<INSTALL_PATH>/xpn/lib/xpn_bypass.so python3 <full path to app3>/app3.py

At the end of your working session, you need to stop the Expand servers:

export WORK_DIR=<shared directory among hostfile computers, $HOME for example>

./xpn -v -d $WORK_DIR/hostfile stop

For Expand developers...

Summary:

sequenceDiagram
    job            ->> mk_conf.sh: generate the XPN configuration file
    mk_conf.sh     ->> xpn.conf: generate the xpn.conf file
    job            ->> xpn_server: (1) launch the Expand MPI server
    xpn.conf      -->> xpn_server: read the XPN configuration file
    job            ->> XPN client: (2) launch the program that will use Expand
    xpn.conf      -->> XPN client: read the XPN configuration file
    XPN client      -> xpn_server: write and read data
    XPN client    -->> job: execution ends
    job            ->> xpn_server: (3) stop the MPI server

acaldero / xpn

XPN 3.0.0

1. To deploy Ad-Hoc XPN...

2. Executing Ad-Hoc XPN...

2.1 Executing Ad-Hoc Expand using MPICH

2.2 Executing Ad-Hoc Expand using OpenMPI (experimental alpha)

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