sysintro

Slide 1:Computer System Administration Instructor: J.T. Yang (jjyang@csie.nctu.edu.tw)

Slide 2:Introduction to System Administration Job of system administration accounting, monitoring resource management & planning software & hardware installation programming, negotiation, consulting super user su, su root -c CMD, and sudo communication with users write, wall, /etc/motd, pre-login message in /etc/issue 1. su philosophy.... 2.1. su philosophy.... 2.

Slide 3:Introduction to System Administration (c.1) system adminstration tools AIX(SMIT, VSM) IRIX(Cadmin facility) HP/UX(SAM) Solaris(admintool) Linux xadmin in Linux-FT distribuiton control-panel in Yggdrasil dist. Caldera Network Desktop. (RedHat dist.) 3rd-party commercial product

Slide 4:UNIX Concept-- Files ownership and modes owner, group, other read, write, execute setuid, setgid, sticky, file locking chown, chgrp, chmod Advance problems umask setgid attribute on directories sticky attribute on directories setuid attribute on files setgid attribute on files

Slide 5:UNIX Concept -- Files (c.1) Type and attributes of files inode -- store attribute and location of all files regular file, directory, links, socket, named pipe, char/block device (ls -F) * / @ = | (ls -l) - d l s p c b ‘file’ commands tell file formats in files, such as OBJ, EXE, text file, nroff, ... /etc/magic

Slide 6:UNIX Concept-- Process interactive process job control of shells&, ^Z, jobs, %n, fg, %?str, bg, kill, ~^Z, ~~^Z, ~~~^Z, ... batch process daemon process Process attributes PID, PPID, Nice number RUID, EUID, RGID, EGID setuid( getuid() )

Slide 7:UNIX Concept-- Processes (c.1) Life cycle of process fork, exec, vfork. ‘ps’ commands ps -ux, ps -aux, ps -auxwwe ps -elf kill commands SIGTERM, SIGHUP SIGUSR1, SIGUSR2 renice commands

Slide 8:UNIX Concept -- Devices (c.1) block and character devices major, minor disk naming convention p55. Fig 2-5 common device names P55, Table 2-6 floopy, tape driver, cdrom tty, /dev/null, /dev/zero /dev/MAKEDEV find device information sysinfo, dmesg, ioscan(hp), lscfg(AIX), ...

Slide 9:UNIX FAQ for users deleting a special file? refer to UNIX FAQ at course home page

Slide 10:Essential commands man, man -k sort, uniq, wc grep, awk, egrep regular expression find type, name, perm, mtime, print ok, exec head, tail, sed xargs, tar, zip, gzip,GNU bin utilities shell programming sh, csh, perl

Slide 11:Chapter. 2Startup and Shutdown UNIX boot process boot process for PC boot single user password protection boot multiuser System V Run Level (p.90, p111) 0: shutdown, S: single user 2,3 : multiuser 6: rebooting boot message

Slide 12:Startup and Shutdown (c.1) Initialization process and startup scripts preliminaries preparing filesystem fsck, mount /, mount local disk, saving crash dump, start paging, security related activity, check quota starting server and local subsystem networking house keeping allow users to login

Slide 13:Startup and Shutdown (c.2) Initialization files SunOS 4.1.x /etc/rc.boot /etc/rc.single /etc/rc /etc/rc.local System V /etc/rcN for V3, /sbin/rcN for V4 /etc/init.d and /etc/rcN.d Startup: level 0 --> level 2 Shutdown: level 6

Slide 14:Startup and Shutdown (c.3) Shutdown and reboot (BSD)sync; sync; sync; shutdown -h -t 5 now “shutdown now....” (SysV) shutdown -g n -I level -y 0, 1, S, 5, 6 (power off, admin, single user, monitor, reboot to initdefault) reboot, halt Abort shutdown, Fake shutdown Power failure shutdown

Slide 15:Startup and Shutdown (c.4) Trouble shoot for system crash Don’t Panic... run out of system resource hardware failure/incompatible filesystem failure system integration error