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'''A few common problems are:'''
*I Can't boot into Graphical Mode on my '''centos1c7host''' machine
*I Forgot My '''Regular User''' Password
*I Forgot My '''root''' Password
#Select Open Virtual Machine, and select the VM called c7host on your Solid State Drive.
#Launch your c7host machine, and login as as a regular user.
#Boot-up your '''centos1c7host''' VM. '''when the Grub Boot menu appears''', press the letter <b><code><span style="color:#3366CC;font-size:1.2em;">e</span></code></b> (for "edit").
#Using your arrow keys, scroll to next screen to '''linux''', or '''linux16''', or '''linux-efi''' command and type the word <b><code><span style="color:#3366CC;font-size:1.2em;">single</span></code></b> as an argument after '''quiet''' (see diagram for reference) and then press <b><code><span style="color:#3366CC;font-size:1.2em;">ctrl-x</span></code></b> to boot.
#The system should boot into text-based mode. Enter your '''root''' password.
'''Catastrophic Boot Problems:'''
:Not being able to start your '''centos1c7host''' due to '''Kernel Panic''' or some sort of '''catastrophic disk failure''' is not as easy to fix. You might be able to boot from your '''Centos LIVE DVD, open a terminal and mount the partition''' via command line and look for possible problems (setup files like '''/etc/fstab'''). '''Lab5''' will discuss more about mounting and the /etc/fstab file. The "worst-case scenario" would be to purchase a new hard disk, '''perform lab1 completely, perform lab2 to install and set-up virtualization software''', then '''restore your VM image and xml file backups''' (eg. decompressing images, issuing virsh define commands for .xml files). That is why consistently '''performing backups of ALL of your VMS at the end of each lab is absolutely essential! You have been warned!'''
'''Answer Investigation 2 observations / questions in your lab log book.'''
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#Perform this section in your '''centos1c7host''' machine.
#Issue the command: <b><code><span style="color:#3366CC;font-size:1.2em;">yum install elinks</span></code></b>
#Now issue the command: <b><code><span style="color:#3366CC;font-size:1.2em;">yum info elinks</span></code></b>
<ol>
<li value="14">We will now look at how we can add different repositories to our '''centos1c7host''' machine.</li><li>As root, issue the following command: <b><code><span style="color:#3366CC;font-size:1.3em;">yum repolist</span></code></b></li><li>Take a few moments to view the contents of the file. Do you see which repositories are used by the '''yum''' command? Write down the repositories in your lab logbook.</li><li>View the following link to see a general listing of repositories:<br>[ [http://wiki.centos.org/AdditionalResources/Repositories Available Repositories for Centos] ].</li><li>To add this repository, issue the command:<br><b><code><span style="color:#3366CC;font-size:1.3em;">wget https://dl.fedoraproject.org/pub/epel/7/x86_64/e/epel-release-7-5.noarch.rpm</span></code></b></li><li>To enable the repository in yum, issue the following command:<br><b><code><span style="color:#3366CC;font-size:1.3em;">yum install epel-release-7-5.noarch.rpm</span></code></b></li><li>To clean-up the repository list (including downloading new applications in added repositories), issue the command: <b><code><span style="color:#3366CC;font-size:1.3em;">yum clean all</span></code></b></li><li>To verify that you have added the repository, you can issue the command: <b><code><span style="color:#3366CC;font-size:1.3em;">yum repolist</span></code></b></li><li>Unused and unneeded software can present a security risk and ties up disk space needlessly. Find '''at least 4 other packages''' to remove on your centos1 c7host machine(for example: '''sound & video''', '''games''', etc) that you're not using on your system. Be careful to ensure that removing those packages does not also remove other software that you do need.</li>
</ol>
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.
# Remain in your '''centos1c7host''' VM, but make certain that you are logged in as a regular user (i.e. NOT root!).
# Perform a Netsearch for the pattern: <b><code><span style="color:#3366CC;font-size:1.2em;">lbreakout2 tar.gz</span></code></b>
# Go to aan appropriate webpage and download a "zipped tarball" (compressed source code) for the '''lbreakout2''' game (filename should be something like: '''lbreakout2.tar.gz''')
If you require <u>'''additional practice'''</u> in creating shell scripts using the "sed" utility, run the following command in your '''Matrix''' account:<br>'''/home/murray.saul/scripting-4'''
<br><br>
# Perform the following steps in your '''centos1c7host''' machine for this section.
# Open a Bash shell terminal and login as root.
# Use a text editor (such as <b><code><span style="color:#3366CC;font-size:1.2em;">vi</span></code></b> or <b><code><span style="color:#3366CC;font-size:1.2em;">nano</span></code></b>) to create a Bash Shell script called: <b><code><span style="color:#3366CC;font-size:1.2em;">packageInfo.bash</span></code></b> in root's home directory.
'''Perform the Following Steps:'''
# Make certain that your '''centos1c7host''' and '''centos4''' VMs are running.# Switch to your <u>'''centos1c7host'''</u> machine, open a shell terminal, and login as root.
# Issue the Linux command: <b><code><span style="color:#3366CC;font-size:1.2em;">wget http://matrix.senecac.on.ca/~murray.saul/ops235/lab3-check.bash</span></code></b>
# Give the '''lab3-check.bash''' file execute permissions (for the file owner).
# Run the shell script and if any warnings, make fixes and re-run shell script until you receive "congratulations" message.
#Arrange proof of the following on the screen:<br><span style="color:green;font-size:1.5em;">✓</span> '''centos4''' VM:<blockquote><ul><li> Archived files '''created'''</li><li>Archive files '''restored'''</ul></blockquote><span style="color:green;font-size:1.5em;">✓</span> '''centos1c7host''' Machine:<blockquote><ul><li> '''One repository added''' for yum</li><li>Output from running the '''lab3-check.bash''' script with all OK messages</li></ul></blockquote><span style="color:green;font-size:1.5em;">✓</span> '''Lab3''' log-book filled out.