Lab 8 Overview

1. Lab 8 Overview Apache Web Server

2. Package Management Systems Groups Scripts Linux Tricks

3. Linux Tricks Packages

4. Packages • Used to “package” software for Linux distributions • Vary by distribution type • Debian • APT (Advanced Package Management Tool) • .deb files • Red Hat • RPM (RPM Package Management) • Originally Red Hat Package Management) • .rpm files

5. Package Management System • Aids in the installation, configuring, upgrading and removal of software packages • Several styles • Debian • dpkg – base tool • apt – cli interface • synaptic – gui interface • Red Hat • yum – base tool • Has a cli • PackageKit – gui interface • Plenty of other systems • Mandriva • MPM under dev. • Drakrpm • Slackware • pkgtool

6. PMS vs. Installer

7. Linux Tricks Userids, groups and permissions

8. Groups and Permissions • Learn the use of groups in file permissions

9. Overview • Create a text file while logged on with your user ID • Small file 3-5 lines • Change the file’s group • E.g. group01 • Change the file’s permissions to 640

10. Overview • Try to edit and view the file when logged on with a different ID • e.g. user01 • Note: use01 must belong to group01 • Try to edit and view the file when logged on with a third ID • .e.g. user02 • Note: user02 must belong to another group

11. Overview • Try changing the file when logged on as root • Optional: • Try deleting the text file as user02 • Try deleting the text file as user01 • Try deleting the text file as root • Remember: • Document text with text, not screen captures • Mainly things done via the CLI

12. Linux Tricks Scripts

13. Scripts • Small programs to help the maintaining and configuring of an operating system • Executed by the shell • Syntax dependent on shell • Typical use: • Create a bunch of new users • Configure a services • De facto extension: • .sh

14. Change terminal color Assume a file named changecolor: #! /bin/bash# script to turn the screen bluesetterm -background blueecho It is a blue day Line 1: specifies which shell should be used to interpret the commands in the script.Line 2: is a comment (has no effect when the script is executed).Line 3: sets the background colour.Line 4: displays a message. To execute if the PWD has this file: ./changecolor If in another directory use the complete name: /home/mydir/utils/changecolor

15. Simple Menu Script These can be as complex as needed with conditional and loop controls (among many other things) #!/bin/bash OPTIONS="Hello Quit" select opt in $OPTIONS; do if [ "$opt" = "Quit" ]; then echo done exit elif [ "$opt" = "Hello" ]; then echo Hello World else clear echo bad option fi done

16. Running Scripts Basics • Make sure the first line is a directive of which shell to use (if needed) • Starts with a shebang: #! • For our Debians it is the bash shell • /bin/bash • Make sure it is executable • rwxr-xr–- • User can run, edit and view • Group can run and view • World can view • chmod 754 script.sh • If the shell is in a directory defined in the PATH • echo $PATH • Will show the directories • type: filename • If it is not in PATH but it is in the PWD • type: ./filename • If not in PATH and not in the PWD • type full filename starting with the root: /home/ajkombol/Desktop/script.sh

17. Script one: netconfig.sh Desired action: stop the NIC, open the interfaces file to edit, restart the NIC, add two nameservers to the resolve.conf file The script: #!/bin/bash NETCONFIGFILE=/etc/network/interfaces RESOLVECONF=/etc/resolv.conf ifdown $1 vi $NETCONFIGFILE #vi $RESOLVECONF ifup $1 echo 'nameserver 172.16.1.245' >> $RESOLVECONF echo 'nameserver 172.16.1.219' >> $RESOLVECONF To execute the script: myprompt#./netconfig.sh eth0

18. Quick script intro • Parameters passed to a script are denoted by $1, $2, $3, … • $1 is the first parameter, $2 is the second, etc. • $# is the number of parameters passed • Conditionals are done by an if…elif…else…fi structure • The if and elif are followed by command that evaluates to true or false • The elifand else are optional • elifcan be repeated • Only one else may be used, if needed • The if is closed with thefi statement • To stop in the middle of a script use exit n • n = 0 is a normal exit • n = 1 is an error exit • If a value needs to be checked the test command is used • Numbers use conditionals • e.g. –gt, -lt, and –eq • greater than, less than, equal • E.g. test 1 –gt 2 • Strings use operators • e.g. = or != • equal and not equal • test $1 = "opt1" • There are other comparisons that can be done, check the internet • Variables are case sensitive • Are UPPER case by convention for environment variables

19. Script two: go Disired action: stop the NIC, check option and copy the proper template to interfaces, and finally restart the NIC #!/bin/bash IFILE=/etc/network/interfaces ifdown eth0 if test $1 = "static" ; then cp $IFILE.static $IFILE echo "Static interfaces loaded!" elif test $1 = "dhcp" ; then cp $IFILE.dhcp $IFILE echo "DHCP interfaces loaded!" else echo "Parameter must be static or dhcp" fi ifup eth0 To execute the script: myprompt#./go static … myprompt#./go dhcp

20. Today's labs scripts summary • Changing network configuration • Script one – editing the interfaces file • stop NIC • edit interfaces • add some additional routing information • start NIC • Script two – alternating interfaces templates • Make two interfaces templates • stop NIC • Copy the desired template • start NIC • You may wish to keep these scripts • Use netconfig.sh to edit the interfaces file • After making appropriate changes • Use go or go2 to switch between • DHCP addresses • Static addresses

21. Reminder • ALWAYS make a backup copy of a configuration file BEFORE editing it • Will allow the file to be restored • If you mess it up • If something else messes it up • Examples: • cp interfaces interfaces.backup • cp apache2.conf apache2.conf.orig

22. Main Lab Apache

23. Apache Web Server • Main Goals • Install Apache • Configure basic system • Configure restrictions • Side goals • Installing packages on a Debian System • Reinforce VM environment • Reinforce use of vi editor

24. Apache Web Server Overview • Install Apache on your Debian VM • apt-get • Backup: Synaptic Package Manager • No credit for Synaptic install • Check if installation worked • Create new directories • “Install” the web application • Configure Apache to “find” the new “application” • Copy Web page files into proper directories • Hint: assume the Web application is being moved from a different Web server to this machine • Configure Apache for restrictions • Allow directory access • Deny directory access • Browse the application from another machine

25. Misc. Notes • Debian required for the Apache Server • CentOS recommended for the browsing client • Can be any OS with a browser • Use ifconfig to identify your IP address • Web files (.htm and pics) available on hades.lab • Use browser to locate • class/itis2110/apache • e.g. master.hades.lab/classes/itis2110/apachelab • (172.16.1.245) • In /public directory • Also available • ON website • on thumbdrive • You will need to figure out on your own where the images go to be properly displayed • All web pages except home have an image • A subdirectory is involved!

26. IMPORTANT!!!! • This Debian VM must be working and saved! • Will be used as the basis for the DNS Lab!

27. Apache Overview • “Open source” web server • Default browser “root” directory • NOT the same as the host’s root directory! • To access the web server: • Use the IP address or host name • Port 80 • Bonus: • At end of lab add port to browse on port 8080 • Document results

28. Last minute notes: • Check the links to test1.html and test2.html • They should go to the ITIS2110 directory • If you get an old copy they may point to an ITIS3100 directory • Fix accordingly! • Change reference in the html (best) • -- or -- • Change the directory name • Watch the IP addresses of your VM • DHCP OK this lab • Need to look up address for browsing • If address was assigned • Be sure does not conflict with another machine • Can use machine ID as subnet or host id

29. Apache Lab • Lab 20 pts