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#REDIRECT [[OPS235_Lab_2_-_CentOS7_-_SSD2]]
 
 
 
 
= LAB PREPARATION =
 
[[Image:Vmware-1a-alt.png|thumb|right|400px|At the end of lab2, your VMware Workstation application will contain '''4 virtual machines''' ('''c7host''' in your '''VMware Workstation''' application, and '''centos1, centos2, centos3 VMs''' in your '''KVM''' application). You will now have the option to run one virtual machine at a time, or run all machines simultaneously to learn about networking (covered in later labs) ]]
 
 
 
=== Purpose / Objectives of Lab2===
 
 
 
In this lab, you will create 3 virtual machines within your host machine using another virtualization program called '''KVM'''. These VMs will be used throughout the remainder of this course to learn how to administer them (installing software, managing services, networking, etc).
 
 
 
While you are performing this lab, it is recommended to generally note the major differences in the different installation methods, and which method you prefer to use if you were a Linux system administrator in charge of installing many Linux distributions for an organization.
 
 
 
 
 
<br><br>
 
<u>Main Objectives</u>
 
 
 
* Installing additional Virtualization Software on your '''c7host''' machine ('''KVM''')
 
* '''Create 3 separate VMs (virtual machines) using different installation methods:'''
 
:* '''centos1''': Network Centos Installation ('''Graphical''')
 
:* '''centos2''': Network Centos Installation (minimal install - '''CLI only''')
 
:* '''centos3''': Network Centos Installation with Kickstart configuration file ('''CLI only''')
 
* Manipulate virtual machines by CLI ('''virsh''')
 
* Properly '''backup VM images''' and backup '''VM configuration files'''
 
* Create and run '''Bash Shell scripts''' to automatically create a post-install report for an installed VM.
 
 
 
 
 
{|width="100%" cellspacing="0"
 
 
 
|- valign="top"
 
 
 
|colspan="3" style="font-size:16px;font-weight:bold;border-bottom: thin solid black;border-spacing:0px;padding-left:20px;"|Minimum Required Materials<br>
 
 
 
|colspan="3" style="font-size:16px;font-weight:bold;border-bottom: thin solid black;border-spacing:0px;padding-left:20px;"|Linux Command Reference<br>
 
|- valign="top"
 
 
 
| |[[Image:harddrive.png|thumb|left|75px|<b>Removable SATA Hard Disk</b>]]
 
 
 
| |[[Image:ubs-key.png|thumb|left|85px|<b>USB key</b><br>(for backups)]]
 
 
 
| |[[Image:log-book.png|thumb|left|70px|<b>Lab2 Log Book</b>]]
 
 
 
| valign="top" style="padding-left:20px;"|
 
Virtualization<br>
 
[http://linux.die.net/man/1/virt-manager virt-manager]<br>
 
[http://linux.die.net/man/1/virsh virsh]<br>
 
Installation Guides<br>
 
[http://wiki.centos.org/HowTos/KVM Installing &amp; Using KVM on CentOS ]<br>
 
[http://www.dedoimedo.com/computers/kvm-intro.html Using KVM (tutorial)]<br>
 
[https://www.centos.org/docs/5/html/5.2/Virtualization/sect-Virtualization-Commands_for_Red_Hat_Virtualization-virsh_the_command_line_interface_tool_for_virtualization.html virsh command reference ]<br>
 
|valign="top"  style="padding-left:20px;"|
 
Miscellaneous<br>
 
[http://linuxcommand.org/lc3_man_pages/gzip1.html gzip , gunzip]<br>
 
[http://man7.org/linux/man-pages/man1/grep.1.html grep]<br>
 
[http://man7.org/linux/man-pages/man1/wc.1.html wc]<br>
 
[http://man7.org/linux/man-pages/man1/pwd.1.html pwd]<br>
 
[http://man7.org/linux/man-pages/man1/ls.1.html ls]<br>
 
[http://man7.org/linux/man-pages/man1/more.1.html more]<br>
 
[http://man7.org/linux/man-pages/man1/file.1.html file]<br>
 
[http://man7.org/linux/man-pages/man1/wget.1.html wget]<br>
 
[http://man7.org/linux/man-pages/man1/chmod.1.html chmod]<br>
 
[http://ss64.com/vi.html vi]
 
|valign="top"  style="padding-left:20px;"|Matrix Online Tutorials:<br><ul><li>Shell Scripting - Part 2 (Logic & Math Expressions):<br>'''/home/murray.saul/scripting-2'''</li><li>Shell Scripting - Part 3 (Loops)<br>'''/home/murray.saul/scripting-3'''</li></ul>
 
 
 
|}
 
 
 
=INVESTIGATION 1: SETUP FOR VIRTUAL MACHINES=
 
 
 
 
 
===Part 1: Install KVM Virtualization Application===
 
 
 
We will now install the KVM package in order to create our VMs. We will also be starting several services (including iptables) and disabling the firewalld service. We will learn more about managing firewalls using iptables in lab6.
 
