OPS235 Lab 5 - Fedora17

Archiving Files, Compiling Software Packages from Source, Managing Services

Overview

• In this lab, you are going to help conserve disk space by learning how to compress and decompress files that are stored your computer server. In addition, you will alternative methods of how to install programs (decompressing zipped tarball archives and then compiling source code).

• In addition, you will learn about how certain processes (services) work, and how the system administrator can manage these services (i.e. turn "on" and "off").

Objectives

1. To create and use archive files (tar and tar.gz)
2. Compiling software packages from source code
3. Install an application from software development repositories using the bit utility
4. Customising file-system start-up

Required Materials (Bring to All Labs)

• Fedora 16 LIVE CD - You can burn this onto a CD-R in the Open Lab
• Fedora 16 x_64 Installation DVD - You can burn this onto a DVD-R in the Open Lab (or burn image onto a DVD+R if you are using the Freedom Toaster).
• SATA Hard Disk (in removable disk tray)
• USB Memory Stick (minimum 64M)
• Lab Logbook (Lab5 Reference Sheet) (to make notes and observations).

Prerequisites

• Completion and Instructor "Sign-off" of Lab 4: OPS235 Lab 4

Linux Command Online Reference

Each Link below displays online manpages for each command (via http://linuxmanpages.com):

Archiving Utilities:	Service Management Utilities:
tar gzip gunzipzip make	systemctl

Resources on the web

Additional links to tutorials and HOWTOs:

• archiving with tar, gzip, gunzip
• Compiling Software from Source Code
• init vs systemd

Archiving Files / Compiling Software from Source Code

Archive files are often used to contain source code for software; in this lab you will also be compiling software from a source code archive.

Do not Shut-Down VMs Until Instructed
You will be running all 3 VMs eventually when performing this tutorial, Leave all VMs running until you are instructed to shut them down at the end of this lab.

Investigation 1: How do you create an archive file?

Use fedora3
Perform these steps in the fedora3 virtual machine.

1. Boot up your fedora3 VM.
2. Change your working directory to /usr/share/doc/sudo*
3. Use the tar (tape archiver) command to create an archive file named /tmp/archive1.tar
   • tar cvf /tmp/archive1.tar .

Warning!
Don't miss the . at the end of the tar commands below! It specifies what should go into the archive: the contents of the current directory.

4. What do the options c, v, and f mean?
5. Record the archive file size.
6. Compress the file using gzip:
   • gzip /tmp/archive1.tar
7. Record the archive file size after compression.
8. Make sure you're still in /usr/share/doc/sudo* and then create a compressed archive:
   • tar cvzf /tmp/archive2.tgz .
9. What does the z option do?
10. Compare the sizes of /tmp/archive1.tar.gz and /tmp/archive2.tgz. Why are they so close in size?

Answer the Investigation 1 observations / questions in your lab log book.

Investigation 2: How do you restore files from an archive?

Remain in your fedora3 VM
Perform these steps in the fedora3 virtual machine.

1. Create the directory /tmp/extract1
2. Change to the /tmp/extract1 directory.
3. Move the file archive1.tar.gz to your current directory.
4. Unzip the first archive you created:
   • gunzip archive1.tar.gz
5. Extract the files from the first archive:
   • tar xvf archive1.tar
6. Are all the files there?
7. Compare /tmp/extract1/README and /usr/share/doc/sudo*/README. Are they exactly the same? Why?
8. Create the directory /tmp/extract2
9. Move the file archive2.tgz to the /tmp/extract2 directory.
10. Extract the files from the second archive:
    • tar xvzf /tmp/extract2/archive2.tgz
11. Note that this time a separate gunzip command was not needed. Why?
12. Repeat the previous command, leaving out the option "z". Does it work? Why?
13. Compare the README file in this directory with the original file. Are they exactly the same?

Answer the Investigation 2 observations / questions in your lab log book.

Investigation 3: How do you build software from source code?

Now that you know how to create and decompress "zipped tarball archives", we will demonstrate how to install applications from websites containing these types of archives. Although this method is not as "user-friendly" as using the yum or rpm command, this method is useful if the application is NOT contained in regular software repositories...

Use fedora2
Perform these steps in the fedora2 virtual machine.

In order to build software from source code, you must have the appropriate software development tools (such as make and gcc) and libraries (such as GTK) installed. The required tools will vary depending on the computer languages used in the software being built.

1. Boot up your fedora2 VM.
2. Issue the following command to install a basic set of development tools and libraries:
   yum groupinstall "Development Tools" "Development Libraries".

