Is there a "proper" or at least unofficially semi-supported way of running custom scripts triggered by a scheduler like the OneFS job engine or cron directly in an Isilon/PowerScale cluster? 

Some very old information (2013 and older) points towards putting custom .sh scrips in either /root or /ifs and triggering them via cron on one of the nodes...

In one of our environments (security hardened PowerScale tennant/access zone network)  there are several use cases where running file and data management tasks (move, rename, copy, delete files/folders and also "selective smartlock" certain filetypes within some folders where other filetypes and/or subfolders must not be smartlocked) would be best triggered and executed from within the cluster, instead of having to allow some sort of external control/management station manipulate the data.