 
 
:'''Perform the following steps:'''
 
 
 
# Log into your c7host machine, and switch to root user.
 
# perform a software update on your '''c7host''' VM by issuing the following command: <b><code><span style="color:#C336699;font-size:1.2em;">yum update</span></code></b>
 
 
 
{{Admon/important |Yum Update Hangs|If you experience yum update "hanging" around item 689 of over 1200 packages, issue the following commands <b>(in a new terminal!)</b>:<br><source>pkill systemctl
 
yum clean all
 
yum update
 
</source>'''NOTE:''' Do NOT press '''&lt;ctrl&gt;c''' since it may cause your machine to cause a kernel panic when you restart your machine.}}
 
 
 
<ol><li value="3">As root, install the virtualization software by issuing the command:<br><b><code><span style="color:#3366CC;font-size:1.2em;">yum install qemu-kvm qemu-img virt-manager libvirt libvirt-python \<br>python-virtinst libvirt-client virt-install virt-viewer bridge-utils</span></code></b> <br><br></li>
 
<li>'''Restart your c7host machine'''. If you fail to do this, you may experience virtualization network problems.
 
{| width="40%" align="right" cellpadding="10"
 
|- valign="top"
 
|
 
{{Admon/note|About KVM|There are actually several key programs installed for virtualization using KVM:<ul><li>'''kvm/qemu''' - the hypervisor and other hardware emulation systems.</li><li>A system service named '''libvirtd''' that manages the VMs.</li><li>A graphical tool for managing virtual machines ('''virt-manager''') and the '''virsh''' command-line tool.</li></ul>}}
 
|}
 
</li><li>Start the virtualization service: <b><code><span style="color:#3366CC;font-size:1.2em;">systemctl start libvirtd</span></code></b><br><br>'''NOTE:''' The most recent variants of Centos and Fedora are using a service called '''firewalld''' that is intended to replace '''iptables''', however the ''iptables'' service is still in relatively common usage.  In this course we will concentrate on ''iptables''.<br><br></li>
 
<li>To Disable firewalld issue the following commands:<br>
 
<b><code><span style="color:#3366CC;font-size:1.2em;">systemctl disable firewalld</span></code></b><br>
 
<b><code><span style="color:#3366CC;font-size:1.2em;">systemctl stop firewalld</span></code></b><br>
 
<br></li>
 
<li>To install and enable the IPTables services, issue the following commands:<br>
 
<b><code><span style="color:#3366CC;font-size:1.2em;">yum install iptables-services</span></code></b><br>
 
<b><code><span style="color:#3366CC;font-size:1.2em;">systemctl enable iptables</span></code></b><br>
 
<b><code><span style="color:#3366CC;font-size:1.2em;">systemctl start iptables</span></code></b><br><br>
 
</li>
 
</ol>
 
{{Admon/important|Run virt-manager as a regular user, not as root|Otherwise all your virtual machines will be owned by root and you won't be able to use them as a regular user.}}
 
<ol>
 
<li value="8">Start the graphical tool by selecting the menu options '''Applications'''>'''System Tools'''>'''Virtual Machine Manager''' or by typing the command<b><code><span style="color:#3366CC;font-size:1.2em;"> virt-manager</span></code></b></li>
 
<li>You will be learning in the next investigation to perform several different type of CENTOS Linux installs.</li>
 
</ol>
 
 
 
'''Answer the INVESTIGATION 1 observations / questions in your lab log book.'''
 
 
 
=INVESTIGATION 2: INSTALL VIRTUAL MACHINES (KVM)=
 
 
 
 
 
=== Part 1: Installing VM from a Network (Graphical)===
 
 
 
:'''VM Details:'''
 
 
 
:: '''VM Name (and hostname):''' centos1
 
:: '''Boot media:''' Network installation
 
:: '''Centos Full Network Install URL:'''
 
:::*Seneca Lab: http://belmont.senecac.on.ca/centos/7/os/x86_64/
 
:::*Home: http://mirror.csclub.uwaterloo.ca/centos/7/os/x86_64/
 
:: '''VM Image Pathname:''' /var/lib/libvirt/images/centos1.qcow2
 
:: '''Memory:''' 2048MB
 
:: '''Disk space:''' 15GB
 
:: '''CPUs:''' 1
 
 
 
:'''Perform the following steps:'''
 
 
 
# Launch the ''KVM virtual machine manager'' by clicking '''Applications''' -> '''System Tools''' -> '''Virtual Machine Manager'''.
 
