Data To Compute

January 14-16 2020


Montpellier, France

Jason Coposky


Executive Director, iRODS Consortium

Data To Compute

Integrating iRODS with a compute environment

In order of increasing complexity and integration...


iRODS as a compute orchestrator

  • Launch a job via irule, or as part of a PEP
  • Implement a Landing Zone for product capture


iRODS as part of a compute job script

  • Stage the source data via replication for the application
  • Capture the products and ingest them into iRODS


iRODS as part of the compute application

  • Compute application directly leverages the iRODS API to open, read, and write data

The Data to Compute Use Case

Focus on the right side of the picture

iRODS is out of the data path for computation

Goal - Develop generic interface concept for compute

  • Develop a metadata-driven interface to drive path for input data and compute results. Utilize it to
    • push data to the proper storage resource
    • get a name for the host on which to launch compute job(s)


  • Separate configuration from implementation
    • Keep deployment specifics in configuration files
    • Keep rule-base, scripts, and modules free of hard-wired values

Goal - Develop a thumbnailing service for iRODS

Interface is through iRODS and SLURM (compute job scheduler):

  • Replicate the data to the compute resource
  • Send a job to the compute scheduler to generate thumbnails
  • Register the thumbnails into the catalog
  • Replicate the thumbnails back to long term storage
  • Trim replicas on compute resource

Components of the System

System Component

Job Scheduler

Job Launching Script

Tools to Execute

Job Endpoint




Image Magick convert

iRODS Rule Base

(user extension of the iRODS API)

and SLURM prolog / epilog

Getting Started

Installing Image Magick

sudo apt-get update
sudo apt-get -y install imagemagick

Installing the PRC (Python iRODS-Client) module

Installing the python rule engine plugin

sudo apt-get -y install irods-rule-engine-plugin-python
sudo apt-get -y install python-pip
sudo pip install python-irodsclient

Getting Started

Get the irods_training repository

git clone
sudo apt-get -y install irods-externals-cmake3.5.2-0 irods-dev
export PATH=/opt/irods-externals/cmake3.5.2-0/bin/:$PATH
mkdir build_data_to_compute
cd build_data_to_compute
cmake ../irods_training/advanced/hpc_data_to_compute/
make package
sudo dpkg -i ./irods-hpc-data-to-compute-example_4.2.6~xenial_amd64.deb

Build and Install MUNGE and SLURM (job scheduler)

Build and Install the Data to Compute package

cd ~/irods_training/advanced/hpc_data_to_compute/

Package Contents

$ dpkg -c ./irods-hpc-data-to-compute-example_4.2.6~xenial_amd64.deb

drwxrwxr-x root/root         0 2019-06-20 21:21 ./etc/
drwxrwxr-x root/root         0 2019-06-20 21:21 ./etc/irods/
-r--r--r-- root/root      1213 2019-06-20 21:12 ./etc/irods/
-r--r--r-- root/root      1144 2019-06-20 12:38 ./etc/irods/
drwxrwxr-x root/root         0 2019-06-20 21:21 ./var/
drwxrwxr-x root/root         0 2019-06-20 21:21 ./var/lib/
drwxrwxr-x root/root         0 2019-06-20 21:21 ./var/lib/irods/
drwxrwxr-x root/root         0 2019-06-20 21:21 ./var/lib/irods/compute/
-r--r--r-- root/root         0 2019-06-16 18:38 ./var/lib/irods/compute/
-rw------- root/root        59 2019-06-20 12:38 ./var/lib/irods/compute/admin_as_rodsuser.json
-r--r--r-- root/root     11755 2019-06-20 21:12 ./var/lib/irods/compute/
-r--r--r-- root/root      2005 2019-06-16 18:38 ./var/lib/irods/compute/irods_compute_functions
-r--r--r-- root/root       565 2019-06-20 21:12 ./var/lib/irods/compute/job_params.json
-r--r--r-- root/root      2150 2019-06-20 21:12 ./var/lib/irods/compute/
-r--r--r-- root/root      1301 2019-06-20 12:38 ./var/lib/irods/
drwxrwxr-x root/root         0 2019-06-20 21:21 ./var/lib/irods/msiExecCmd_bin/
-r-xr-xr-x root/root       383 2019-06-20 12:34 ./var/lib/irods/msiExecCmd_bin/convert.SLURM
-r-xr-xr-x root/root       343 2019-06-16 18:38 ./var/lib/irods/msiExecCmd_bin/
-r--r--r-- root/root       788 2019-06-20 12:38 ./var/lib/irods/rescName_from_kvpair.r
-r--r--r-- root/root      1494 2019-06-20 21:12 ./var/lib/irods/spawn_remote_slurm_jobs.r

Configure the rule engine

As the irods user, add an additional rule base to

 /etc/irods/server_config.json :
"rule_engines": [


        "re_rulebase_set": [






(Remember that order matters!)

