{{Admon/caution|THIS IS AN OLD VERSION OF THE LAB|'''This is an archived version. Do not use this in your OPS235 course.'''}}

 '''In this lab, you will create three virtual machines'''. This also gives you an opportunity to experiment with different ways of installing CentOS. You will be learning the following elements of Virtualization in this lab:<br><br><u>Main Objectives</u> :* '''Installing Virtualization Software''' on your '''c7host ''' machine:* '''Create 3 separate VMs (virtual machines) using different installation methods:''':** Centos Live DVDInstallation:** Network Installation without configuration file:** Network Installation with configuration file (Kickstart)<br><br>:* Understand the '''advantages and disadvantages of each type of installation''', and be able to '''select the best installation method''' for a particular situation.:* '''Manipulate virtual machines by CLI''' (virsh):* '''Properly backup VMs and VM configuration''' in virtual manager application onto home directory and to external source (USB Key):* Observe how '''Bash Shell Scripting''' can be used to automate routine tasks involving VM management

A '''virtual machine''' is a software simulation of a computer which can be used as though it were actual hardware. It's possible to run multiple virtual machines on one computer, reducing hardware requirements and introducing promoting flexibilitywhen working with multiple operating systems. Some common uses of virtualization include:

== Minimum Required Materials (Bring to All Labs) ==

|width="1020%" |<u>Virtualization:</u>

|width="10%" |<u>Installation Guides</u> [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>[http://www.centos.org/docs/5/html/Installation_Guide-en-US/ch-kickstart2.html CentOS Kickstart Reference ]<br>|width="1020%" |<u>Commands</u>

|width="40%" |{{Admon/tip|Online Linux Command Review|The following links tutorial will allow you to practice Linux commands that you learned from ULI101learn essential shell scripting skills. Login to your '''Matrix''' account, and issue the pathname to run the online tutorial in Matrix:<br><ul> <li>Bash Shell Scripting Continued- 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>|

[[Image:lab2-logbook.png|thumb|right|100px200px|'''comparison chart''' in lab2 logbook.]]

You will be learning to perform several different type of CENTOS Linux installs. Lab2 already has an empty table for comparing various Linux installs. You were required in lab1 to record your observation for your '''c7host ''' installation.

# Install Open a shell terminal.<br><br>'''WARNING:''' You must perform a '''yum update''' on your '''c7host''' machine before proceeding with the next steps.<br><br># You will need to download an image file for the virtualization software Centos7 LIVE DVD by issuing the following command(best works while at Seneca):<br><b><code><span style="pointercolor:#3366CC;font-eventssize: none1.2em;cursor">wget http://belmont.senecac.on.ca/centos/7/isos/x86_64/CentOS-7-x86_64-LiveGNOME-1511.iso</span></code></b><br><br># Install the virtualization software by issuing the command: default;<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-viewerbridge-utils</span></code></b> <br><br> {{Admon/important|Restart your Host Machine|You must restart your '''c7host''' machine after installing the virtualization program above. If you fail to do this, you may experience virtualization network problems!}} 

:::* A graphical tool for managing virtual machines ('''virt-manager''') and the '''virsh''' command-line tool.<br><br>

<li value="35">Start the virtualization service: <b><code><span style="pointer-events: none;cursor: default;color:#3366CC;font-size:1.2em;">service libvirtd start</span></code></b></li> <li>The firewall configuration is altered by the addition of the virtualization software. Restart Centos7 uses firewalld for firewall, but we will be switching back to using iptables. Issue the following series of command to install iptables and restart the firewall so that these changes become active: <br><br> <b><code><span style="color:#3366CC;font-size:1.2em;">systemctl stop firewalld</span></code></b><br><b><code><span style="color:#3366CC;font-size:1.2em;">systemctl mask firewalld</span></code></b><br><b><code><span style="color:#3366CC;font-size:1.2em;">yum install iptables-services</span></code></b><br><b><code><span style="pointercolor:#3366CC;font-eventssize: none1.2em;cursor">systemctl enable iptables</span></code></b><br><b><code><span style="color:#3366CC;font-size: default1.2em;">systemctl start iptables</span></code></b><br><b><code><span style="color:#3366CC;font-size:1.2em;">service iptables restartsave</span></code></b><br><br></li>