# When prompted, enter your '''root''' password.
 
# Click the '''create a new VM icon''' located near the top left-corner of the application window.
 
# Select the '''Network Install''' option and click '''Forward'''.
 
# Enter (copy and paste) the URL located at the top of this section (depending whether you are at Seneca College or not) and click '''Forward'''.
 
# Set RAM size to 2048 MB and click '''Forward'''.
 
# Set Hard Disk size to 15GB and click '''Forward'''.
 
# <span style="background-color:yellow;">Enter the name: '''centos1''', select the option: '''Customize configuration before install''', and click '''Finish'''.</span>
 
#<span style="background-color:yellow;">During the install, select '''Gnome Desktop''' software selection). For partitioning, select '''I will configure partition settings''', click done, then select '''Click here to create them automatically'''. Set the / partition for '''ext4''' file-system type, and click '''Done'''.</span>
 
#<span style="background-color:yellow;">Click on '''Network and Hostname'''. The network should be turned on. For hostname, enter: '''centos1''' and then click '''Done'''.</span>
 
# <span style="background-color:yellow;">Complete the installation. Login to your regular user account, and perform a '''yum update''' for the centos1 VM (reboot if required). Make certain to adjust your screen-saver settings if desired.</span>
 
<br>
 
{{Admon/important|Use same root password / regular username / regular user passwords for c7host and ALL VMs|To simplify the lab checking process make certain that you use the identical root password, regular username, and regular username password for VMs that you create in this labs as you did for c7host machine in lab1.<br><br>}}
 
<br>
 
<ol><li value="13"><span style="background-color:yellow;">Repeat the steps as you did in the previous investigation ([http://zenit.senecac.on.ca/wiki/index.php/OPS235_Lab_2_-_CentOS7_-_HD2#Part_1:_Install_KVM_Virtualization_Application Investigation1 Part 1]) to '''stop and disable firewalld, install iptables-services, start and enable iptables''' for this newly-created VM.</span></li>
 
<li><span style="background-color:yellow;">Repeat the steps as you did with c7host post-install to '''disable SELinux''' and perform a '''yum update'''.</span></li>
 
<li>Issue the following command to obtain the IPADDR for your centos1 VM to record in your lab2 logbook: <b><code><span style="color:#3366CC;font-size:1.2em;">ifconfig eth0</span></code></b></li>
 
<li>Record the time taken to install, and compare this to the time taken by the previous installations in your lab2 logbook.</li>
 
</ol>
 
 
 
=== Part 2: Installing from a Network (Minimal Install - CLI) ===
 
 
 
:'''VM Details:'''
 
 
 
:: '''VM Name (and hostname):''' centos2
 
:: '''Boot media:''' Network installation
 
:: '''Centos Full Network Install URL:'''
 
:::*Seneca Lab: http://belmont.senecac.on.ca/centos/7/os/x86_64/
 
:::*Home: http://mirror.csclub.uwaterloo.ca/centos/7/os/x86_64/
 
:: '''VM Image Pathname:''' /var/lib/libvirt/images/centos2.qcow2
 
:: '''Memory:''' 2048MB
 
:: '''Disk space:''' 20GB
 
:: '''CPUs:''' 1
 
 
 
:'''Perform the following steps:'''
 
 
 
# Create the VM (called '''centos2''') as you did with the ''centos1'' machine, except for the following difference<br><br><span style="background-color:yellow;">When customizing your partitions, do the same operation that you did in centos1 (but with '''Minimal Install''' software selection instead), but after automatically creating the partitions, reduce the size of the root LVM partition to '''8000 MB''' and add an LVM partition with a size of '''2000 MB''' (mount point: '''/home''', name: '''home''', and make certain root and /home partitions have '''ext4''' file system).</span><br><br>
 
# <span style="background-color:yellow;">Complete the installation. Login to your regular user account.</span>
 
#<span style="background-color:yellow;">Repeat the steps as you did in the previous investigation ([https://wiki.cdot.senecacollege.ca/wiki/OPS235_Lab_2_-_CentOS7_-_HD2#Part_1:_Install_KVM_Virtualization_Application Investigation 1 Part 1]) to '''stop and disable firewalld, install iptables-services, start and enable iptables''' for this newly-created VM.</span>
 
