nfsidmap(5)                                                                                                          nfsidmap(5)



NAME
       nfsidmap - The NFS idmapper upcall program

DESCRIPTION
       The file /usr/sbin/nfsidmap is used by the NFS idmapper to translate user and group ids into names, and to translate user
       and group names into ids. Idmapper uses request-key to perform the  upcall  and  cache  the  result.   /usr/sbin/nfsidmap
       should  only  be called by request-key, and will perform the translation and initialize a key with the resulting informa-
       tion.

       NFS_USE_NEW_IDMAPPER must be selected when configuring the kernel to use this feature.

CONFIGURING
       The file /etc/request-key.conf will need to be modified so /sbin/request-key can properly direct the upcall. The  follow-
       ing line should be added before a call to keyctl negate:

       create    nfs_idmap *    *    /usr/sbin/nfsidmap %k %d 600

       This  will direct all nfs_idmap requests to the program /usr/sbin/nfsidmap The last parameter, 600, defines how many sec-
       onds into the future the key will expire.  This is an optional parameter for /usr/sbin/nfsidmap and will default  to  600
       seconds when not specified.

       The idmapper system uses four key descriptions:

              uid: Find the UID for the given user
              gid: Find the GID for the given group
             user: Find the user name for the given UID
            group: Find the group name for the given GID

       You  can  choose to handle any of these individually, rather than using the generic upcall program.  If you would like to
       use your own program for a uid lookup then you would edit your request-key.conf so it looks similar to this:

       create    nfs_idmap uid:*     *    /some/other/program %k %d 600
       create    nfs_idmap *         *    /usr/sbin/nfsidmap %k %d 600

       Notice that the new line was added above the line for the generic program.  request-key will find the first matching line
       and run the corresponding program.  In this case, /some/other/program will handle all uid lookups, and /usr/sbin/nfsidmap
       will handle gid, user, and group lookups.

AUTHOR
       Bryan Schumaker, <bjschumaATnetapp.com>



                                                         1 October 2010                                              nfsidmap(5)