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teemusalo
New Contributor II

Load balancing blocks data connections list

Hello,

recently we updated our load balancing rules to allow only certain streams on a certain rim node.

Everything worked as expected until we needed to modify our data connections in one of our applications data load editor.

There are a few post about the "Spinning data connections" (like this ) but the question goes unanswered and does not seem to relate to this next happening.

The data connections list does indeed keep spinning in our application and the browser console outputs the following error:

api/dataprepservice/v1/apps/<applicationID>/model/current:1

Failed to load resource: the server responded with a status of 500 (Internal Server Error)


What this error is, we have no idea. But what we did find out is what causes it.

Accessing data load editor through an app on our central node, that is load balanced to only show on central node, blocks the data connections list from rendering successfully.

When accessing an app that is also accessible on our rim node, the data connections list renders without problem.

I was able to recreate this problem multiple times by allowing all applications on both nodes and voilá, the data connections render.

Now this causes a problem, because we want to filter certain apps from being loaded on our rim node, but the only way to render the connections list requires the app to be available on both.

What we also did try was to use different resource filters (DataConnection*. App.DataSegment* etc.) in our load balancing rules but the only one that had the desired effect was to allow resource App* or App_* on rim node.

Has anyone encountered this problem before or have any idea how to fix/go around it?

All the data connections are accessible on our QMC, tasks and such, even though they do not render as a list in data load editor, so this must not be an ODBC or some like problem.

Also, we are using Qlik Sense Server with June 2018 version.

We did also try booting up the server.

Your help and wisdom is much appreciated,

Teemu

1 Solution

Accepted Solutions
teemusalo
New Contributor II

Re: Load balancing blocks data connections list

Hey,

for anyone encountering similar problems, this is how i solved my problem:

From QMC virtual proxies I removed the rim node from the load balancing nodes. This seems to have reset the balancing rules somewhere behind the mighty jungle that is Qlik Sense server.

For some unknown reason, some of my calls to the server seems to have been directed by the load balancing rules to the rim node (api/dataprepservice/v1/apps/<applicationID>/model/current referred by the applicaton page).


This caused some weird situation, where I could see the apps that I was supposed to but some calls were blocked with an error in the console "app not found" which caused an internal server error also.

I did add the rim node back to the load balancing nodes and everything still works.

regards,

Teemu

2 Replies
teemusalo
New Contributor II

Re: Load balancing blocks data connections list

Hey,

for anyone encountering similar problems, this is how i solved my problem:

From QMC virtual proxies I removed the rim node from the load balancing nodes. This seems to have reset the balancing rules somewhere behind the mighty jungle that is Qlik Sense server.

For some unknown reason, some of my calls to the server seems to have been directed by the load balancing rules to the rim node (api/dataprepservice/v1/apps/<applicationID>/model/current referred by the applicaton page).


This caused some weird situation, where I could see the apps that I was supposed to but some calls were blocked with an error in the console "app not found" which caused an internal server error also.

I did add the rim node back to the load balancing nodes and everything still works.

regards,

Teemu

amien
Valued Contributor

Re: Load balancing blocks data connections list

"From QMC virtual proxies I removed the rim node from the load balancing nodes. This seems to have reset the balancing rules somewhere behind the mighty jungle that is Qlik Sense server."


I had the same issue. I only added my rim nodes to the virtual proxies load balancing nodes. I added the central node and now it works fine.


issue is back again. seems like restart of the virtual proxy only works temporary