# <span style="background-color:yellow;">Repeat the steps as you did with c7host post-install to '''disable SELinux''' and perform a '''yum update'''.</span>
 
# The ifconfig command is not available in centos2. Issue the following command to obtain and record your centos2 IPADDR in your lab2 logbook: <b><code><span style="color:#3366CC;font-size:1.2em;">ip address</span></code></b>
 
# Record the time taken to install, and compare this to the time taken by the previous installations in your lab2 logbook.
 
 
 
=== Part 3: Installing from a Network using a Kickstart File ===
 
 
 
:'''VM Details:'''
 
 
 
:: '''VM Name (and hostname):''' centos3
 
:: '''Boot media:''' Network installation
 
:: '''Centos7 Full Install Network URL:'''
 
:::*Seneca Lab: http://belmont.senecac.on.ca/centos/7/os/x86_64/
 
:::*Home: http://mirror.csclub.uwaterloo.ca/centos/7/os/x86_64/
 
:: '''Kickstart File URL (Kernel options): ''' ks=http://matrix.senecac.on.ca/~andrew.smith/ops235/centos7-kickstart-v01.cfg
 
:: '''VM Image Pathname:''' /var/lib/libvirt/images/centos3.qcow2
 
:: '''Memory:''' 2048MB
 
:: '''Disk space:''' 15GB
 
:: '''CPUs:''' 1
 
 
 
:'''Perform the following steps:'''
 
 
 
# During the install, copy the network URL, then click the '''URL options''' to expand the '''kernel options''' input textbox. Type the following in the kernel options textbox:<br>'''<span style="color:#336699;font-weight:bold">ks=</span>http://matrix.senecac.on.ca/~andrew.smith/ops235/centos7-kickstart-v01.cfg''' and then click the '''forward''' button to proceed. Make certain to select the correct Memory Size and Disk Space size shown in the VM Details above.
 
# Observe the installation. How is it different from booting from a downloaded image?
 
# Record the time taken to install, and compare this to the time taken by the previous installations.<br><br>If the during the installation, you see the message at the bottom '''Pane is Dead''', click the '''Virtual Machine''' menu at the top, select '''Shut Down''' -> '''Force Off''', '''right-click''' on '''centos3''' in the ''virtual manager'' window and select '''Delete'''. Redo the VM setup for a new instance of the ''centos3'' VM.<br><br>
 
# What happens when the installation is finished?
 
# Click the kickstart file link in a web-browser, and record the following information to access your centos3 VM:<ul><li>'''Regular-user account name'''</li><li>'''Regular-user account password'''</li><li>'''Root Password'''</li></ul>
 
# Boot the virtual machine and log in (use the user ID and password information from the previous step to gain access to this VM).
 
# Compare the experience to the first time you booted the other virtual machines.
 
#<span style="background-color:yellow;">Repeat the steps as you did in the previous investigation ([http://zenit.senecac.on.ca/wiki/index.php/OPS235_Lab_2_-_CentOS7_-_SSD2#Part_2:_Install_KVM_Virtualization_Application Investigation1 Part 2]) to '''stop and disable firewalld, install iptables-services, start and enable iptables''' for this newly-created VM.</span>
 
# <span style="background-color:yellow;">Repeat the steps as you did with c7host post-install to '''disable SELinux''' and perform a '''yum update'''.</span>
 
# Issue the following command to obtain the IPADDR for your centos1 VM to record in your lab2 logbook: <b><code><span style="color:#3366CC;font-size:1.2em;">ifconfig eth0</span></code></b>
 
# Remember that centos3 is text-based interface only (no graphics). To recover from a blank screen, press a key (like the SPACE key) to return to the screen display.
 
# Record the time taken to install, and compare this to the time taken by the previous installations in your lab2 logbook.
 
 
 
 
 
'''Answer the INVESTIGATION 2 observations / questions in your lab log book.'''
 
