We have a requirement to support large number of superusers. (users who impersonate as another user) (http://hadoop.apache.org/docs/r1.2.1/Secure_Impersonation.html)
Currently each superuser needs to be defined in the core-site.xml via proxyuser settings. This will be cumbersome when there are 1000 entries.
It seems useful to have a pluggable mechanism to specify proxy user settings with the current approach as the default.