<li value="57">Start the graphical tool by selecting the menu options '''Applications'''>'''System Tools'''>'''Virtual Machine Manager''' or by typing the command <b><code><span style="pointer-events: none;cursor: default;color:#3366CC;font-size:1.2em;">virt-manager</span></code></b></li>

== Part 1: Installing from a Downloaded Image (Centos7 LIVE CD) =={| width="40%" align="right" cellpadding="10"|- valign="top"|{{Admon/tip|Performing this Lab off the Perform Downloads and Network installs at Seneca network (eg. at home)|'''It is recommended to perform this lab in one of Seneca College's labs'''. This lab uses servers which are on the Seneca network and which are not available from other locations (such as your home). If you attempt this lab from another location, adjust the belmont.senecac.on.ca URLs to point to another mirror server -- note that you may need to change the directory name as well as the server name. The installation of the '''centos3''' virtual machine <u>must</u> be done at Seneca.}}|-|{{Admon/tipimportant|Removing and Recreating VMs|Using an Image instead of If for some reason the user wants to remove a Live Disc|Virtual Machine, they can right-click the VM, and select delete in the Virtual Machine Manager. It is recommended that you perform this installation from your Live DVD. As a matter of interest (for future reference), it is possible to install directly from '''"delete the ISO image file " in the remove VM dialog box when removing and then recreating a VM'''. Note: If you used fail to burn your Live DVDproperly remove the VM image file, it may affect the hard disk size for the new VM (i.e. There are many Internet tutorials that show use the individual how old smaller size. Make certain to perform remove that taskVM image file prior to recreating the VM.|'''}}|}

In {{Admon/important|Restart your Host Machine Again|You must restart your '''c7host''' machine again, prior to creating your virtual machines. If you fail to do this investigation, you will install CentOS from your live disc, and observe the differences between this type of installation and the DVD installation previously performed.may experience virtualization network problems!}}

==== :'''VM Details ====:'''

* :: '''VM Name(and hostname):''' centos1* :: '''Boot media:''' CentOS7 Live DVDLIVE CD Image* :: '''Installation source:''' Live DVDDownloaded Centos7 LIVE CD image (http://belmont.senecac.on.ca/centos/7/isos/x86_64/CentOS-7-x86_64-LiveGNOME-1511.iso):: '''VM Image Pathname:''' /var/lib/libvirt/images/centos1.img* :: '''Memory:''' 768MB2GB* :: '''Disk space:''' 10GB* :: '''File System (root partition):''' ext4:: '''CPUs:''' 1 ==== Steps ====

