Changes

=[[Category:OPS235 ]] {{Admon/caution|Draft Lab 5 - Loopback Filesystems|This lab has NOT been released for regular distribution. When the lab is ready to be released, Archivesthis caution banner will disappear.}} =Archiving Files, Compiling Software Packages from Source, Managing Services=

#Compiling software packages from source code#Customizing Install an application from software development repositories using the bit utility#Customising file-system startupstart-up 

==PrerequisitesLinux Command Online Reference==Each Link below displays online manpages for each command (via [http://linuxmanpages.com/ http://linuxmanpages.com]):

{|width="100%" cellpadding="5"|'''Archiving Utilities:'''|'''Service Management Utilities:'''||- valign="top"|*[http://linuxmanpages.com/man1/tar.1.php tar]*[http://linuxmanpages.com/man1/gzip.1.php gzip]*[http://linuxmanpages.com/man1/gunzip.1.php gunzipzip]* Completion of Labs [http://linuxmanpages.com/man1/make.1-4.php make]|*[http://www.linuxcertif.com/man/1/systemctl/ systemctl]

==Investigation 1: How do you create and use a filesystem in a regular file?Resources on the web==Additional links to tutorials and HOWTOs:* [http://www.centos.org/docs/2/rhl-gsg-en-7.2/s1-zip-tar.html archiving with tar, gzip, gunzip]* [http://www.tuxfiles.org/linuxhelp/softinstall.html Compiling Software from Source Code]* [[init vs systemd]]

{{Admon==Archiving Files /note|Use fedora3|Perform these steps in the '''fedora3''' virtual machine.}}Compiling Software from Source Code==

#Login using your Learn ID#Create an empty file that is exactly 3 MB in size:#*<code>dd if=/dev/zero of=/tmp/fstest bs=1k count=3072</code>#How does this command ensure that the file is 3 MB in size? What is in the file at first?#Create an ext3 filesystem within the newly-created file <code>/tmp/fstest</Archive files are often used to contain source code>. Note the warning message/question that appears#Mount the filesystem (remember to use the loopback optionfor software; refer to Lab 1 if required). Use a mountpoint of your choosing.#Copy the files <code>/etc/services</code> and <code>/etc/protocols</code> to the filesystem mounted in the previous step#Unmount the filesystem#Test your filesystem to this lab you will also be sure that the files <code>/etc/services</code> and <code>/etc/protocols</code> were in fact copied into the filesystem within the file named <code>/tmp/fstest</code>. #How much space is left in that filesystem? (Hint: <code>df -h</compiling software from a source code>)archive.

Make sure that your {{Admon/note|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 notes answer the Investigation 1 question.|}}

===Investigation 21: How do you create an archive file?===

{{Admon/important | Warning! | Don#Boot up your 't miss the '''.fedora3''' at the end of the <code>tar</code> commands below! It specifies what should go into the archive: the contents of the current directoryVM.}}

{{Admon/important | Warning! | Don't miss the '''.''' at the end of the <code>tar</code> commands below! It specifies what should go into the archive: the contents of the current directory.}} <ol> <li value="4">What do the options c, v, and f mean?</li> <li>Record the archive file size.</li> <li>Compress the file using <code>gzip</code>: <ul> <li><code>gzip /tmp/archive1.tar</code></li> </ul> </li> <li>Record the archive file size after compression.</li> <li>Make sure you're still in <code>/usr/share/doc/sudo*</code> and then create a compressed archive:<ul> <li><code>tar cvzf /tmp/archive2.tgz .</code></li> </ul> </li> <li>What does the <code>z</code> option do?</li> <li>Compare the sizes of <code>/tmp/archive1.tar.gz</code> and <code>/tmp/archive2.tgz</code>. Why are they so close in size?</li></ol> '''Answer the Investigation 2 question1 observations / questions in your lab log book.'''

===Investigation 32: How do you restore files from an archive?==={{Admon/note|Use Remain in your fedora3VM|Perform these steps in the '''fedora3''' virtual machine.}}#Create the directory <code>/tmp/extract1</code> and make it #Change to the <code>/tmp/extract1</code> directory.#Move the file archive1.tar.gz to your current working directory (change into that directory).

#*<code>gunzip /tmp/archive1.tar.gz</code>

#*<code>tar xvf /tmp/archive1.tar</code>

#Create the directory <code>/tmp/extract2</code> and make it your current working #Move the file archive2.tgz to the <code>/tmp/extract2</code> directory.

#*<code>tar xvzf /tmp/extract2/archive2.tgz</code>

'''Answer the Investigation 3 question2 observations / questions in your lab log book.'''

