The goal of Webmin’s -- a Web-based interface for Linux administration -- is to make life easier for Linux administrators and reduce the pain of everyday tasks.
When something goes wrong with a server, for example, you need to diagnose the problem and fix it in short order. With Webmin, you have easy-to-use tools at your disposal and the comfort of a Web browser to troubleshoot problems.
In this, part two of our series, we outline the basics of using Webmin for such tasks as fixing account lockout, resetting passwords and other administrative chores. In part one, we covered installing and configuring a Webmin module for general use.
Managing users and groups
If you’ve ever managed a server with multiple users, you would probably list account lockout and password reset as the two most common tasks. Webmin makes it simple to reset a user’s password or enable the account with a few mouse clicks. For servers with many users, the search tool is your friend. A single click filters the user display to those currently logged in. You can delete, disable or enable multiple users by clicking a check box beside their names and then the appropriate button.
Managing groups is just as simple. Adding users to existing or new groups only requires a few mouse clicks. Webmin will automatically create a new Group ID by default. If you are modifying an existing group, you’ll have the option of changing the group ID of files in home directories exclusively or every file in the file system.
Using Webmin for system management
Keeping a server running smoothly is probably an admin’s most important task. Most companies depend on a multitude of applications and servers to keep its businesses going. Linux servers frequently handle tasks such as user authentication using LDAP, file and print, and Web and application servers. Any one of these applications becomes mission-critical when a problem occurs. Webmin provides easy access to server and application logs, configuration files and process information to help ease the pain of troubleshooting.
One of the Webmin screens you will frequent is the System and Server Status page found under the Others tab. This page gives you a quick status on your key server applications. Webmin monitors a host of critical applications and resources on a server and then presents a health-status dashboard to indicate good and bad conditions (green checkmarks are good; red Xs are bad). You can customize display options extensively to meet your needs.
Even the best servers require periodic rebooting. The old way was to open an SSH (or Secure Shell) session, log in as root and issue the shutdown command. With Webmin, it’s a single click with an additional acknowledgement. You can also completely shut down a server, but it may be problematic to power it back up.
Before it issues the command, Webmin displays a confirmation screen to ensure that you want to shut down a server. If you click on the second button, it shuts down the system.
When a server isn’t running right, the first place every good admin looks is in the system logs. Traditionally, this involves one of two options: (1) a remote login and some command line tools such as grep or tail -- or (2) the vi editor. Webmin brings these two functionalities together and under a single page.
Using Webmin for server management
Keeping specific server applications running smoothly is also key. The Servers tab lists all active server applications with Webmin management modules loaded. You have complete control of key applications such as the Apache Web server from within Webmin. The Apache management module uses icons on its main page to help you quickly identify the areas you need to examine. You can even create per-directory options for managing permissions in specific areas you might need to provide restricted access.
If you happen to add an application to a running server, you need to let Webmin know. This is done using the Refresh modules at the bottom of the options tree. The View Module’s Logs option lets you see a log of each Webmin module and the actions taken.
If you happen to stumble on a module that needs an additional library to run, Webmin can detect that situation and take the steps necessary to download and install the missing dependency.
Making the case for Webmin
Webmin is without question one of the most useful tools available for Linux administration. The fact that it’s free could make some question its usefulness. But don’t let the price tag fool you. Using Webmin is worth the time and effort. Take the leap: Download, install and give it a spin. It might just make you enjoy all those administrative tasks you’ve put off.
ABOUT THE AUTHOR: Paul Ferrill has a BS and MS in electrical engineering and has been writing about computers for over twenty years. He's had articles published in .PC Magazine, PC Computing, InfoWorld, Computer World, Network World, Network Computing, Federal Computer Week, Information Week, and multiple websites.