# Ondemand server supporting clusters with different OS?

**URL:** <https://discourse.openondemand.org/t/ondemand-server-supporting-clusters-with-different-os/2512>\
**Category:** General Discussion\
**Tags:** question\
**Created:** [March 3, 2023, 6:02pm UTC](https://discourse.openondemand.org/t/ondemand-server-supporting-clusters-with-different-os/2512 "2023-03-03T18:02:14Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![emily.dragowsky](https://avatars.discourse-cdn.com/v4/letter/e/c68b51/32.png) [@emily.dragowsky](https://discourse.openondemand.org/u/emily.dragowsky)\
**Post date:** [March 3, 2023, 6:02pm UTC](https://discourse.openondemand.org/t/ondemand-server-supporting-clusters-with-different-os/2512/1 "2023-03-03T18:02:14Z")

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We’re engaged in a migration of our compute nodes to RHEL 8 from RHEL 7. I’ve been studying the docs, but remain unclear whether there would be a problem having a single Ondemand host supporting clusters running different OS.

On the one hand, the ood server needs configured to support the scheduler, and otherwise function as a login node. This requirement seems to be a barrier to implementation.

On the other, I’ve read where the same ood server supports clusters with different schedulers.

Therefore, I appeal to the group for thoughts.  
And I apologize if I’ve missed previous discussions on this/similar topic(s).

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**Author:** ![jeff.ohrstrom](https://sea1.discourse-cdn.com/flex015/user_avatar/discourse.openondemand.org/jeff.ohrstrom/32/136_2.png) [@jeff.ohrstrom](https://discourse.openondemand.org/u/jeff.ohrstrom)\
**Post date:** [March 3, 2023, 6:09pm UTC](https://discourse.openondemand.org/t/ondemand-server-supporting-clusters-with-different-os/2512/2 "2023-03-03T18:09:05Z")

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It can, really it doesn’t matter so much to OOD itself.

What you’ll have issues with is the apps. Specifically VNC apps that use XFCE - See these topics below. We’ve made some headway on this issue (both myself and the original posters) - but I don’t think it’s 100% resolved.

> [@Problems with interactive Matlab app window](https://discourse.openondemand.org/t/problems-with-interactive-matlab-app-window/2476):
>
> Hello, I’m having trouble getting the expected behavior with the window in a Matlab interactive app. Any help or ideas would be greatly appreciated! My problem appears similar to the issue described in [Matlab window problem](https://discourse.openondemand.org/t/matlab-window-problem/2294): the standard window features don’t work, i.e. the window won’t resize, min/max/close buttons are missing. However, I’m seeing different errors in the log. I’m using a simplified version of OSC’s script.sh.erb from the [OSC/bc\_osc\_matlab GitHub repo](https://github.com/OSC/bc_osc_matlab/blob/master/template/script.sh.erb): #!/usr/bin/env bash # …

> [@App doesn't have desktop background](https://discourse.openondemand.org/t/app-doesnt-have-desktop-background/2493):
>
> I’ve got two ondemand systems, an old one and a new one. The old one is version 1.6.25-1.el7, the new one is 2.0.29-1.el8. I’m trying to get the new one setup and running. I copied over my RStudio app that lives in /var/www/ood/apps/sys/RStudio and adjusted names so that it works. But when I launch it on the new version I don’t get a resizable window on a desktop Does anyone know how to get the desktop on the ne…

Basically the TLDR is that XFCE updated from 12 to 14 and has some compatibility issues with the way all our scripts are written.

We haven’t updated our own apps, so it’s not 100% solved but we’ve at least reduced the problem space a bit. In any case - you’ll likely have to modify some of the VNC app scripts so that they can recognize whether they’re on REHL 7 or 8 and act accordingly.

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**Author:** ![emily.dragowsky](https://avatars.discourse-cdn.com/v4/letter/e/c68b51/32.png) [@emily.dragowsky](https://discourse.openondemand.org/u/emily.dragowsky)\
**Post date:** [March 3, 2023, 6:15pm UTC](https://discourse.openondemand.org/t/ondemand-server-supporting-clusters-with-different-os/2512/3 "2023-03-03T18:15:35Z")

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Thanks, Jeff –

This is very helpful. My thought is to have a redundant server that can backup either of our production servers – supporting only RHEL 8 or 7. I’ll give your comments, the discussions and the VNC app scripts some attention, and report back.

Cheers