nsscache is a Python library and a commandline frontend to that library that synchronises a local NSS cache against a remote directory service, such as LDAP.

As soon as you have more than one machine in your network, you want to share usernames between those systems. Linux administrators have been brought up on the convention of LDAP or NIS as a directory service, and /etc/nsswitch.conf, nss_ldap.so, and nscd to manage their nameservice lookups.

Even small networks will have experienced intermittent name lookup failures, such as a mail receiver sometimes returning "User not found" on a mailbox destination because of a slow socket over a congested network, or erratic cache behaviour by nscd. To combat this problem, we have separated the network from the NSS lookup codepath, instead using an asynchronous cron job and a glorified script, improving the speed and reliability of NSS lookups. We presented a talk at linux.conf.au 2008 on the problems in NSS and the requirements for a solution.

Here, we present to you this glorified script, which is a little more extensible than

ldapsearch | awk > /etc/passwd

Read more about the motivation behind this tool.

Latest Version

The latest version is 0.8.8. Read the Release Notes here, and here for installation instructions.