linux administration

VISVESVARAYA TECHNOLOGICAL UNIVERSITY BELGAUM

Technical Seminar On “Linux Administration”

By YOGESH K S 4GH08CS058 Under the guidance of Mr.Annaiah.,B.E.,M.Tech

Asst.professorSeminar co-ordinator

Mr.Chethan K.C.,B.E,M.Tech

Asst.professor

Head of the DepartmentDr. K.C Ravishankar B.E., M.Tech., Ph.d

Professor & Head,Dept.of CS&E, GEC,Hassan

Linux Administration

Contents

1. Introduction2. Admin Tasks3. Installation of Linux 4. Admin Login5. User and Group management6. Security7. Backup & Restore8. Packages9. Conclusion

Introduction

• Linux is based on Unix

• Administration involves the management of entire system

• From maintaining user accounts to performing backups

Admin Roles & Tasks

• Install and Upgrade systems• User management• Group management• Security• Networking• Backup and Restore• Communicate with the users• Managing System Services• Adding or Removing application packagesand many more..

Installation of Linux

Several methods are available some of them are:

• FTP: One of the earliest method used for performing network installations

• HTTP: Installation is served from a web server.

• NFS: Distribution tree is shared/exported on an NFS server.

• From the Optical or removable media.

Two ways-• Login directly as root • Using su command

Admin Login

User management

• Done using either CLI or GUI.

Using CLI: 3 commands are used-useradd- Creates or adds a new userusermod- Modifies the user account like username, password etc., (options –l, -p, -d,-g,-u )userdel- Deletes the user. –r option is used to delete home directory

Go to the System => Administration => Users & Groups.

Click on Add User and the do the following instructions

Add the user name, full name of the user, password

Click on OK and the user gets added to the system.

User management using GUI

Group management

• 3 commands are used-groupadd- adds or creates a groupgroupmod- modifies a group(options –g, -n, -p)groupdel- deletes a particular group

• Similar kind of users are added to a particular group.

• Basic tools used for networking are ping, ftp, telnet and ssh.

Networking

• ping is used in checking the network.

• ftp is used to transfer files between hosts.

• telnet is used for remote login.

• ssh is also used for remote login and is secure.

• The admin should communicate with the users to intimate about the changes.

• Commands used-wall- addresses all users simultaneously who are currently logged in. Syntax: wall msg

write-addresses a single userSyntax: write username [tty] msg

Communicating with Users

• Using service command:Start a service-service service_name startStop a service-service service_name stopRestart a serviceservice service_name restart

• System services can be managed using either service command or GUI.

Managing System Services

Managing Services Using GUI

Go to the System => Administration => Services.

This opens a Service Configuaration window.

Click on the required Service to start, stop or restart it.

Give the admin password whenever prompted and click ok.

Security

• Linux is more secure and it is enhanced with its Firewall and SELinux.

• Firewall: Enable Firewall Using GUI (System-> Administration->Firewall) to activate the firewall

• Allow standard services and any specific port based application

• All other services and ports are blocked

• Malicious or broken software can have root-level access to the entire system by running as a root process.

• SELinux (Security Enhanced Linux) provides enhanced security.

• SELinux can take one of these three valuesenforcing - SELinux security policy is enforced.permissive - SELinux prints warnings instead of enforcing.disabled - SELinux is fully disabled

SELinux

• Use GUI (Applications ->System Settings-> Security Level) to activate SELinux

• Enable/Disable SELinux• Allow standard features

in various services (http,nis,nfs,dns etc.)

• All other services and features are blocked

SELinux Configuration

• Backup the user area or configuration file• Use tar to take backup on a different disk or tape• Backup can be scheduled using cron• Backup: tar –zcvf <dev filename> <Directory Tree to

be backedup>• Restore: tar –zxvf <dev filename> <file to be

recovered>• Backup should be occasionally checked by restoring it• Backup Policy: Full Backup every weekly/fortnightly

and incremental backup every day

Backup & Restore

• Can be done using source code of the package, binary rpms or yum utility.

• Using source code-• This is hard way to install a package.• Usual steps-Download the required tar compressed file and extract it.Run ./configure and make for compiling.Run make install.• May run into problems because of shared libraries or

compilation.

Adding & Removing Packages

Using RPM(Redhat Package Manager)

• Be aware of Architecture and type of kernel.• Syntax: rpm [options] file.rpm(-i=install, -U= upgrade,

-e= erase)• To install a package: rpm –i pkg.rpm • To remove a package: rpm –e pkg

• Easiest way to install a package.• No need to worry about architecture and kernel.• Resolves dependencies automatically.• Syntax to install: yum install package-name• To uninstall any package: yum remove package-

name

Using YUM(Yellowdog Updater, Modified)

Conclusion

• Discussed only few essential linux administration tools.

• Full administration requires an in-depth knowledge of different components of system.

Conclusion

Any Qs?

ThanQ You