Tutorial: Windows to Linux: Part 1 Introduction to Webmin

A browser-based management tool

Level: elementary

Chris Walden (cmwalden-at-us.ibm.com)
E-commerce architect, IBM developer relations
January 2004

IBM e-commerce architect Chris Walden willDeveloperWorksThe nine articles published in this article will guide you how to use your Windows Operating Skills in Linux. This section describes how to install and use Webmin. It is a browser-based management tool that can be applied to Linux and other platforms. It provides a graphical interface that can complete many management and operation tasks.

One of the challenges from Windows Environment Management to Linux environment management is that you need to learn to use new tools. As an administrator, you want to understand the details of the operating system to maximize its effectiveness. However, when you are still in the learning stage, you need to complete the specific work.

To speed up your Linux operation, we will install a program called Webmin. As webmin.com (see the link in reference) says: "Webmin is a Web-based UNIX system management interface. With any browser that supports tables and forms (and the Java required by the File Manager module), you can set user accounts, Apache, DNS, file sharing, and so on. Webmin includes a simple web server and many CGI programs that can directly modify system files, such/etc/inetd.confAnd/etc/passwd. The Web server and all CGI programs are written in Perl 5 without any non-standard Perl modules ."

Webmin can actually run on all UNIX-like platforms, including Linux, Aix, HPUX, Solaris, OS X, and so on. It has a Web Front-end that can complete many management tasks in Linux. It can run locally or remotely in any graphical browser. Webmin uses SSL to ensure security and prevent listening. When you learn about Linux management, Webmin will save you a lot of time. Webmin can also help you complete tedious tasks that cannot be automatically executed.

Webmin is extensible. The author provides a development wizard, and some third-party modules have emerged. You can also design your own modules so that Webmin can always be adjusted as needed.

Install Webmin
The first step to use Webmin is to install Webmin. Webmin has been included in a few release versions, but it is also very easy to download from the Webmin website (see the link in references ).

At the time of writing this article, the latest version of Webmin is 1.90. The correct installation methods vary according to the Linux release version you are using. If you are using a Red Hat Linux or unitedlinux release version (Suse, Turbo, connectiva, or caldear), the simplest is to use the RPM installation method. If you are using another release version, you need to read your release version documentation and Webmin installation instructions to select the best installation method. We assume that the installation is based on RPM.

First, check whether Webmin is installed on your system. Enter:

rpm -q webmin

If Webmin has been installed on your system, you will get the following version:

Webmin-1.090-1

Otherwise, you will see the prompt that Webmin is not installed:

package webmin is not installed

Install software package In Linux, the installation of most software packages is as simple as installing Webmin in this article. For more information about installing and downloading software packages-or even compiling applications from source code-see section 9th of this series of articles.

Even If Webmin has been installed, its version may be earlier than the latest available version. In this case, you can use the following command to upgrade or reinstall it:

rpm -Uvh webmin-1.090-1.noarch.rpm

When a lengthy update is performed, a progress bar with the # mark is output.

RPM noarch You will notice that Webmin is listed as the "noarch" software package. Since RPM is a binary file, they are usually compiled for a specific architecture, such as i386 or ppc. Installing a software package on the wrong architecture may result in incorrect results. Because Webmin is written in Perl, and Perl is unrelated to the architecture, Webmin is identified as "noarch ".

After Webmin is installed, it is enabled by default. However, this installation does not enable SSL. SSL requires the installation ofNet::SSLeay. If this module is not installed, Webmin is secure only when running from the local console. At the end of this article, we will briefly introduce the secure use of Webmin.

Practical Extraction and Reporting Language (Perl) Perl is a multi-platform explanatory programming language that emerged in 1987. It can be used on a variety of platforms, including Windows, with sophisticated script functions. Perl's strength lies in text processing and is widely used in Web CGI programming. Perl can be extended by adding modules. These modules are actually function libraries written in Perl. Most modules, including Perl itself, can followThe Artistic LicenseThis license is freely available (see the links in references ).

Use Webmin
Use your favorite web browser to access Webmin. The file browser and the Telnet/ssh client are based on the applet. You must install Java Runtime Environment on your browser. These two tools will bring convenience, but they are not indispensable. All other modules have no special requirements.

Point your browser to system port 10000 to start using Webmin. In the browser of the local system, you should enterhttp://localhost.localdomain:10000/. First, you will see a logon interface.

Webmin users are separated from operating system users. This allows you to set users for management through Webmin without passing through the conventional Unix authentication mechanism. However, if you want some users to use Webmin, you can add them to the Webmin user list and allow Webmin to verify it using Unix tools, instead of using the Wemin internal verification mechanism. Each user can access the Webmin module. For example, a Helpdesk employee can only use the password function, while other employees can access all modules.

After the installation is complete, the root user is automatically created and the password is the system's root password. Webmin records logs based on logon records. In this way, an administrator group with root user permissions may be created in a multi-Administrator environment, create users for each user using the system. You must log on as root for the first time.

Root User In Linux, the primary administrator user isRoot. The root user has full control over the entire system. Root cannot be abused.

