Parallelism for Entire Kedro Pipeline

Question

I am working on a project where we are processing very large images. The pipeline has several nodes, where each produces output necessary for the next node to run. My understanding is that the ParallelRunner is running the nodes in parallel. It is waiting for each process to finish the 1st node before moving onto the 2nd, etc. My problem is is that the inputs take varying amounts of time to complete. So many processes are stuck waiting for others to finish a node, when it is not necessary, as each process in parallel has no dependency on another, only its own previously computed results.

Is there a way to run the entire pipeline in parallel on different cores? I do not want each parallel process to wait for the other processes to finish a node. I have the idea that I could accomplish this by creating multiple copies of my kedro project and modify their data catalogs to process different parts of the dataset and then run these in parallel using the subprocess module, but this seems inefficient.

Answer 1

EDIT:

My understanding is that the ParallelRunner is running the nodes in parallel. It is waiting for each process to finish the 1st node before moving onto the 2nd, etc.

Not sure if I understand this correctly but as soon as a process finishes, it will move on immediately to the next node ready to be executed. It shouldn't wait on anything.

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There is an alternative along the same line of your idea about multiple projects. However, you don't need to create multiple copies of the project to achieve the same result. You can parameterise a run with a certain set of inputs and write a wrapper script (bash, python, etc.) to invoke as many kedro run as you want. For example, if you want to have a dedicated Kedro run, which will then be on its own process, for one file in the data/01_raw directory, you could do:

for input in data/01_raw/*
do
    file=$(basename $input)
    kedro run --params=input:"$file"
done

The trick to make this work is implement a before_pipeline_run hook to dynamically add a catalog entry with the value of the input parameter. I have a demo repository here to demonstrate this technique: https://github.com/limdauto/demo-kedro-parameterised-runs -- let me know if this addresses your problem.