3.3 Web-based system administration (Webmin)

Webmin is a Web-based system administration tool for most UNIX systems. You need a frame-capable browser with Java support (this is only required for some modules).

Webmin has a modular structure it is easy to customize. Webmin has a built-in ability to delegate administration tasks to non-root users.

3.3.1 Webmin installation

To install Webmin, download the tar.gz file from:

http://www.webmin.com

Uncompress and untar it to the /opt directory.

Run the setup.sh script and answer the dialogs as shown in Figure 3-2.

Important

In a production environment, we recommend that you enable ssl support and use secure password (keep in mind that the main webmin user has all the root privileges!).

Example 3-2. Webmin installation

 lpar3:/opt/webmin-1.120 #  ./setup.sh  *********************************************************************** *            Welcome to the Webmin setup script, version 1.120        * *********************************************************************** Webmin is a web-based interface that allows Unix-like operating systems and common Unix services to be easily administered. Installing Webmin in /opt/webmin-1.120 ... *********************************************************************** Webmin uses separate directories for configuration files and log files. Unless you want to run multiple versions of Webmin at the same time you can just accept the defaults. Config file directory [/etc/webmin]: Log file directory [/var/webmin]: *********************************************************************** Webmin is written entirely in Perl. Please enter the full path to the Perl 5 interpreter on your system. Full path to perl (default /usr/bin/perl): Testing Perl ... Perl seems to be installed ok *********************************************************************** Operating system name:    SuSE Linux Operating system version: 8.1 *********************************************************************** Webmin uses its own password protected web server to provide access to the administration programs. The setup script needs to know :  - What port to run the web server on. There must not be another    web server already using this port.  - The login name required to access the web server.  - The password required to access the web server.  - If the webserver should use SSL (if your system supports it).  - Whether to start webmin at boot time. Web server port (default 10000): Login name (default admin): Login password: Password again: Use SSL (y/n): n Start Webmin at boot time (y/n): y *********************************************************************** Creating web server config files.. ..done Creating access control file.. ..done Inserting path to perl into scripts.. ..done Creating start and stop scripts.. ..done Copying config files.. ..done Configuring Webmin to start at boot time.. Created init script /etc/init.d/webmin ..done Creating uninstall script /etc/webmin/uninstall.sh .. ..done Changing ownership and permissions .. ..done Running postinstall scripts .. ..done Attempting to start Webmin mini web server.. Starting Webmin server in /opt/webmin-1.120 ..done *********************************************************************** Webmin has been installed and started successfully. Use your web browser to go to   http://lpar3:10000/ and login with the name and password you entered previously. 

Now we point our Web browser to:

 http://lpar3.residency.local:10000/ 

We log in as admin with the password we provided, as shown in Figure 3-1 on page 103.

Figure 3-1. Webmin administration screen

3.3.2 Using Webmin

By selecting Webmin Users , we can create dedicated Webmin users and assign the Webmin modules to them. This allows us to have, for example, a user who is only allowed to manage printers through the Webmin interface.

Webmin is also cluster-aware, so we can install it on different nodes and run cluster commands from one central administration point, and run scripts or create users on all nodes in the cluster.

Not all Webmin modules worked properly on our system; some missed some prerequisites, and others failed to complete the task. We recommend that you test each module that you want to use on a test system. However, Webmin does provide action logs with detailed descriptions of which Webmin user has issued which command.