JTracker CLI

JTracker is a scientific workflow management system. It provides workflow authoring, sharing and execution with full provenance tracking. JTracker system is designed as client-server architecture for distributed compute environments. All jobs are centrally managed by a JTracker server, JTracker executors (the clients) request jobs/tasks from the server and execute them on compute nodes the executors reside.

Installation

JTracker client needs to be installed on a workflow task execution host. It may be a VM in a cloud environment, an HPC node, or may be just your laptop, or all of them at the same time.

# JTracker cli requires Python3
# install pip3 if not installed already, for Debian or Ubuntu platform do this:
sudo apt-get update
sudo apt-get install python3-pip

# install jtracker
sudo pip3 install jtracker   # pip3 install --upgrade jtracker  # use this to upgrade jtracker to latest version

# if you see usage information with the follow command, you are ready to go
jt --help

Quick test run with demo JTracker workflow

JTracker is in early phase of development, features and behaviours may change as we advance forward. However this quick test run should give you a clear picture how JTracker is designed and how it may fit in your workflow use cases.

Before proceeding further, please make sure you have installed (or upgraded to) the latest version of JT-CLI tool.

This test run uses a demo JT server running at https://jtracker.io.

Note: please do not upload sensitive data when following along the steps.

Register a user account

Please change your_account_name to your own in the following command.

jt user signup -u your_account_name

Log in as the new user

# logging in has not been fully implemented, no password needed for now
jt user login -u your_account_name

Register a JT workflow under your account

The workflow we use for this demo is available here: https://github.com/jtracker-io/demo-workflows/tree/master/webpage-word-count-2.

The workflow git release tag is 'webpage-word-count-2.0.0.1': https://github.com/jtracker-io/demo-workflows/releases/tag/webpage-word-count-2.0.0.1

jt wf register --git-server https://github.com \
               --git-account jtracker-io \
               --git-repo demo-workflows \
               --git-path webpage-word-count-2 \
               --git-tag webpage-word-count-2.0.0.1 \
               --wf-name webpage-word-count-2 \
               --wf-version 0.0.1 \
               --wf-type JTracker

Create a Job Queue for the workflow you would like to run from

The following command creates a job queue for workflow: webpage-word-count-2 with version: 0.0.1.

jt queue add --wf-name webpage-word-count-2 \
             --wf-version 0.0.1

Upon successful creation, you will get a UUID for the new job queue, record it for the next step. In my test, I got 00e2b2e4-f2dc-420a-bb2d-3df6a7984cc3.

It's possible to create a job queue based off a workflow registered under another user given that the workflow is accessible to you. In this case, you provide workflow fullname, eg, user1.webpage-word-count for webpage-word-count workflow owned by user1.

Enqueue some jobs

Now you are ready to add some jobs to the new queue.

# remember to replace '00e2b2e4-f2dc-420a-bb2d-3df6a7984cc3' with your own queue ID
jt job add -q 00e2b2e4-f2dc-420a-bb2d-3df6a7984cc3 -j '{
  "webpage": "[webpage.html]https://dzone.com/cloud-computing-tutorials-tools-news",
  "words": [ "Cloud", "Docker", "Kubernetes", "OpenStack" ]
}'

You can enqueue a couple of more jobs, simply replace webpage_url and words with your favorite values and repeat the above command. New jobs can be added to the queue at any time.

Launch JT executor

Finally, let's launch a JT executor to run those jobs.

# again, replace '00e2b2e4-f2dc-420a-bb2d-3df6a7984cc3' with your own queue ID
jt -V debug exec run -q 00e2b2e4-f2dc-420a-bb2d-3df6a7984cc3 -t 0  # -t 0 disables auto retry on task failure

This will launch an executor that will pull and run jobs from queue 00e2b2e4-f2dc-420a-bb2d-3df6a7984cc3. Current running jobs/tasks will be displayed in stdout (this can be turned off later).

There are some useful options give you control over how jobs/tasks are to be run. For example, -k and -p allow you control how many parallel tasks and jobs the executor can run respectively. Option -c tells executor to run continuously even after it finises all the jobs in the queue. This is useful when you know there will be more jobs to be queued and you don't want to start the executor again. Try jt exec run --help to get more information.

To increase job processing throughput, you can run many JT executors on multiple compute nodes (in any environment cloud or HPC) at the same time.

It's possible to implement auto-scaling on your own, for example, using Kubernetes to increase or decrease worker nodes on which JT executor runs.

Check job status and output

If the executor is still running, you can perform the following commands in a different terminal. To stop an running executor, simply cancel it with Control-C.

Get job status in queue 09360ea8-748a-4a8d-9b55-16b5b7278069.

jt job ls -q 09360ea8-748a-4a8d-9b55-16b5b7278069

Get detail for a particular job c36f6ed7-7639-4ffc-984e-f83e00936d4d in queue 09360ea8-748a-4a8d-9b55-16b5b7278069.

jt job get -j c36f6ed7-7639-4ffc-984e-f83e00936d4d -q 09360ea8-748a-4a8d-9b55-16b5b7278069

In the response JSON you will be able to find the word count result.