# '''Step 1 of 5:''' Enter the virtual machine (called Select '''centos1Local install media''') name and select click '''Local install mediaForward'''.# '''Step 2 of 5:''' Insert the DVD containing the Centos Live Disc image. Wait a moment for the disc to be recognized, then select Select '''Use CDROM or DVDISO Image''' as the install media. Set , click the ''OS type'Browse' to ''button, and then the 'Linux''Browse Local' and the ''Version'' button. Navigate to the location of the downloaded Centos7 LIVE CD image, select the image file and click '''Red Hat Enterprise Linux 7Open''' (the CentOS6 equivalent). When finished, click Forward to proceed.# '''Step 3 of 5:''' Set the memory to '''768 2048 MB''' and the number of CPUs to '''1'''# [[Image:vm-path.png|thumb|right|300px|It is extremely important to '''correctly specify the VM image file path-name'''. Double-check the spelling of the path-name before proceeding!]]<ol><li value="7">'''Step 4 of 5:''' This next step creates a disk file that will be used to simulate the virtual machine's disk drive. Select a size of '''10 GB''' and checkmark the box labeled . Click on<br> '''Allocate entire disk nowSelect managed or other existing storage'''# '''Step 5 of 5and type the VM image file pathame:<br> ''' Review the options that you have selected/var/lib/libvirt/images/centos1. img'''Make a note of (make certain that the storage location.pathname is correct) and then click ''' If anything needs to be changed, use the 'Forward'Back'' button to go back and edit it; otherwise, click proceed.</li><li>'''FinishStep 5 of 5:''' {{Admon/important|Removing and Recreating VMs|If for some reason Enter the user wants to remove a Virtual Machine, they can right-click the VM, and select delete in the Virtual Machine Manager. It is recommended to virtual machine name: '''"delete the image file" in the remove VM dialog box when removing and then recreating a VMcentos1'''. Note: If you fail to properly remove Review the VM image fileinformation, it may affect the hard disk size for the new VM (i.e. use the old smaller size. Make certain to remove that VM image file prior to recreating the VM.|and click '''Finish'''}} .<br><br><ol/li> <li value="8">'''The virtual machine will now start'''- start timing your installation and making notes for '''centos1''' virtual machine in the installation comparison chart in lab2 logbook. The virtual machine is running from the live disc at this point, and no software has been installed on the ''hard drive'' of the virtual machine. The point of a live disk is to allow you to test the distribution to see whether you like it without installing to the harddrive hard-drive first.</li><li>Double-click '''Install to Hard Drive'''. The installation program, similar to the one used when installing CentOS in Lab 1, will appear. You basically perform the same installation operations for this VM including for '''Date & Time''', '''Network & Hostname''', and '''Installation Destination'''. Make certain to use the '''hostname''': '''<u>centos1</u>''' as opposed to ''c7host'') for this installation. (with a few slight differences).</li><li>For '''Installation Destination''', select the destination option: '''I will configure partitioning''' and then click '''Done'''. Make certain that the '''Partition Scheme''' is set to '''LVM''' and then click on the link: '''Click to Create Automatically'''. '''Done'''. Check to make certain that the root partition has file system type: '''ext4'''.</li><li>Accept the changes and then click '''Begin Installation'''.<ol type="a"><li>You will be required to make selections very similar to what you did in lab1.</li><li>While the system is installing, take a few minutes to record your observations (including slight differences with centos1 install as opposed to c7host install).</li><li>When the installation process is complete, note the time required to install this system and record in the installation comparison chart of your lab2 logbook.<br><br></li></ol></li><li>Power-off your Centos7 LIVE system.</li><li>You should notice that the Centos7 boot menu appears. Either press '''ENTER''' to start or wait for it to start automatically.</li><li>Finish the final steps in the setup process (like you did in lab1).</li><li>#You may want to turn off the screen-saver (like you did in Lab1): [http://zenit.senecac.on.ca/wiki/index.php/OPS235_Lab_1_-_CentOS7#Customizing_Your_Account How to Turn-off Screen Saver (lab1)]</li></ol>{| width="40%" align="right" cellpadding="10"|- valign="top"|colspan="2"|{{Admon/important|Network / Service Considerations|Please perform the tasks below in order allow these CentOS systems to be able to communicate with each other. '''Failure to properly perform these operations can cause problems in future labs'''.|}}|}

<li value="913">Click '''Install Enable SSH access to Hard Drive'''. The installation program, similar your virtual machine with these commands (semi-colon allows commands to the one used when installing CentOS be run in Lab sequence):<br /> <b><code><span style="color:#3366CC;font-size:1, will appear. You will get a warning at one point during 2em;">service sshd start; chkconfig sshd on</span></code></b></li> <li>Find out the installation process that IP address of your virtual machine and the disk name of your Ethernet network adaptor: <b><code><span style="May contain datacolor:#3366CC;font-size:1.2em;" or >ifconfig</span></code></b> </li> <li>Enter the following command on your virtual machine to create a firewall exception to allow ssh traffic into the machine:<br /> <b><code><span style="may need to be recolor:#3366CC;font-initializedsize:1.2em;" >iptables -I INPUT - this is simply a warning p tcp -s0/0 -d0/0 --dport 22 -j ACCEPT</span></code></b></li><li>If you are logged in as root, logout to your regular user account.</li><li>Confirm that you can ssh to your virtual machine from the virtual disk host (your main CentOS installation): <b><code><span style="color:#3366CC;font-size:1.2em;">ssh regularuserid@IPaddress</span></code></b> (where '''regularuserid''' is completely blankyour regular user login id, and it '''IPaddress''' is safe to proceed with the installation'''IP_ADDRESS''' of your '''centos1''' VM!).</li><li>Make certain to '''disable SELinux for centos1''' (refer to lab1)</li><li>Adjust your screen-saver settings and run a '''yum update''' on your centos1 VM before proceeding to ''Part 2''</li></ol>

