Introduction

System Administration With Webmin A brief overview of new era administration tool Prepared by Henry Batula Ni Xiao Peter Greenup

3 What is Webmin? Webmin is a web-based interface for system administration for Unix/Linux. Using any browser that supports tables and forms (and Java for the File Manager module), you can setup user accounts, Apache, DNS, file sharing and so on Often considered equivalent to windows control panel

4 What is Webmin (cont’d) It is a user administration tool written by Jamie Cameron in Perl that is designed to be lightweight, functional, and easily extensible It has been translated to 14 languages at the moment It has been embraced by a number of hardware and operating system vendors as the default system administration tool(Linux-Mandrake 7.0) It is extremely portable, offering support for more than 25 different Unix/Linux Operating Systems

5 What is Webmin? (cont’d) It is very easily extended to support new features and options, due to it's open and well documented API It also happens to be a fast and easy to use tool for general Unix/Linux system administration It allows easy addition of new modules without changing any of the existing code

6 What is required A simple web server, and a number of CGI programs which directly update system files like /etc/inetd.conf and /etc/passwd. The web server and all CGI programs must be written in Perl version 5. This means that you only need a Perl binary to run it.

7 Who Webmin is For It is an excellent tool for both novice and experienced system administrators When run from a local machine, it can help new users become familiar with the capabilities of a Linux system.

8 Sections within Webmin The individual modules of webim are found in 5 different sections. Webmin System Servers Networking Hardware and Others

9 Interface of Webmin

10 Webmin modules It uses modules, which are similar to plug-ins, and easily allow you to extend the base functions of Webmin. It is divided into a number of modules that each allows to administer a single aspect of system There are Currently 127 Modules The standard modules provide a graphical interface for: Apache, Squid, Bind, NFS, man pages, Sendmail, Postfix, Samba

11 admi n Scheduled Cron JobsBIND 4 DNS Server NFS Exports Internet Services and Protocols Bootup and Shutdown ActionsDisk and Network Filesystems Samba Windows File SharingUsers, Groups and Passwords Partitions on Local DisksRunning Processes Webmin ConfigurationDisk Quotas Software Packages PPP Usernames and Passwords Webmin UsersApache Webserver Printer AdministrationBIND 8 DNS Server Sendmail ConfigurationSquid Proxy Server File ManagerNetwork Configuration DHCP ServerMajordomo List Manager Firewall Configuration Common Modules from Webmin 0.74 Modules

12 Supported Operating Systems Sun SolarisNetBSDDEC/Compaq OSF/1 Cobalt LinuxMandrake LinuxMandrake Linux Coprporate Server Caldera OpenLinux eServerBSDIBM AIX Redhat LinuxHP/UXSCO UnixWare Slackware LinuxSGI/UXSCO OpenServer SuSE LinuxCorel LinuxTurboLinux MSC LinuxLinuxPPCXlinux Cendio LBS LinuxLinux From ScratchTrustix Ute LinuxLanthan LinuxTrustix Cendio LBS LinuxFreeBSDOpenBSD Debian LinuxSGI IrixMac OS Server X Delix DLD LinuxConectiva Linux Some of Webmin supported operating systems

Installation of Webmin

14 Installation of Webmin Firstly check to see if it is currently installed. Do a search for the webmin module. Webmin is included with many linux operating systems, so may appear on an installation disk. Installation requires that Perl 5 is already installed (this is usually included with most versions of linux).

15 Installation (Cont’d) L-M animation of finding package. (you may need to wait a few seconds for the animation to start).

16 Otherwise it can be downloaded from There are a couple of different versions available, choose the one which best suits your current system. Approximate file size is 3.6 to 4MBwww.webmin.com If installing the RPM package run the command: rpm -U webmin-0.87.rpm If using the Solaris package run the following command: pkgadd -d webmin-0.87.pkg Begins with root username and password. Installation of Webmin (Cont’d)

17 Installation Checks Please wait for animation of Webmin after install. Webmin is seen as a new service in the linuxconf control panel Ktail messages shows that webmin starts automatically after install.

18 Installation Checks (Cont’d) Check the following functions for Webmin: Stop Start Restart The "messages" log will show the status. Please wait for animation.

19 Logging on Open a web browser such as Netscape or IE, on any machine with access to the server you wish to log onto. Browse to the port of the IP address or hostname. (as shown below)

20 Logging on (Cont’d) Animation of logging onto the service.

Example Modules A brief description of some of the commonly used modules.

22 Webmin main tab

23 Webmin Configuration This section give the user control of the webmin setup. Allowing the adjustment to the following areas. IP address control Password settings Interface control Language used Modules included

24 Webmin Configuration (Cont’d) Animation of access to IP address

25 System Tab

26 System modules Bootup and shutdown as name suggests Users and Groups displays all users names, id’s home directory etc. allows editing of user settings Manual Pages extensive help pages

27 System modules (Cont’d) Cron Jobs This is one process that is greatly simplified by the webmin interface. Cron is a daemon that runs constantly on most unix machines. Allows for the scheduling of processes to be run at set times eg. backups or scans. Lists all scheduled jobs Control access of users to cron jobs Add a new scheduled item

28 System modules (Cont’d) Cron job screen sample

29 System modules (Cont’d) Software packages View all installed packages Search for installed packages Install new packages

30 System modules (Cont’d) Install package screen sample

31 System modules (Cont’d) FileSystem Management It provides permission to mount, dismount, create, edit, and delete 14 different filesystems To get started, click the Disk and Network Filesystems Webmin displays a list of available filesystems

32 System modules (Cont’d) File System Management Display screen will show the mount point, filesystem type, device or location whether it is mounted, and listed in /etc/fstab. To edit one of the listed file system, click its mount point, listed in the first column

33 System modules (Cont’d) File System Management To add or create a new filesystem, first select its type from the drop-down list box then click the “Add” button The Create Mount and the Edit Mount screens are similar except that it has to be filled it out Select the “Don't Save” button to prevent an entry for the swapfile from being added to /etc/fstab the swapfile will be named, imaginatively, /tmp/swapfile Click the “Create” button to activate the changes

34 System modules (Cont’d) The display screen After making changes, click the “Apply” button to update the /etc/fstab file activate the changes.

35 System modules (Cont’d) Running Processes Webmin's process manager resembles a browser-based version of the famous top utility allows to execute an arbitrary command screen is obtained by clicking the “Running Processes” icon The display is sorted either by process ID or by selecting the link of username, memory usage, and CPU time consumed

36 System modules (Cont’d) Running Processes Can be used after filling in the searching criteria by clicking the corresponding search button CriteriaDescription Owned byEnter a user name MatchingEnter a string Usage % CPUEnter between 0 and 100 Using filesystemSelect a filesystem Using fileEnter a filename

37 System modules (Cont’d) Running Processes Can be used to change process priority click a PID from either the main listing or a search screen select a new priority (called a nice level) then click the “Change” button

38 System modules (Cont’d) Running Processes Common process signals with webmin SignalDescription INTSends a keyboard interrupt (Ctrl+C) QUITTerminates the process. ABRTTerminates the process and creates a memory dump KILLTerminates the process TERMTerminates the process STOPStops the process, but does not kill it CONTResumes a stopped process