Webmin form
The first screen you see will be the Webmin Configuration Section. Here you can configure Webmin users, configuration modules, and view activity logs. The icon on the top can be switched between different module forms in Webmin. All modules are configurable. You can reorganize them as needed.

Figure 1. Webmin configuration screen

You can also use Webmin There is an icon used to configure the optional Usermin package. This package provides a Web-based tool that allows you to perform tasks such as changing passwords and managing system emails. Usermin cannot access the system configuration file. Both Usermin and Webmin are free products.

SystemForm allows you to configure the overall operating system. Here, you can configure file systems, users, groups, and Common System Bootstrap actions. You can control the services running in the system. You can select the Bootup and Shutdown icons to determine whether they are automatically started. However, the specific configurations of those services are completed by the Servers form. Pay special attention to the "Software Package" tool, which allows you to conveniently view installed Software packages in your system, as well as interfaces to the release version upgrade library and rpmfind.net, rpmfind.net is a public RPM library on the Internet (see references ).

ServersForm allows you to configure various services that may run in the system. BIND and DHCP tools are very convenient. At the same time, the Samba tool is also very useful for sharing configuration files and printers between Windows and other clients. The SMTP server Sendmail is famous for its extremely complex configuration files. The Webmin Sendmail tool also solves this problem for you.

Figure 2. Webmin server screen

NetworkingThe tools provided by the form can be used to configure network hardware and perform some complex network control, such as firewall. All tools need to modify the standard configuration file, so any work you do in Webmin can be done by the corresponding console tool.

HardwareForm is used to configure physical devices, mainly printers and storage devices. It is particularly worth noting that the Logical Volume Management (LVM) tool can help you visually manage dynamic volumes on your Linux system.

ClusterTools in the form are used to manage the cluster system.ClusterThis refers to a group of related systems whose configurations need to be synchronized. The system can synchronize user, group, software package, and other configurations during system fault detection. These tools help you build a hot error recovery system and other systems that need to be synchronized. A cluster is an advanced topic. You may need to install some software packages that are not included in your Linux release.

OthersThere are various tools in the form, and you may find them useful. The "SSH/Telnet Login" and "File Manager" tools require applet support and can be run only after JRE is installed on your browser. The Perl Modules tool keeps you up with the development of the Perl module, which can be directly connected to CPAN on the Internet. The File Manager tool provides a browser-like view for the File system on the server. If you are working remotely, you can move and copy files without using the memory of your workstation. The "SSH/Telnet Login" tool is a remote shell console that allows you to access the console through a browser.

Conclusion
Webmin is a browser-based management application written in Perl. Webmin is extensible and can be used in Linux and other Unix-like operating systems. After the installation is complete, you can enter Webmin on a local or remote browser through a specific port, usually 10000. It has an interface that can point to and click to complete various Linux management tasks, including user management, network firewall and network device configuration.

Webmin is free to install and use. It is a good tool for Linux environment management. If you used a Windows Graphical management tool before. The Webmin tool is a front-end tool based on the console. Therefore, the configuration effects of the two tools are consistent. Both tools can perform management tasks reliably.

References

• Read Other sections of the Windows to Linux journey series (DeveloperWorks, January 1, November 2003 ).

• View the Webmin homepage for an overview of this tool and download the Webmin tool.
• Before using Webmin remotely, read Securing Webmin with SSL.
• Go to Perl.org to learn more about Perl.
• CPAN has many useful Perl modules and similar software.
• Perl is freely released following the Artistic License. You can make public changes to its source code.OrPrivate.
• Through IBMDeveloperWorksThe Cultured Perl column gives you a deeper understanding of Perl and its development.
• RPMFind is an RPM library, where you can find many useful (and many useful but interesting) programs.
• "Understand the Linux configuration file "(DeveloperWorks) Explains user permissions, background processes, and services.
• "Using xinetd programs for System Management" and "using Perl to automate UNIX System Management" describes other ways to simplify your system management. Similar content is also involved in "Real-Time Linux management.
• Useful tutorials include: "LPI certification 101 (release 2) exam prep, Part 2: Basic administration" describes shell pipelines and text processing commands; "LPI certification 101 (release 2) exam prep, Part 3: Intermediate Administration describes documents, user account management, and authorization; "LPI certification 101 (release 2) exam prep, Part 4: advanced administration introduces file systems and system logs.
• To start using IBM software on Linux, speeding up your Linux application development will provide you with the best reference materials. You can find installation tips and references for various applications such as DB2, Lotus Domino, WebSphere Application Server, and WebSphere Studio. You can also log on to get the free Linux Software Evaluation Kit, which contains trial Software and training materials.
• InDeveloperWorksYou can find more references for Linux developers in the Linux area.

About the author Chris Walden is an IBM Developer Relations Technical Consulting (also knownDragonslayersE-commerce architect, which provides education, implementation, and consulting for IBM business partners. He is dedicated to Linux-related work and will publicize the benefits of Linux to people around him as soon as he has the opportunity. In addition to fulfilling the responsibilities of his architect, he is also proficient in various fields of Linux infrastructure servers, including files, printing and other application services in the hybrid platform user environment. Chris has 10 years of experience in the computer industry. From field support to Web application development and consulting, he has been involved in various fields. You can contact Chris via cmwalden-at-us.ibm.com.