== Part 2: Installing from the a Network =={| width="40%" align="right" cellpadding="10"|- valign="top"|colspan="2"|{{Admon/tipimportant|Authenticate to the network|The rest of this lab uses network access.''' Be sure to authenticate to the network using your browser before proceeding'''.}}|}

It is possible to install CentOS entirely from the network:: '''VM Name (and hostname):''' centos2:: '''Boot media:''' Network installation:: '''Installation source URL:''' http://belmont.senecac. In this investigation, you will install CentOS from a webserver on the internet.ca/centos/7/os/x86_64/:: '''VM Image Pathname:''' /var/lib/libvirt/images/centos2.img:: '''Memory:''' 2048MB:: '''Disk space:''' 20GB:: '''CPUs:''' 1

* # Create the VM (called '''centos2'Name:'') as you did with the ' centos2* 'c7host''Boot mediamachine, except for the following differences:<br><br><ol type="a"><li>Select ''' Network installation* Installation'''Installation using the installation source:URL displayed above.</li><li>When customizing your partitions, do the same operation that you did in centos1, but after automatically creating the partitions, reduce the size of the root LVM partition to ''' http://belmont.senecac.on.ca/centos/7/os/x86_64/* 8000 MB'''Memory:and add an LVM partition with a size of ''' 1024MB* 2000 MB'''Disk space(mount point:''' 20GB* /home'''CPUs, name:''' 1 ==== Steps ====# Create the VM (called home'''centos2, and make certain root and /home partitions have ''') as you did with the ext4''centos1'file system).</li><li>Don' virtual machine, except select network installation using t forget to install the installation source url displayed above.GNOME desktop here as you will need a GUI for Centos2<br><br></li></ol># Observe Complete the boot processinstallation. How is it different from booting from an optical disc Login to your regular user account, and perform a yum update for the centos2 VM (DVDreboot if required)?# Start the installation process (make . Make certain to use information in the ''VM Details'' section above)adjust your screen-saver settings if desired.# When Repeat the steps as you get did to the disk partitioning step, select '''Use All Space''' and enable start the checkbox labelled SSH service'''Review and modify partition layout, '''. If an dialog box displays a permissions problem, then click yes to proceed. On the next screen, change the logical volumes as follows:#* Reduce the size of the root LV set iptables to accept connections via ssh'''8000 MB, '''.#* '''Add a <u>logical volume</u> with a size of 2000 MB test connections between centos2 and a mountpoint of /homec7host''' (you can name it whatever you want, and use '''ext4disable SELinux''' as the file-system type(refer to lab1).# On the software selection screen, select '''Desktop'''.# Complete the installation. Record the time taken to install, and compare this to the time taken by the previous installations.Record this information your findings in the '''table contained Installation Comparison chart in Investigation 4'''lab2 logbook.

== Part 3: Installing from the a Network using a Kickstart File == === Introduction === When CentOS is installed using the techniques you have used so far, the user is asked a number of questions. In some situations, it is better to provide the answers to these questions in a file rather than answer them individually. This type of file is called a ''kickstart'' file.

==== :: '''VM details ====Name (and hostname):''' centos3:: '''Boot media:''' Network installation:: '''Installation source URL:''' http://belmont.senecac.on.ca/centos/7/os/x86_64/:: '''Kickstart File URL:''' http://matrix.senecac.on.ca/~andrew.smith/ops235/centos7-kickstart-v01.cfg:: '''VM Image Pathname:''' /var/lib/libvirt/images/centos3.img:: '''Memory:''' 2048MB:: '''Disk space:''' 15GB:: '''CPUs:''' 1

# Observe the installation. How is it different from booting from an optical disca downloaded image?# Complete the installation. 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.

# Take a look at the kickstart file (eg. view url in a webj-browser) to determine the root password as well as the name and password for the first user account.!

