9.4.3. Overriding or Augmenting Site Configuration Files
It can be useful to override site defaults for a specific mount point on a client system. For example, consider the following conditions:
- Automounter maps are stored in NIS and the
/etc/nsswitch.conffile has the following directive:automount: files nis
- The
auto.masterfile contains the following+auto.master
- The NIS
auto.mastermap file contains the following:/home auto.home
- The NIS
auto.homemap contains the following:beth fileserver.example.com:/export/home/beth joe fileserver.example.com:/export/home/joe * fileserver.example.com:/export/home/&
- The file map
/etc/auto.homedoes not exist.
Given these conditions, let's assume that the client system needs to override the NIS map
auto.home and mount home directories from a different server. In this case, the client will need to use the following /etc/auto.master map:
/home /etc/auto.home +auto.master
The
/etc/auto.home map contains the entry:
* labserver.example.com:/export/home/&
Because the automounter only processes the first occurrence of a mount point,
/home will contain the contents of /etc/auto.home instead of the NIS auto.home map.
Alternatively, to augment the site-wide
auto.home map with just a few entries, create an /etc/auto.home file map, and in it put the new entries. At the end, include the NIS auto.home map. Then the /etc/auto.home file map will look similar to:
mydir someserver:/export/mydir +auto.home
Given the NIS
auto.home map listed above, ls /home would now output:
beth joe mydir
This last example works as expected because
autofs does not include the contents of a file map of the same name as the one it is reading. As such, autofs moves on to the next map source in the nsswitch configuration.