Installing Development Libraries
In the future, remember the above procedure whenever installing software from source. Sometimes, you need to install additional tools or libraries in order to compile a particular software package

3. Go to the directory /tmp
4. Use the wget command to download the "tar ball" that contains the source code for the NLED text editor. wget is a command-line tool to download files from the web using the http or ftp protocols.
   • wget http://cdot.senecac.on.ca/software/nled/nled_2_52_src.tgz
5. Extract the files. Change to the newly-extracted directory (/tmp/nled-2.52)
6. Check to see if there is a file named configure. If so, run it; if not, skip this step. (Most but not all source code archives contain this file)
7. Check to see if there is a file named Makefile or makefile. If so, type the command:
   • make
8. What does make do?
9. Some software distributed as source code can automatically install itself. Try this command:
   • make install
10. Most but not all source code archives include the capability of installing themselves this way.
11. If the command make install does not work (how can you tell?), copy the nled program manually:
    • cp nled /usr/local/bin
12. Test nled to make sure it works.

Answer the Investigation 3 observations / questions in your lab log book.

Managing Run-Levels and System Services

Investigation 4: How do we Manage Runlevels?

Use fedora2
Perform these steps in the fedora2 virtual machine.

Runlevel is a Unix/Linux term relating to the operating system's mode of operation. For example, if the operating system operates in text-based or graphical mode, reboot, shutdown, etc.

We will be learning to switch to different runlevels in your fedora2 virtual machine.

1. Switch to your fedora2 VM.
2. Issue the following Linux command to determine your runlevel:
   • runlevel
     The number 5 indicates that your fedora2 VM is currently in "runlevel 5" or "graphical mode with networking".

The runlevel command is now depreciated
Although you can still use the runlevel command, it is considered obsolete (deprecated), and has been replaced by systemctl.
The newer system called systemd is a newer method to help simplify controlling both runlevels (referred to as "targets" and system services (referred to as "services").
Refer to the tutorial init vs systemd for systemctl command usages and reference.

3. Issue the following Linux command:
   • systemctl list-units --type=target
4. Note the target labelled graphical. What does this indicate about your fedora2 VM?
5. Issue the following commands to switch the default mode (also known as target or runlevel):
   • rm /etc/systemd/system/default.target
   • ln -sf /lib/systemd/system/multiuser.target /etc/systemd/system/default.target
6. Restart your fedora2 VM. What happens?
7. Log into your regular user account.
8. Issue the following Linux command:
   • startx
9. What happens?
10. Log-off your graphical system. You should return to your shell prompt.
11. Issue the following commands:
    • rm /etc/systemd/system/default.target
    • ln -sf /lib/systemd/system/graphical.target /etc/systemd/system/default.target
12. Reboot your fedora2 VM. What Happens?

Answer the Investigation 4 observations / questions in your lab log book.

Investigation 5: How do we Manage System Services?

Remain in your fedora2 VM
Perform these steps in the fedora2 virtual machine.

We have seen that maintaining unneeded packages can be a security risk due to the unnecessary increase in the complexity of your system. Similarly, it is also unnecessarily hazardous, and even more so, to leave unneeded services running. In this investigation, we will learn how to control services, and turn off those services that we think are not necessary to help reduce security risks.}}

1. Issue the following Linux command:
   • chkconfig --list
2. Note the services that are running.

'chkconfig' command is now deprecated
The chkconfig command has now been replaced by the systemctl command to manage system services.

3. Issue the following Linux command:
   • systemctl list-units --type=service
4. Note the services that are currently running. Are there more services with this command as opposed to issuing the chkconfig command? How to you issue the systemctl command to list the current run-level?
5. Refer to the tutorial (init vs systemd ) to learn how to use the systemctl command to stop the service name called udev.service
6. Issue the systemctl command to verify that this service has stopped.
7. Issue the systemctl command to start the udev service, and verify that this service is running.

Answer the Investigation 5 observations / questions in your lab log book.

Completing the Lab

Arrange evidence for each of these items on your screen, then ask your instructor to check each item:

1. Compressed files: /tmp/archive1.tar.gz and /tmp/archive2.tgz
2. nled application is installed
3. Lab5 notes how to use systemctl commands
4. VMs backed-up

Preparing for Quizzes

1. What is the advantage of disabling services such as bluetooth?
2. What is the difference between a .tgz file and a .tar.gz file? What do these stand for?
3. What is the purpose of a repository?
4. What is source code?
5. How do you build software from source code?
6. Which is preferred: installing from an RPM file, or installing from source code? Why?
7. How do you use systemctl to:
   • list runlevel
   • list services
   • stop a service
   • start a service
   • Why is it important to learn how to manage services?
   • Why is it important to stop certain services?

Backup your work
Backup your disk images for fedora2 and fedora3 Virtual Machines.