It’s time for another of our periodic dispatches from the YaST trenches. But instead of the usual collection of topics, this time we want to focus on a single feature that is finally landing in openSUSE Tumbleweed after a couple of months of development. The fun thing is that, despite all the hard work, it is a pretty unnoticeable feature for most end users.

Managing Local Users is not that Simple

The fact is that historically YaST has not relied on useradd and similar tools to create, modify and delete users and groups. Instead, it used to perform by itself all the changes in the system like creating the home directories, assigning ids or modifying the files /etc/passwd, /etc/groups, etc.

You may think management of users and groups has not changed much in Linux over time. After all, we still use the traditional Unix approach to manage local users. But the reality is that, since the birth of YaST, useradd has changed a lot:

• It was totally rewritten in the jump from (open)SUSE 11 to (open)SUSE 12, the implementation of useradd traditionally available in the package pwdutils was replaced by an alternative one in the package shadow.
• It changed the way the skeleton directories are created, with a more granular approach that copies files from several locations, not only the traditional /etc/skel.
• It added management of subuids and subgids, a feature needed for running rootless containers.
• It changed the location of its configuration, with some attributes removed from /etc/defaults/useradd, either moved to a different file or simply gone.

All those changes were incorporated to useradd and other related tools little by little without having YaST into account, so the behavior of both tools has diverged over the years. That has caused some problems in the past and could cause more in the future. So the YaST team decided it was time to close the gap.

What’s new

Starting with the version of YaST just submitted to Tumbleweed this week, YaST now relies on useradd, groupadd and other shadow tools when creating users and groups during installation and also when using AutoYaST or YaST Firstboot. We also adapted the management of the <user_defaults> section of the AutoYaST profile to make it consistent with recent versions of useradd. The changes in that area imply dropping support for some attributes like <groups>, <no_groups> and <skel>. See the description of this pull request for the rationale and historic background of each change.

As some kind of developer-oriented bonus tracks, it’s also worth noticing that YaST now offers a new object-oriented API to read and manage local users (so-called Y2Users) and makes use of a new mechanism to report errors to the user (Y2Issues, which is in process of adoption in other parts of YaST as well).

What Comes Next

As mentioned, the changes affect the installation process, AutoYaST and YaST Firstboot. But the old code is still in place if you run the interactive YaST module to manage users and groups or the (not exactly fully maintained) command line interface of YaST. We plan to connect those two with the new implementation in the following weeks, so the user experience is fully consistent for all possible usages of (Auto)YaST.

Of course, the new implementation opens the door for deeper changes affecting the YaST user interface or the management of non-local users (LDAP, Samba, NIS…). But to be honest we do not plan to go that far in the mid term. We plan to focus our firepower on other goals, now that the threat caused by the inconsistency in the user management tools is under control.

More News to Come

Of course we have worked in many other areas during the past sprint and we will continue doing so in the future ones. So will be back soon with more news and likely with a more standard post covering several topics. So stay tuned and see you in a couple of weeks!