Add in a small python rule-base:

As the irods user, create an /etc/irods/ with

the following content:

import sys
from compute.util import pyParseRoleSpec

Python Rule Engine Configuration (re-ordering)

Edit rule engine order in /etc/irods/server_config.json :

  • insert the python plugin configuration stanza after the iRODS Rule Language plugin
  • if it already exists elsewhere in the config, move (cut/paste) it from that location, but it must occur only once.
  • for this exercise, native rule code must supersede python!
"rule_engines": [
         "instance_name": "irods_rule_engine_plugin-irods_rule_language-instance",


         "instance_name" : "irods_rule_engine_plugin-python-instance",
         "plugin_name" : "irods_rule_engine_plugin-python",
         "plugin_specific_configuration" : {}

Configure the LTS and Image Processing Resources

As the irods user:


Make two unix file system resources

iadmin mkresc lts_resc unixfilesystem `hostname`:/tmp/irods/lts_resc
iadmin mkresc img_resc unixfilesystem `hostname`:/tmp/irods/img_resc

Annotate them with appropriate metadata given their roles

  - defined in the configuration as part of the contract

cp ~/irods_training/stickers.jpg /tmp
sudo mkdir -p /tmp/irods/thumbnails
sudo chown -R irods:irods /tmp/irods

As the ubuntu user:


Stage data and destination directory for thumbnail creation

The configuration interface

Define interfaces for any necessary conventions

  • Metadata attributes and values

  • Metadata values for implemented roles

  • Interface to job scheduler for launching compute


Single Point of Truth - allows for the use of the same 'end-points' for various metadata standards and naming conventions


Users may utilize metadata conventions to provide inputs to a given compute job

The configuration interface

For the thumbnail service we will need to

  • Get the metadata attribute string that holds the role

  • Get the tag for an Image Compute resource

  • Get the tag for a Long Term Storage resource

  • Get the logical collection name for thumbnails

  • Get the physical path for a thumbnail

  • Get the name of a thumbnail

  • Get a list of desired thumbnail sizes

The configuration interface

iRODS rule file provides interface for job submission

  *thumbnail_sizes = "128x128,256x256,512x512,1024x1024"
  *host = ""
  # or even: # *key = "COMPUTE_RESOURCE_ROLE=IMAGE_PROCESSING"; *val=""
  *resc_name = ""
  get_host_and_resource_name_by_role(*host, *resc_name, *key, *val)
  writeLine ("stdout", "host=[*host] resc=[*resc_name]")
  writeLine ("stdout", "thumbnails to generate : [ *thumbnail_sizes ]")
  *input_file_name = "stickers"
  *input_file_ext = ".jpg"
  *input_file =  "*input_file_name" ++ "*input_file_ext"
  if ("*host" == "" ) {
    writeLine ("stdout", "Host for job launch was not found.")
  } else {
    foreach (*x in select DATA_PATH where COLL_NAME = '/tempZone/home/rods' and
                   DATA_NAME = '*input_file' and RESC_NAME = '*resc_name')
     *src_phy_path = *x.DATA_PATH
    remote(*host, "") {
      writeLine("serverLog", "-----> remoteExec on host [*host]:")
      foreach (*size in split (*thumbnail_sizes, ",")) {
        *dst_phy_path = "/tmp/irods/thumbnails/" ++ "*input_file_name" ++ "_thumbnail_" ++ "*size" ++ "*input_file_ext"
        writeLine("serverLog"," - thumbsize [ *size ]; convert ( *src_phy_path , *dst_phy_path )")
        *cmd_opts="/var/lib/irods/msiExecCmd_bin/convert.SLURM -thumbnail *size *src_phy_path *dst_phy_path"
      } #foreach
    } #remote
  } #if-else
} # end rule

INPUT  null
OUTPUT ruleExecOut


The configuration interface

Abstraction of job submission via shell script


# $1 - executable
# $2 - thumbnail option
# $3 - sizing string
# $4 - source physical path
# $5 - destination physical path

SBATCH_OPTIONS="-o /tmp/slurm-%j.out"

SCRIPT="$1" # assume full path to executable

/usr/local/bin/sbatch $SBATCH_OPTIONS "$SCRIPT" \
    ${2+"$2"} \
    ${3+"$3"} \
    ${4+"$4"} \
    ${5+"$5"} \
    >/dev/null 2>&1


Thumbnail Service - testing

irods@icat:~$ COMPUTE_RESC=$(iquest %s " select RESC_NAME where META_RESC_ATTR_NAME = \
irods@icat:~$ iput -R ${COMPUTE_RESC} /tmp/stickers.jpg
irods@icat:~$ ils -l
  rods              0 img_resc      2157087 2019-06-20.22:07 & stickers.jpg

irods@icat:~$ irule -F spawn_remote_slurm_jobs.r
irods@icat:~$ squeue
                 2     debug convert.    irods  R       0:05      1 icat
                 3     debug convert.    irods  R       0:05      1 icat
                 4     debug convert.    irods  R       0:05      1 icat
                 5     debug convert.    irods  R       0:05      1 icat
irods@icat:~$ squeue 
irods@icat:~$ iquest "%s : %s/%s" "select RESC_NAME,COLL_NAME,DATA_NAME where DATA_NAME like '%thumbnail%'"
lts_resc : /tempZone/home/rods/stickers_thumbnails/stickers_thumbnail_1024x1024.jpg
lts_resc : /tempZone/home/rods/stickers_thumbnails/stickers_thumbnail_128x128.jpg
lts_resc : /tempZone/home/rods/stickers_thumbnails/stickers_thumbnail_256x256.jpg
lts_resc : /tempZone/home/rods/stickers_thumbnails/stickers_thumbnail_512x512.jpg


(Wait for the SLURM job queue to be empty: )

As the irods user, position the input data and start the thumbnail jobs:

Extending iRODS with the Rule Engine

  • All rules should be created and tested in user space before being installed as a rule base

  • Rules may be refactored into a microservice plugin

  • Rules may be refactored into a C++ rule engine plugin

  • Rules may be refactored into an API plugin

CINES 2020 - Data to Compute

By jason coposky

CINES 2020 - Data to Compute

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