 
 
=INVESTIGATION 2: MANAGING VIRTUAL MACHINES (KVM)=
 
 
 
 
 
{| width="40%" align="right" cellpadding="10"
 
|- valign="top"
 
|colspan="2"|{{Admon/important|Backing up VMs|There are two general processes in order to back up your images:<ol><li>'''Compressing your images''' (also recommended to backup up to external storage USB Key) using the '''gzip''' command.</li><li>'''Backup the VM xml configuration file''' (preferably to USB key) using '''virsh''' shell command to add VM to virtual machine manager list (in the event that the HOST machine is "wiped" and re-installed, but VM images and xml configuration files have been backed up external storage).</li></ol><br />Taking the time to backup the image of the Operating System's file system allows the user to return to a '''"restoration point"''' using the '''gunzip''' command in case something bad occurs to the OS during a lab.<br />Failure to take the time to make and confirm backups can result in loss of lab work for the student!|}}
 
|}
 
=== Part 1: Backing Up Virtual Machines ===
 
 
 
:'''Perform the following steps:'''
 
 
 
# Shut down your '''centos1''', '''centos2''', and '''centos3''' VMs. For ''centos2'' and ''centos3'', which are CLI-only, you can issue the following command as root to shutdown: <b><code><span style="color:#3366CC;font-size:1.2em;">shutdown -h</span></code></b>. Please be patient, the VMs will shut down!
 
# In your '''c7host''' VM, change to the images directory by issuing the command: <b><code><span style="color:#3366CC;font-size:1.2em;">cd /var/lib/libvirt/images/</span></code></b><br>Note the size of the files in this directory. What do these files contain?
 
# Make a compressed backup of your '''centos1.qcow2''' '''centos2.qcow2''', and '''centos3.qcow2''' files to your regular user's home directory by issuing each command (one at a time):<br><b><code><span style="color:#3366CC;font-size:1.2em;">gzip < centos1.qcow2 > ~YourRegularUsername/centos1.qcow2.backup.gz</span></code></b><br><b><code><span style="color:#3366CC;font-size:1.2em;">gzip < centos2.qcow2 > ~YourRegularUsername/centos2.qcow2.backup.gz</span></code></b><br><b><code><span style="color:#3366CC;font-size:1.2em;">gzip < centos3.qcow2 > ~YourRegularUsername/centos3.qcow2.backup.gz</span></code></b><br><br>
 
{{Admon/important |Please be patient|It may look like the command prompt is stuck but it could take a while for gzip to compress an entire operating system. '''NOTE:''' Do NOT press '''&lt;ctrl&gt;c''' to cancel this process. If you do, your archive will become incomplete and your recovery will be corrupt.}}
 
('''NOTE:''' Make certain to use the redirection signs "<" and ">" properly in the command!)<br><br>
 
# Compare the size of the compressed and original files (hint: use '''ls -lh'''). If file is very large (like 15GB), you didn't compress it and you need to remove that file and perform the previous step until you get it right!
 
# Start the '''''centos3''''' VM.
 
# '''Make certain that you are in your  VM and <u>not</u> in your main system!'''
 
# Wreck <u>only</u> your centos3 system! Try this command inside the centos3 virtual machine:<b><code><span style="color:#3366CC;font-size:1.2em;">rm -rf /*</span></code></b> (ignore error messages).
 
# Shut down the centos3 VM. If you tried to start the centos3 VM, it would not boot since all system files have been removed!
 
# Restore the original image from the backup in your home directory by typing this command:<br><b><code><span style="color:#3366CC;font-size:1.2em;">gunzip < ~YourUserId/centos3.qcow2.backup.gz > centos3.qcow2'''</span></code></b>
 
# Restart the VM. Is it working normally?
 
# Create compressed backups of your other virtual machines (ie. '''centos1''' and '''centos2''').
 
# You should make a copy of the xml configuration file in case you "wipe" and re-install the host machine, and want to add a restored VM backups to the virtual machine manager list. We will demonstrate using the centos3 xml configuration file, and prove that a "clone" can be added to your list.Please perform the following step:
 
# Execute the following command: <b><code><span style="color:#3366CC;font-size:1.2em;">virsh dumpxml centos3 > centos3.xml</span></code></b>
 
# Examine the file <b><code><span style="color:#3366CC;font-size:1.2em;">centos3.xml</span></code></b>. What does it contain? What format is it in?<br><br>
 
# We will now learn how to download a compressed image file and xml configuration file and add it as a VM to the virtual manager menu.
 
