3.2 To YaST or not to YaSt

Yet another Setup Tool (YaST) is the main administration instrument on a SuSE Linux distribution. It combines most common administration tasks . YaST is not distributed under the General Public License (GPL), but has its own license; see:

http://www.suse.de/en/private/support/licenses/yast.html

YaST can be used in graphical mode or in a terminal window with ncurses. It is modular and opens new windows in a graphical mode for each module. You can get the list of available modules on your system (and shortpaths) by issuing the yast2 -list command, as shown in Example 3-1.

Example 3-1. AvailableYaST modules and shortpaths

 # yast2 -list Available modules: autoyast backup bootfloppy disk dns dsl firewall hwinfo idedma inetd inst_source isdn joystick keyboard lan language ldap lilo lvm_config mail modem mouse nfs nfs_server nis nis_server online_update powertweak printer profile-manager proxy restore routing runlevel security sound sw_single sysconfig timezone update users vendor x11 

YaST is easy to use and in graphical mode, it visualizes complicated tasks in a comprehensible way. We recommend using it, for example, for partitioning, for the first setup of Logical Volume Manager (LVM), and so on. YaST will prevent you from making certain errors and at least warn you in critical cases.

YaST makes changes to the system directly; it does not maintain its own configuration database (as was the case in older versions of SuSE). This means that we can combine administration by editing appropriate configuration files and through YaST, without producing system inconsistencies. For example, if we edit /etc/resolv.conf and run yast2 dns after that, it will show the current entries and allow us to edit them.

On the other hand, we do see some disadvantages to using YaST in a network environment:

• YaST does a great deal of logging, but it does not log which files are changed and which commands are called to achieve the particular task. You can find YaST logs in /var/log/YaST2/y2log. It differs from the AIX administration tool smit it that you cannot use the information in the logs for task automation through scripting.

• YaST is a single system administration tool, so you can only change the system you are using; you cannot run the same command on different systems.

• YaST does not provide a "bash mode", so you cannot include the task that YaST should complete in the command line arguments or in a script.

• Some modules provided by YaST are incomplete; that is, they do not offer all possibilities and are restricted in functionality. For example, it is not possible to change RAID devices, to assign a whole physical disk to LVM, or to manage LDAP users through YaST.

Tip

We used tripwire to find out which files YaST is changing. To use tripwire, you need to generate a tripwire database first, then do anything with YaST and run tripwire again to see which files are changed