1. 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 Head of the DepartmentMr.Chethan K.C.,B.E,M.Tech Dr. K.C Ravishankar B.E., M.Tech., Ph.d Professor & Head,Dept.of Asst.professor CS&E, GEC,Hassan
2. Linux Administration
3. Contents1. Introduction2. Admin Tasks3. Installation of Linux4. Admin Login5. User and Group management6. Security7. Backup & Restore8. Packages9. Conclusion
4. Introduction• Linux is based on Unix• Administration involves the management of entire system• From maintaining user accounts to performing backups
5. 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..
6. Installation of LinuxSeveral 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.
7. Admin LoginTwo ways- • Login directly as root • Using su command
8. User management• Done using either CLI or GUI.Using CLI: 3 commands are used-useradd- Creates or adds a newuserusermod- Modifies the useraccount like username, passwordetc.,(options –l, -p, -d,-g,-u )userdel- Deletes the user. –roption is used to delete homedirectory
9. User management using GUIGo to the System => Administration=> Users & Groups.Click on Add User and the do thefollowing instructionsAdd the user name, full name of theuser, passwordClick on OK and the user gets addedto the system.
10. Group management• Similar kind of users are added to a particular group.• 3 commands are used-groupadd- adds or creates agroupgroupmod- modifies agroup(options –g, -n, -p)groupdel- deletes a particulargroup
11. Networking• Basic tools used for networking are ping, ftp, telnet and ssh.• 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.
12. Communicating with Users• The admin should communicate with the users to intimate about the changes.• Commands used-wall- addresses all userssimultaneously who arecurrently logged in. Syntax: wall msgwrite-addresses a single userSyntax: write username [tty] msg
13. Managing System Services• System services can be managed using either service command or GUI.• Using service command:Start a service-service service_name startStop a service-service service_name stopRestart a serviceservice service_name restart
14. Managing Services Using GUIGo to the System =>Administration => Services.This opens a ServiceConfiguaration window.Click on the required Service tostart, stop or restart it.Give the admin passwordwhenever prompted and click ok.
15. 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
16. SELinux• 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 ofenforcing.disabled - SELinux is fully disabled
17. SELinux Configuration• 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
18. Backup & Restore• 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
19. Adding & Removing Packages• 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.
20. 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
21. Using YUM(Yellowdog Updater, Modified)• 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
22. Conclusion Conclusion• Discussed only few essential linux administration tools.• Full administration requires an in-depth knowledge of different components of system.