# Issue the following commands:<ul><li><b><code><span style="color:#3366CC;font-size:1.2em;">wget  http://cs.senecac.on.ca/~murray.saul/ops235/practical1.img.gz</span></code></b></li><li><b><code><span style="color:#3366CC;font-size:1.2em;">wget https://scs.senecac.on.ca/~murray.saul/ops235/practical1.xml</span></code></b><br><br></li></ul>
 
<ol><li value="17">The downloaded file "practical1.img.gz" is a "raw image compressed VM file", but will work the same for a Virtual Machine as the qcow2 file format.Copy these files to the '''/var/lib/libvirt/images''' directory and decompress that raw image file.</li><li>Make certain your present working directory is: '''/var/lib/libvirt/images'''</li><li>Issue the command: <b><code><span style="color:#3366CC;font-size:1.2em;">virsh define practical1.xml</span></code></b></li><li>What happened in the virtual manager window? To remove a VM entry in the Virtual Manager window, simply issue the command: '''virsh undefine vm_name''' (without the '''.xml''' file extension)</li><li> Launch the VM to see if it boots-up</li><li>Can you log into this VM? Perhaps your instructor will give you a clue in week #7...  >;p<br><br></li></ol>
 
{{Admon/important|Shutting Down the Host while Virtual Machines are Running|If you shut down your host system while virtual machines are running, they will be suspended, and will resume the next time you boot your host system.}}
 
<ol>
 
<li value="22">For the remainder of these labs, it is assumed that you will backup <u>'''both'''</u> the images and xml configuration files for <u>'''all'''</u> Virtual machines, when asked to backup your virtual machines. It is also highly recommended to backup these files to an external storage device (eg. USB key) in case the host machine gets "wiped" and you need to rebuild your HOST machine and then restore your Virtual Machines...</li>
 
<li>Answer this question in your log book:</li>
 
</ol>
 
::* In order to fully back up a virtual machine, what information should be saved in addition to the virtual machine image?
 
 
 
=== Part 2: Using Shell Scripts for VM Backup &amp; Management===
 
{|width="40%" align="right" cellpadding="10"
 
|- valign="top"
 
|
 
{{Admon/tip|Bash Shell Scripting Tips:|<br>'''<u>Data Input</u>'''<br><ul><li>A shell script can obtain data from a number of methods: '''reading input files''', using '''arguments when issuing command''' (positional parameters), or '''prompting for data to store in a variable'''. The later method can be accomplished by using the '''read''' command.<br><br></li><li>Example:<br><br>''read -p "Enter your name: " userName''.<br><br></li></ul>'''<u>Mathematical Expressions</u>'''<br><ul><li>In shell scripting, data is stored in variable as text, not other data types (ints, floats, chars, etc) like in compiled programs like C or Java. In order to have a shell script perform '''mathematical operations''', number or variable need to be surrounded by two sets of parenthesis '''((..))''' in order to convert a number stored as text to a binary number.<br><br></li><li>Examples<br><br>''var1&#61;5;var2&#61;10''<br>''echo "$var1 + $var2 &#61; $((var1+var2))"''<br><br>'''Note:''' shell does not perform floating point calculations (like '''5/10'''). Instead, other commands like '''awk''' or '''bc''' would be required for floating point calculations (decimals)<br><br></li></ul><u>'''Loops (for / while / until)'''</u><ul><li>Determinant loops (such as '''for''' loops) usually repeat for a preset number of times (eg. counts, positional parameters stored). In-determinant loops (such as '''while''' or '''until''' loops) may repeat based on unknown conditions (like waiting for user to enter correct data).<br><br></li><li>Conditional statements '''&amp;&amp;''' (run if previous command or test is true) and '''&#124;&#124;''' (run is previous command or test is false) can also be used when testing multiple conditions.<br><br></li><li>Examples:<br>''set ops235 is fun''<br>''for x''<br>''do''<br>&nbsp;''echo "argument is $x"''<br>''done''<br><br>''for x in $(ls)''<br>''do''<br> &nbsp;''echo "Filename: $x"''<br>''done''<br><br>''read -p "enter a whole number: " num''<br>''until echo $num &#124; grep -q "^[0-9][0-9]*$"''<br>''do''<br> &nbsp;''read -p "Incorrect. Please enter WHOLE NUMBER: " num''<br>''done''<br><br>''read -p "pick a number between 1 and 10: " num''<br>''while [ $num -lt 1 ] &#124;&#124; [ $num -gt 10 ]<br>''do''<br> &nbsp;''read -p "Incorrect. Please pick number between 1 and 10: " num''<br>''done''<br><br></li></ul>}}
 
|}
 
 
 
You will continue our use of Bash Shell scripting by first creating a Bash Shell script that will allow the Linux sysadmin to select their created VMs for backup to root's home directory. Afterwards you will download, view and run a couple Bash Shell scripts that use the virsh command to start and stop your virtual machines.
 
