1 / 15

Introduction to Unix Administration

Introduction to Unix Administration. Objectives to identify the basic concepts of Unix administration Contents history of Unix unix vendors and standards working as root system administration shells Practicals evaluating an administration shell Summary. Unix. Unix - PDP/7.

jeslyn
Download Presentation

Introduction to Unix Administration

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Introduction to Unix Administration • Objectives • to identify the basic concepts of Unix administration • Contents • history of Unix • unix vendors and standards • working as root • system administration shells • Practicals • evaluating an administration shell • Summary Unix

  2. Unix - PDP/7 Unix 1st edition - PDP/11 BSD Unix System III BSD 4.1 XENIX Amdahl UTS Unix System V BSD 4.2 SCO Unix BSD 4.3 AIX Unix System V.3 SunOS 4 AIX 3.1 Solaris 1.0 UnixWare 1.0 Unix SVR4.2 Solaris 2.0 AIX 4.1 UnixWare 2.0 Unix - Genealogy Systems Date 1969 1972 1975 1978 1981 1983 1985 1987 1989 1991 1993 1995 1 25 500 100000 2800000 5000000 Unix 5/6th edition - C Unix 7th edition - non PDP SunOS Unix System V.4 - SVR4

  3. Major Unix Versions • AT&T System V • currently release 4.2 (SVR4.2) • most widely implemented version of Unix • Berkeley Software Distribution (BSD) • pure BSD systems usually found as free Unix on PCs • OSF/1 derived from BSD with SVR4 additions HP HP/UX SVR4 + OSF/1 ICL DRX SVR4 SNI/Pyramid DC/OSx SVR4 Silicon Graphics Inc IRIX SVR4 SCO UnixWare SVR4 Sun Microsystems Solaris 2 SVR4 SCO SCO Unix SVR3.2 Sequent Dynix/PTX SVR3.2 + security Sun Microsystems SunOS 4 BSD DEC Digital Unix OSF/1 + SVR4 IBM AIX OSF/1 + SVR4

  4. Unix Standards • Unix has been standardised • SVR4, OSF/1, POSIX, spec1170 • standards concentrate on kernel functionality and API • administration not covered by standards • Administration is similar for all Unix systems • command names can vary from one variant to another • command options can vary • some systems provide better support for administrators than others • Unix administration is developing standards • Distributed Computing Environment (DCE) • Domain Name Services (DNS) • Common Desktop Environment (CDE)

  5. Scope of this Course • To cover basic administrative functions • describe underlying concepts and utilities • Features described in a vendor independent manner • concentrate on SVR4 • reference to other systems where appropriate • Cover common areas of administration in detail • users, processes, files & backups • networking, terminals & printers • Introduce less common administration • installing the system and software • accounting & performance monitoring • Useful commands are briefly described • use the on-line manual pages for full information

  6. Discussion - Administration Roles • What are the typical jobs performed by a Unix System Administrator in the following categories? Operations Administration Technical Support ? ? ?

  7. General Responsibilities • Identify your role and responsibilities • can you delegate some of your work? • Find out about your system • when was it purchased • do you have hardware maintenance, if not why not? • do you have OS maintenance, if not why not? • What hardware does your system have? • What software is installed? • is all the software necessary • Who uses your system?

  8. System Logbook • Keep a logbook for each system • Record activities such as • system crashes • maintenance, • hardware problems • system upgrades • software installations • Keep as paper copy, not an on-line copy

  9. Working As Root • Nearly all Unix administration must be done as user root • this superuser account (user id 0) has unrestricted access to the system • Administration should be done by one person at a time • check that no one else is logged in as root • if someone else is working as root, find out what they are doing • In a secure room, keep the console logged in as root • useful for getting out of trouble if system starts to hang • do all administration from the console • disable root logins on other terminal lines for security WARNING root can irrevocably damage the system take care when working as root

  10. The su Command • The set user (su) command changes to another user • runs a new shell for the new user • exit from the new shell to resume original user's shell • su changes your effective user id (and group id) • most commands use effective uid/gid for access control • real uid/gid not changed • be aware that some commands always use real uid/gid • Root can use su without providing a password • other users must supply a password $ su - root password: work as root, with root's environment

  11. Running Commands with su • su can be used to run a command as another user • Use the -c option to specify a "command string" • useful for including in shell scripts • su defaults are in /root/.bash_profile • it it usual for root to have a separate su path • su attempts are logged in /var/log/messages • Permission file: /etc/sudoers tell who is allowed to su • Permission file is edited with command visudo # /bin/su - printer -c “cleanup” run the printer cleanup script # more /root/.bash_profile

  12. Exercise - Using su • What do the following commands do and which ones require a password? $ su # su - henry $ su - # su - root -c poweroff # exit $ su root -c "rm /tmp/.lock321"

  13. Traditional Administration • Traditionally, Unix administration requires a good knowledge of the Unix operating system • Administrators work directly with configuration files and special programs • Administrators develop or borrow extra programs and scripts to support standard utilities • Difficult for novice administrators even to get started...

  14. Administration Shells • System manufacturers often provide menu driven administration interfaces • some are better than others • some only work under X-Windows • Admin shells are not as comprehensive as one would like • Unix administrators still need to know about underlying commands • smit on AIX is awarded to be the most friendly and comprehensive front end to administration Linux WebMin http SuSE YaST tty & X AIX SMIT tty & X Digital Unix setup tty HP/UX SAM X IRIX Cadmin X SCO Unix sysadmsh tty Solaris 2 admintool X SVR4 sysadm tty

  15. Summary • Unix administration is similar but not identical for all systems • Unix administrators tend to learn a lot about how Unix works • Nearly all administration is undertaken as the superuser (root) • Administration shells such as sysadm or SMIT can simplify Unix for novice administrators • Use the su command to run a shell as another user • When you know one Unix system you can easly learn all other dialects. • SuSE uses yast and yast2 for most common admin work.

More Related