{{Admon/important|Compiling requires the correct tools to be installed. | 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. In Fedora, the command <code>yum groupinstall "Development Tools" "Development Libraries"</code> will install a basic set of development tools and libraries. '''You may need to install additional tools or libraries in order to compile a particular software package.'''}} #Go to the directory <code>/tmp</code>#Use the <code>wget</code> command to download the "tar ball" that contains the source code for the NLED text editor. <code>wget</code> is a command-line tool to download files from the web using the http or ftp protocols.#*<code>wget http://cdot.senecac.on.ca/software/nled/nled_2_52_src.tgz</code>#Extract the files. Change to the newly-extracted directory (<code>/tmp/nled-2.52</code>)#Check to see if there is a file named <code>configure</code>. 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 <code>Makefile</code> or <code>makefile</code>. If so, type the command:#*<code>make</code>#What does <code>make</code> do?#Some software distributed as source code can automatically install itself. Try this command:#*<code>make install</code>#Most but not all source code archives include the capability of installing themselves this way.# If the command <code>make install</code> does not work (how can you tell?), copy the <code>nled</code> program manually:#*<code>cp nled /usr/local/bin</code>#Test <code>nled</code> to make sure it works.

Answer #Boot up your '''fedora2''' VM. <!-- corrected a couple typos Eric D.--># Issue the Investigation 4 question.following command to install a basic set of development tools and libraries:<br /><code>yum groupinstall "Development Tools" "Development Libraries"</code>

{{Admon/note|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}} <ol> <li value="3">Go to the directory <code>/tmp</code></li> <li>Use the <code>wget</code> command to download the "tar ball" that contains the source code for the NLED text editor. <code>wget</code> is a command-line tool to download files from the web using the http or ftp protocols. <ul> <li><code>wget http://cdot.senecac.on.ca/software/nled/nled_2_52_src.tgz</code></li> </ul> </li> <li>Extract the files. Change to the newly-extracted directory (<code>/tmp/nled-2.52</code>)</li> <li>Check to see if there is a file named <code>configure</code>. If so, run it; if not, skip this step. (Most but not all source code archives contain this file)</li> <li>Check to see if there is a file named <code>Makefile</code> or <code>makefile</code>. If so, type the command: <ul> <li><code>make</code></li> </ul> <li>What does <code>make</code> do?</li> <li>Some software distributed as source code can automatically install itself. Try this command: <ul> <li><code>make install</code></li> </ul> </li> <li>Most but not all source code archives include the capability of installing themselves this way.</li> <li>If the command <code>make install</code> does not work (how can you tell?), copy the <code>nled</code> program manually: <ul> <li><code>cp nled /usr/local/bin</code></li> </ul> </li> <li>Test <code>nled</code> to make sure it works.</li></ol> '''Answer the Investigation 3 observations / questions in your lab log book.''' ==Managing Run-Levels and System Services== ===Investigation 54: How do we turn system services on and offManage Runlevels?===

{{Admon/important| Security Advice | We have seen that maintaining unneeded packages can be The runlevel command is now deprecated in Fedora, and has been replaced by '''systemctl'''. The newer system called '''systemd''' is a security risk due 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.<ol> <li>Issue the following Linux command: <ul> <li><code>systemctl list-units --type=target</code></li> </ul> </li> <li>Note the unnecessary increase in target labelled graphical. Now trace the complexity chain of your links starting at /etc/systemd/system/default. Similarly, target - what's it is ultimately pointing to?</li> <li>Issue the following commands to switch the default mode (also unnecessarily hazardous, and even more soknown as target, formerly runlevel): <ul> <li><code>rm /etc/systemd/system/default.target</code></li> <li><code>ln -s /lib/systemd/system/multi-user.target /etc/systemd/system/default.target</code></li> </ul> <li>Restart your fedora2 VM. What happens?</li> <li>Log into your regular user account.</li> <li>Issue the following Linux command: <ul> <li><code>startx</code></li> </ul> </li> <li>What happens?</li> <li>Log-off your graphical system. You should return to leave unneeded services runningyour shell prompt.</li> <li>Issue the following commands: <ul> <li><code>rm /etc/systemd/system/default.target</code></li> <li><code>ln -s /lib/systemd/system/graphical.target /etc/systemd/system/default. In this investigation, we will learn how to control services, and turn off those that we think are not necessarytarget</code></li> </ul> </li> <li>Reboot your fedora2 VM.}}What Happens?</li></ol>