 
 
:'''Perform the following steps:'''
 
 
 
# Start the '''centos1''' virtual machine, and stop the '''centos2''' and '''centos3''' virtual machines.
 
# Switch to the '''c7host''' machine, and open a shell terminal.
 
# Enter these admin commands into your '''c7host''' machine and note the result:
 
:: <b><code><span style="color:#3366CC;font-size:1.2em;">virsh list</span></code></b>
 
:: <b><code><span style="color:#3366CC;font-size:1.2em;">virsh list --all</span></code></b>
 
:: <b><code><span style="color:#3366CC;font-size:1.2em;">virsh list --inactive</span></code></b>
 
<ol><li value="4">Now, shut-down your centos1 VM normally, and close the centos1 VM window.</li><li>Switch to your terminal and issue the command: <b><code><span style="color:#3366CC;font-size:1.2em;">virsh start centos1</span></code></b></li><li>Using the appropriate command check to see if your centos1 VM is now running.</li><li>There are other commands that can be used (such as '''suspend''', or '''shutdown'''). The "shutdown" command may not always work since it relies on the guest handling a particular ACPI event. Why do you think it is useful to have commands to manipulate VMs?</li><li>Since this is a text-based version of Linux, you do not need to turn off the screen-saver.</li></ol>
 
{{Admon/important|Virtual Machine Does not Shutdown from Command|If the Virtual machine fails to shutdown from the <code>virsh shutdown</code> command, then you can go to the '''Virtual Machine manager''' and  '''halt''' or '''shutdown''' within the VM itself, then you can click the '''PowerOff''' button in the VM window. You'll want to avoid a forced shutdown since those are equivalent to yanking the power cord out of the wall on a physical machine!|}}
 
<ol><li value="9">Open a Bash shell terminal and login as root.</li>
 
<li>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;">backupVM.bash</span></code></b> in /root's home directory.</li>
 
<li>Enter the following text content into your text-editing session:</li></ol>
 
<code style="color:#3366CC;font-family:courier;font-size:.9em;">
 
<br>
 
&#35;!/bin/bash
 
 
 
 
 
&#35; backupVM.bash<br>
 
&#35; Purpose: Creates system info report<br>
 
&#35;<br>
 
&#35; USAGE: ./report.bash<br>
 
&#35;<br>
 
&#35; Author: *** INSERT YOUR NAME ***<br>
 
&#35; Date:  *** CURRENT DATE ***
 
 
 
 
 
if [ $PWD != "/root" ]  # only runs if in root's directory<br>
 
then<br>&nbsp;echo "You must be located in /root" >&2<br>
 
&nbsp;exit 1<br>
 
fi
 
</code>
 
<br>
 
<ol>
 
<li value="12">Save your editing session, but remain in the text editor.</li><li>This shell script is designed particularly for your centos1, centos2, and centos3 VMS.</li><li>The code displayed below will prompt the user if they wish for all VMs to be backed-up; otherwise, allow the user the option of specifying which VMs to be backed-up. Add the following code</li></ol>
 
<br>
 
<code style="color:#3366CC;font-family:courier;font-size:.9em;">
 
 
 
read -p "Backup all VMs? (y|n):" answer  # prompt if all VMs to be backed-up
 
 
 
if [ "$answer" = "y" ]  # Backup all VMs if answer is yes<br>
 
then<br>
 
&nbsp;for num in 1 2 3  # Determinant loop for 3 arguments: 1, 2, and 3<br>
 
&nbsp;do<br>
 
&nbsp;&nbsp;echo "Backing up VM #$num"<br>
 
&nbsp;&nbsp;gzip < /var/lib/libvirt/images/centos$num.qcow2 > /root/centos$num.qcow2.backup.gz<br>
 
<br>&nbsp;&nbsp;echo "VM #$num BACKUP DONE"<br>
 
&nbsp;done<br><br>
 
elif [ "$answer" = "n" ]<br>
 
then<br>
 
&nbsp;read -p "Which VM should be backed up? (1/2/3): " numanswer<br>
 
&nbsp;until  echo $numanswer | grep "^[123]$" >> /dev/null  # Look for match of single digit: 1,2, or 3<br>
 
&nbsp;do<br>
 
&nbsp;&nbsp;read -p "Invalid Selection. Select 1, 2, or 3: " numanswer<br>
 
&nbsp;done<br>
 
&nbsp;echo "Backing up VM #$numanswer"<br>
 
&nbsp;gzip < /var/lib/libvirt/images/centos$numanswer.qcow2 > /root/centos$numanswer.qcow2.backup.gz<br><br>
 
