You need to make sure the user has su/sudo permissions at the operating system level. On Windows, the agent process should run as LocalSystem or admin.
https://www.ibm.com/support/knowledgecenter/SS4GSP_6.2.7/com.ibm.udeploy.doc/topics/arch_appx_sudo_using.html
https://www.ibm.com/support/knowledgecenter/SS4GSP_6.2.7/com.ibm.udeploy.doc/topics/arch_appx_impersonation_windows.html
You can also set a default impersonation for a resource:
https://www.ibm.com/support/knowledgecenter/SS4GSP_6.2.7/com.ibm.udeploy.doc/topics/resources_impersonation.html