To manage a server with Webmin, you need to install Webmin Web server on that computer. Once installed, it allows you to manage your server over the Web through an easily accessible HTML interface. You can install Webmin for several Unix- and Linux-like operating systems, including important Linux distributions such as Red Hat, SUSE and Ubuntu, and Unix versions such as HP/UX, Sun Solaris and IBM AIX; even Mac OS X is supported.
Support for different Linux and Unix systems in Webmin is important, as differences exist between the way these systems handle configuration. The name of a specific configuration file or how a service is set up might be different between distributions. Therefore, support for your distribution of choice is important. This ensures that no conflicts will occur between the way your distribution handles certain configuration issues and the method used by Webmin. See this list for all of Webmin's supported systems.
Installing the Webmin agent on your servers is easy. Just download the installation package for your distribution. Different formats are available, such as .dpkg, .rpm, .tar files and Solaris packages. Just pick the package of your choice and complete the easy installation. After you install Webmin, it will be waiting for you at SSL port 443.
Webmin functionality and additional modules
Out of the box, Webmin offers you basic functionality, which allows you to perform most of the important tasks that administrators typically want to perform on Linux, such as monitoring processes and creating users.
But service-related tasks are available. The number of service-related tasks that are installed by default is rather limited: mail, Samba, SSH and Squid. If you need to perform tasks on other services, you'll need to add additional modules, of which lots are available through the Webmin website.
Working with modules makes Webmin strong. The modular concept allows developers to write plug-ins to virtually anything. The only limitation is the imagination of the developer, and that means that in large environments you can develop custom modules that are tailor-made to the environment you work in.
Even without adding additional modules, Webmin allows you to perform many tasks. For instance, in the hardware section you'll find programs to monitor drive status, create partitions and logical volumes on disk, manage printers, and much more. And on the networking tab you'll get access to tasks that are in most cases difficult to handle, such as bandwidth monitoring, Kerberos management, creating VPN connections and firewalling. Using these modules means that you no longer need to be able to work on the command line to manage a Linux server.
Multiple server management with Webmin
Webmin also offers options to manage multiple servers. First, you can configure Webmin to scan for new servers periodically or add new servers manually. This gives you an overview of all the available servers and an option to connect to another server in an easy way, just by clicking its link from the Webmin interface.
After finding the other Webmin servers, you can use the Webmin cluster option, which allows you to perform management tasks on multiple Webmin servers simultaneously. The Webmin cluster option (which has nothing to do with typical HA or HPC clustering) provides options to easily perform common tasks on multiple servers. Think of distributing files to many servers, installing software packages or changing a password for a user account that exists on multiple servers.
Webmin makes management of Unix and Linux in the data center easy, and it's free. Using Webmin, an administrator doesn't have to handle the sometimes-difficult command Linux to manage Linux servers. The modular architecture makes Webmin versatile -- if the functionality you require isn't included by default, you can probably add it by installing a module. Webmin also offers options to perform tasks on multiple servers, which makes it a good help to ease management of Linux, Unix and Mac OS X in your data center.
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ABOUT THE AUTHOR: Sander van Vugt is an author and independent technical trainer, specializing in Linux since 1994. Vugt is also a technical consultant for high-availability clustering and performance optimization, as well as an expert on SLED 10 administration.