&nbsp;echo "VM #$numanswer BACKUP DONE":<br>
 
else<br>
 
&nbsp;echo "Invalid Selection... Aborting program"<br>
 
&nbsp;exit 2<br>
 
fi
 
 
 
</code>
 
 
 
 
 
<ol>
 
<li value="15">Save, set permissions, and then run that shell script to backup centos1. Confirm that this script did backup this image to root's home directory</li><li>Use the <b><code>wget</code></b> command to download, study, and run the following shell scripts on-line:<blockquote><b><code><span style=" pointer-events:none;cursor:default;color:#3366CC;font-size:1.2em;">https://scs.senecac.on.ca/~murray.saul/vm-start-text.bash<br>https://scs.senecac.on.ca/~murray.saul/vm-stop-text.bash</span></code></b><br><b><code><span style=" pointer-events:none;cursor:default;color:#3366CC;font-size:1.2em;">https://scs.senecac.on.ca/~murray.saul/vm-start.bash<br>https://scs.senecac.on.ca/~murray.saul/vm-stop.bash</span></code></b></blockquote></li><li>Try to understand what these Bash Shell scripts do.</li><li>You have completed lab2. Proceed to Completing The Lab, and follow the instructions for "lab sign-off".</li></ol>
 
 
 
 
 
'''Answer INVESTIGATION 2 observations / questions in your lab log book.'''
 
 
 
 
 
= LAB 2 SIGN-OFF (SHOW INSTRUCTOR) =
 
{{Admon/important|Backup ALL of your VMs!|If you have successfully completed this lab, make a new backup of all of your virtual machines onto your UBS Key.}}
 
 
 
:'''Perform the Following Steps:'''
 
 
 
# Use the '''virsh start''' command to launch all the VMs ('''centos1''', '''centos2''', and '''centos3''').
 
# Switch to your '''c7host''' VM, open a terminal, login as root, and change directory to '''/root/bin'''.
 
# Issue the Linux command: <b><code><span style="color:#3366CC;font-size:1.2em;">wget http://matrix.senecac.on.ca/~murray.saul/ops235/lab2-check.bash</span></code></b>
 
# Give the '''lab2-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:
 
 
 
::&#x2713; '''<u>All</u> VMs''':<blockquote><ul><li>All 4 VMs '''created''' and '''running'''</li><li> Proof of '''yum updates''' on ALL VMs (i.e. results from '''yum update''' command)</li></ul></blockquote>
 
::<span style="color:green;font-size:1.5em;">&#x2713;</span>'''centos2 VM''':<blockquote><ul><li>Run the '''lab2-check.bash''' script in front of your instructor (must have all <b><code><span style="color:#66cc00;border:thin solid black;font-size:1.2em;">&nbsp;OK&nbsp;</span></code></b> messages)</li></ul></blockquote>
 
::<span style="color:green;font-size:1.5em;">&#x2713;</span> Lab2 logbook notes completed.
 
 
 
= Practice For Quizzes, Tests, Midterm &amp; Final Exam =
 
 
 
# What is the name of the CentOS installation program?
 
# What is the name of the file created by the CentOS installation program?
 
# Which type of installation works best for confirming compatibility with hardware before installation? Why?
 
# Which type of installation works best for installing large numbers of computers? Why?
 
# How can you reduce the number of software updates required immediately after installation?
 
# How do you start and stop virtual machines?
 
# How do you SSH into your virtual machines?
 
# List the steps to install a VM from:<ul><li>Downloaded iso file</li><li>Network install (without kickstart file)</li><li>Network install (with kickstart file)</li></ul>
 
# What is the purpose of the virsh command?
 
# How to start and stop VMs using the virsh command?
 
# List the steps to correctly backup your VMs to a USB disk
 
# List the steps to correctly restore your VMs from a USB disk to your c7host VM.
 
# How can you prompt the user for data and store into a variable?
 
# How do you perform mathematical operations in the Bash shell and within a Bash shell script?
 
# What is the difference between a determinant loop and an in-determinant loop?
 
# Show a few examples how loops can be used to error-check when prompting the user for data.
 
# What is the purpose of the '''&amp;&amp;''' and '''||''' symbols when used with logic?
 
 
 
 
 
[[Category:OPS235]]
 
[[Category:OPS235 Labs]]
 

Latest revision as of 06:29, 26 April 2018