Image Processing Extension working in AP but not on Server

Dear KNIME team,

we’re seeing a strange issue after recently installing KNIME Server 4.11.2 and also reinstalling an executor (KNIME 4.2.2). While executing workflows on the server (both from KNIME AP and via the WebPortal) works fine in general, I get exceptions like this when trying to run workflows that contain any node from the KNIME Image Processing extension:

Errors loading workflow ‘Image Processing Extension’ due to missing extensions:

Extension: KNIME Image Processing
Nodes: Image Generator, ImgPlus to PNG Images

Together with our systems admin, we checked if we can start up KNIME AP on the executor instance directly (it’s running on a CentOS virtual machine), and the workflows are running fine when started from the GUI.

Also, the extensions are reported to be installed correctly, in particular:
All installed features
$ ./knime -application org.eclipse.equinox.p2.director -nosplash -consolelog -lir -d $PWD
CompilerOracle: exclude javax/swing/text/GlyphView.getBreakSpot
Operation completed in 641 ms.

Would you have any idea why the KNIME Image Processing extension would be missing when running from KNIME Server? Is there anything else I can check?

(I also ran a workflow containing the Extract System Properties node to check that that the executor is running from the correct folder etc.)

Thanks in advance for any advice.

Hi @imagejan,

Sorry for asking the obvious: Does this workflow have other nodes from the KNIME Image Processing extension, as in, does it complain about all nodes in the workflow?

Is the executor started as a service? What does the invocation look like, i.e. what’s the output of ps aux for the knime binary?

Best regards,

Sorry I wasn’t clear here. Yes, it complains about all image processing nodes in the workflow.
The test workflow I was using contained just these two nodes, actually.

As far as I can tell, no, i.e. we didn’t install the executor service for (potentially) multiple executors. Is that a requirement for extensions to work correctly? (Workflows containing other nodes executed without problems on the server.)

I will check back when I have direct access to the server machine, and will follow up here.

Definitely not. It’s just an additional layer step where something can go wrong (e.g. which user is executing the service) that I wanted to exclude from the investigation.

Another question: Did you, by chance, copy in the knime.ini from a previous installation?

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