Is it possible to remove a provisioning server from using a GUI, and if so how is it done?
Yes, this can be done by using an ldap browser such as Jxplorer.
Steps to achieve:
1) Connect to your provisioning server through Jxplorer (port 20389).
2) Go to the servers path found here. IM->CommonObjects->Configuration->Parameters->servers
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3) There the server(s) will be listed. If so, please export that sub tree (Servers) to an LDIF file. This can be used as a backup file. Store this in a location that can be easily remembered.
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4) Then highlight the Server you would like to remove, and click on Edit and select delete. Do the same for any additional servers you would like to remove.
5) Relaunch the Provisioning Manager and verify if the removed machines are no longer listed.