OPS235 Lab 5 - CentOS6
Contents
- 1 Archiving Files, Compiling Software Packages from Source, Managing Services
- 1.1 Overview
- 1.2 Objectives
- 1.3 Required Materials (Bring to All Labs)
- 1.4 Prerequisites
- 1.5 Linux Command Online Reference
- 1.6 Resources on the web
- 1.7 Archiving Files / Compiling Software from Source Code
- 1.8 Managing Run-Levels and System Services
- 1.9 Completing the Lab
- 1.10 Preparing for Quizzes
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 on your computer server. In addition, you will learn 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
- To create and use archive files (tar and tar.gz)
- Compiling software packages from source code
- Install an application from software development repositories using the bit utility
- Customising file-system start-up
Required Materials (Bring to All Labs)
- CentOS 6.5 x86_64 Live DVD
- CentOS 6.5 x86_64 Installation DVD1
- SATA Hard Disk (in removable disk tray)
- USB Memory Stick
- Lab Logbook
Prerequisites
- Completion and Instructor "Sign-off" of Lab 4: OPS235 Lab 4 - CentOS6
Linux Command Online Reference
Each Link below displays online manpages for each command (via http://linuxmanpages.com):
Archiving Utilities: | Service Management Utilities: | |
|
Resources on the web
Additional links to tutorials and HOWTOs:
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.
Investigation 1: How do you create an archive file?
- Boot up your centos3 VM.
- Change your working directory to
/usr/share/doc/sudo*
- Use the tar (tape archiver) command to create an archive file named
/tmp/archive1.tar
tar cvf /tmp/archive1.tar .
- What do the options c, v, and f mean?
- Record the archive file size.
- Compress the file using
gzip
:gzip /tmp/archive1.tar
- Record the archive file size after compression.
- Make sure you're still in
/usr/share/doc/sudo*
and then create a compressed archive:tar cvzf /tmp/archive2.tgz .
- What does the
z
option do? - 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?
- Create the directory
/tmp/extract1
- Change to the
/tmp/extract1
directory. - Move the file archive1.tar.gz to your current directory.
- Unzip the first archive you created:
gunzip archive1.tar.gz
- Extract the files from the first archive:
tar xvf archive1.tar
- Are all the files there?
- Compare
/tmp/extract1/README
and/usr/share/doc/sudo*/README
. Are they exactly the same? Why? - Create the directory
/tmp/extract2
- Move the file archive2.tgz to the
/tmp/extract2
directory. - Extract the files from the second archive:
tar xvzf /tmp/extract2/archive2.tgz
- Note that this time a separate
gunzip
command was not needed. Why? - Repeat the previous command, leaving out the option "z". Does it work? Why?
- 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...
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.
- Issue the following command to install a basic set of development tools and libraries:
yum groupinstall "Development Tools" "Development Libraries"
- Go to the directory
/tmp
- 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. - Extract the files. Change to the newly-extracted directory (
/tmp/nled-2.52
) - 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) - Check to see if there is a file named
Makefile
ormakefile
. If so, type the command:make
- Did the command work? Why? Use the
yum/code> command to install the package gcc. What do you think the package gcc does?</li> </ul>
command. Where you successful? What does- Reissue the <code>make
make
do? - Some software distributed as source code can automatically install itself. Try this command:
make install
- Most but not all source code archives include the capability of installing themselves this way.
- If the command
make install
does not work (how can you tell?), copy thenled
program manually:cp nled /usr/local/bin
- Test
nled
to make sure it works. - Issue the following Linux command:
runlevel
- Note the difference in output between centos2 and centos3.
- You can use the init command to change the current runlevel. See a list of runlevels here. Change the current runlevel in centos2 to 3. What happened? What happens after your reboot?
- Change the default runlevel on centos2 to 3. What happens now after you reboot?
- Issue the following Linux command:
startx
- What happens?
- Log-off your graphical system. You should return to your shell prompt.
- Change the default runlevel for centos2 back to 5 and reboot to make sure it works.
- Issue the following Linux command:
service --status-all
- Note the services that are currently running.
- Use the
service
command to stop the service named iptables - Issue the
service
command to verify that this service has stopped. - If you reboot now - the iptables service will be turned back on. We don't want it on though, it causes students headaches. To turn it off permanently we need to use the chkconfig command:
chkconfig iptables off
- Reboot and confirm that it's no longer running.
- Compressed files:
/tmp/archive1.tar.gz
and/tmp/archive2.tgz
nled
application is installed- Lab5 notes how to use service/chkconfig commands
- VMs backed-up
- What is the advantage of disabling services such as bluetooth?
- What is the difference between a .tgz file and a .tar.gz file? What do these stand for?
- What is the purpose of a repository?
- What is source code?
- How do you build software from source code?
- Which is preferred: installing from an RPM file, or installing from source code? Why?
- How do you use
service/init/chkconfig
to:- show/set current 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?
</ol>
Answer the Investigation 3 observations / questions in your lab log book.
Managing Run-Levels and System Services
Investigation 4: How do we Manage Runlevels?
The runlevel command is now deprecated in Fedora, and will likely be deprecated in RHEL/CentOS at some point as well, but for now this is what the industry is using.
Answer the Investigation 4 observations / questions in your lab log book.
Investigation 5: How do we Manage System Services?
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.}}
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:
Preparing for Quizzes