NAME

nss_ndb - BerkeleyDB nsswitch backend for passwd and group data

DESCRIPTION

The nss_ndb nsswitch backend is a shared library that enables usage of BerkeleyDB btree database files as a backend for passwd and group data. It is tuned to be fast and efficient for large installations (>100,000 entries in passwd & group databases) and handle users being member of many groups efficiently.

CONFIGURATION

First make sure there is a symbolic link from /usr/lib/nss_ndb.so.1 to the real location of the nss_ndb.so.<version> library.

Second step is to populate the databases in the /var/db/nss_ndb/ directory.

Third step is to activate the use of nss_ndb in the /etc/nsswitch.conf file by adding the ndb keyword on the passwd and group lines

Depending on how nss_ndb was built support for a configuration file and/or a configuration environment variable (by default NSS_NDB_CONFIG) may (but normally isn't) have been enabled. The environment variable is probably mostly useful for debugging purposes and uses the same options as the configuration file but are specified as a comma-separated list of key:val pairs. For details of the configuration file see: nss_ndb.conf(5)

You can check if nss_ndb was built with support for a configuration file and/or variable by:

$ strings /usr/lib/nss_ndb.so.1 | fgrep nss_ndb.conf
$ strings /usr/lib/nss_ndb.so.1 | fgrep NSS_NDB_CONFIG

DATABASE

The databases are normally stored in /var/db/nss_ndb and can be populated via the makendb tool from text files.

A more efficient way is to use a sync tool to update the local NDB databases from a remote source regularily (like a MySQL server, or an AD or LDAP server). An example sync tool talking to a MySQL server written in Perl is available as ndbsync(8) which can be modified for your purposes. If you write your own - make sure you do not forget to lock (using flock (2)) the databases before updating them in order to maintain consistency.

All tables use UTF-8. All values include a terminating NUL character and have the following format:

passwd.byname: Key: user-name
Data: user:password:uid:gid:class:change:expire:gecos:home:shell
passwd.byuid: Key: uid
Data: user:password:uid:gid:class:change:expire:gecos:home:shell
group.byname: Key: group-name
Data: group:password:gid:user,user,user,...
group.bygid: Key: gid
Data: group:password:gid:user,user,user,...
group.byuser: Key: user
Data: user:gid,gid,gid,...

EXAMPLES

passwd.byname:
  Key:
    anna
  Data:
    anna:*:1000036:1000000::0:0:Anna Andersson:/home/anna:/bin/sh^@
passwd.byuid
  Key:
    1000036
  Data:
    anna:*:1000036:1000000::0:0:Anna Andersson:/home/anna:/bin/sh^@
group.byname
  Key:
    wheel
  Data:
    wheel:*:0:root,peter,mike,john,anna^@
group.bygid
  Key:
    0
  Data:
    wheel:*:0:root,peter,mike,john,anna^@
group.byuser
  Key:
    anna
  Data:
    anna:1000000,0,101,102^@

FILES

/usr/local/share/examples/nss_ndb/ndbsync
/var/db/nss_ndb

AUTHOR

nss_ndb and tools was written by Peter Eriksson <pen@lysator.liu.se>.