#Determine your current runlevel using the <code>runlevel</code> command.#Change to '''Answer the appropriate startup directory in a terminal window. For example, if your runlevel is Investigation 4, change to <code>observations /etc/rc.d/rc4.d</code>#Observe the names of the symbolic links questions in that directory. #Where do the links link to?#Run the menu option <code>System>Administration>Services</code>. You will then see the Service Configuration screen.#Find the <code>bluetooth</code> service and select customize from the tool bar. and deselect the checkbox for your runlevel from step 1lab log book. Quit the app.#Return to the terminal window you used in Step 2. Get a listing of the symbolic links in the startup directory. Is it any different from what you observed previously?#Using the Service Configuration screen, re-enable the <code>bluetooth</code> service. #Check the symbolic links again. What has changed this time?#Run this command:#*<code>chkconfig bluetooth off</code>#Now what has changed in the directory?#Run this command:#*<code>chkconfig bluetooth on</code>#Now what has changed?#Run the command:#*<code>chkconfig --list</code>#What does the output show?#What is the relationship between the Service Configuration tool, the symbolic links in the startup directory, and the <code>chkconfig</code> command?#You can also use <code>chkconfig</code> to set services to be on or off for certain runlevels. For example, to turn httpd on for runlevel 4, we issue the command:#*<code>chkconfig --level 4 httpd on</code>#To turn it off, we type:#*<code>chkconfig --level 4 httpd off</code>#To increase your computer's security, make sure these services are disabled:#*btseed, bttrack, cups, irda, mdmonitor, netfs, nfs, nfslock, pcscd, rpcgssd, rpcidmapd, rpcsvcgssd, sendmail, ypbind.{{Admon/note|Carefull|You should understand that while most services in this list are often not needed, or are needed under circumstances different than those which occur here, there may be situations in which some of them are required, and it may be up to you as an administrator to determine which services are needed, and which should be turned off.}}''

Answer the === Investigation 5 question.: How do we Manage System Services? ===

==Investigation 6: How do we automatically mount a new partition {{Admon/note|Remain in Fedora?==your fedora2 VM|Perform these steps in the '''fedora2''' virtual machine.}}

{{Admon/note|Use fedorahost |Perform these steps on the We have seen that maintaining unneeded '''Fedora Hostpackages can be a security risk''' (f13host).}}#Create due to the empty directory /lab5#Verify that unnecessary increase in the <code>/dev/sda5</code> partition complexity of your system. Similarly, it is not in usealso unnecessarily hazardous, and even more so, then reformat <code>/dev/sda5</code> as ext3#Check the man page for <code>/etc/fstab</code> by entering the command <code>man fstab</code>#Edit your <code>/etc/fstab</code> file to mount the partition <code>/dev/sda5</code> leave unneeded services running. In this investigation, we will learn how to <code>/lab5</code>#Issue this command:#*<code>mount -a</code>#What does '''control services, and turn off those services that command do?#Confirm that the partition mounted and copy some files we think are not necessary to ithelp reduce security risks'''.}}

<ol> <li>Issue the following Linux command: <ul> <li><code>systemctl list-units --type=service</code></li> </ul> </li> <li>Note the services that are currently running.</li> <li>Refer to the tutorial ([[init vs systemd]] ) to learn how to use the systemctl command to stop the service named '''iptables'''</li> <li>Issue the systemctl command to verify that this service has stopped.</li> <li>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 disable the service. Refer to the tutorial ([[init vs systemd]] ) to learn how to use the systemctl command to disable the service named '''iptables'''</li> <li>Reboot and confirm that it's no longer running.</li></ol> '''Answer the Investigation 6 question5 observations / questions in your lab log book.'''

#[ Compressed files: ] <code>/tmp/fstestarchive1.tar.gz</code> filesystem counted with files copied to itand <code>/tmp/archive2.tgz</code>#[ ] <code>nled</code> application is installed#[ ] Correct services are disabledLab5 notes how to use systemctl commands#[ ] <code>/lab5</code> has an entry in <code>/etc/fstab</code>VMs backed-up

==Preparing for the Quizzes==

#How do you ensure that a filesystem What is mounted every time the system is started?#How is creating and using a filesystem in a file different from creating and using a filesystem in a block device (such as purpose of a partition)repository?

#How do you use <code>chkconfigsystemctl</code>?to:#The startup directory for each *list runlevel contains symbolic links. Where are the targets of the symbolic links#*list services#*stop a service#*start a service#*Why is it important to learn how to manage services?#When you use the menu option System>Administration>Services, what program *Why is runit important to stop certain services?