[HTCondor-users] how to upgrade producing less damage as possible

[Gianmauro Cuccuru <gmauro@xxxxxxxxxxxxxxxxxxxxxxxxxx>]

We have a HTCondor cluster using version 8.8.12, and I want upgrading it 
to version 8.8.15.
Execute nodes are VMs, while the central manager and the submit node are 
physical machines.
I can drain execute nodes to replace the image on it.

My doubts are:
* in which order the nodes should be upgraded?
* 8.8.12 and 8.8.15 nodes can coexist?
* If I stop the central manager or the submitter, running jobs will be 
broke?

Can you recommend a proper way to upgrade it?

Thanks in advance
Best
Gianmauro

--
Gianmauro Cuccuru

UseGalaxy.eu
Bioinformatics Group
Department of Computer Science
Albert-Ludwigs-University Freiburg
Georges-KÃhler-Allee 106
79110 Freiburg, Germany