 # Repeat the steps as you did to '''Answer start the Investigation 1 observations / questions in your lab log book.SSH service''', '''set iptables to accept connections via ssh''', '''test connections between centos3 and c7host''', and '''disable SELinux'''(refer to lab1). == Part 4: Updating the VMs == {{Admon/important|Check # Remember that your graphical VMs are connected to Network|It centos3 is recommended when starting text-based interface only (no graphics). To recover from a graphical VMblank screen, check press a key (like the network icon SPACE key) to return to see if the system is connected. If it is NOT connected, select auto ethscreen display.}}  # In each VM, run this command: <b><code><span style="pointer-events: none;cursor: default;color:#3366CC;">yum update</span></code></b># Record the answers time taken to these questions in your log book:#* How long did it take install, and compare this to run on each VM? How many packages were updated?#* Why does it take longer in some VMs than others?  {{Admon/caution|Never Shutdown Computer During Upgrade|Your computer (host, vms) are at their most vulnerable when you perform an update. Always plan ahead for appropriate the time prior to performing an updatetaken by the previous installations. Shutting down Record your computer while performing an update may cause your computer not to boot! You have been warned!!!}}findings in the Installation Comparison chart in lab2 logbook.

{| width="40%" align="right" cellpadding="10"|- valign="top"|colspan="2"|{{Admon/note|Manage virtual machines from the host|The commands used to manage virtual machines must be executed on the host (your disk pack) and not inside a virtual machine.}}|}# 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="pointer-events: none;cursor: default;color:#3366CC;font-size:1.2em;">virsh list</span></code></b>#* :: <b><code><span style="pointer-events: none;cursor: default;color:#3366CC;font-size:1.2em;">virsh list --all</span></code></b>#* :: <b><code><span style="pointer-events: none;cursor: default;color:#3366CC;font-size:1.2em;">virsh list --inactive</span></code></b># {| width="40%" align="right" cellpadding="10"|- valign="top"|colspan="2"|{{Admon/note|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="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="pointer-events: none;cursor: default;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>

# Change to the directory <b><code>/var/lib/libvirt/images/</code></b>. Note the size of the files in this directory. What do these files contain?# Make a compressed backup of the <code>'''centos3.img</code> ''' file to your home directory with this command: <b><code><span style="pointer-events: none;cursor: default;color:#3366CC;font-size:1.2em;">gzip < centos3.img > ~YourUserId/centos3.img.backup.gz</span></code></b><br />(Note: Make certain to use the redirection signs "<" and ">" properly in the command!){{Admon/caution| Make sure # Compare the size of the backup is successful!|If there are any error messages, compressed and original files (hint: use '''DO NOTls -lh''' proceed past this point). YouIf file is very large (like 15GB), you didn're going t compress it and you need to destroy your centos3 virtual machine remove that file and restore it using the backup you have created -- if there are any problems with perform the backup, previous step until you will not have a working virtual machine, and will have to re-install get it.}}right!<ol> <li value="4">Compare the size of the compressed and original files.</li> <li># Start the '''''centos3''''' VM.</li> <li># '''Make certain that you are in your VM and <u>not</u> in your main system!'''</li> <li># Wreck <u>only</u> your centos3 system! Try this command inside the centos3 virtual machine: <b><code><span style="pointer-events: none;cursor: default;color:#3366CC;font-size:1.2em;">rm -rf /*</span></code></b></li>(ignore error messages). <li># Shut down the centos3 VM. If you tried to start the centos3 VM, it would not boot since all system files have been removed!</li> <li># Restore the original image from the backup in your home directory by typing this command: <b><code><span style="pointer-events: none;cursor: default;color:#3366CC;font-size:1.2em;">gunzip < ~YourUserId/centos3.img.backup.gz > centos3.img'''</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">Copy these files to the '''/var/lib/libvirt/images''' directory and decompress the image</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>Restart What happened in the virtual manager window? To remove a VMentry in the Virtual Manager window, simply issue the command: '''virsh undefine vm_name''' (without the '''. Is xml''' file extension)</li><li> Launch the VM to see if it working normally?boots-up</li> <li>Create compressed backups of Can you log into this VM? Perhaps your other virtual machinesinstructor will give you a clue in week #7... >;p<br><br></li></ol>{| width="40%" align="right" cellpadding="10"|- valign="top"|colspan="2"|{{Admon/tip|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.}}|}

<li value="12">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:<ol type="a"> <li>Execute the following command: <b><code><span style="pointer-events: none;cursor: default;color:#3366CC;">virsh dumpxml centos3 >centos3.xml</span></code></b></li> <li>Examine the file <b><code><span style="pointer-events: none;cursor: default;color:#3366CC;">centos3.xml</span></code></b>. What does it contain? What format is it in?</li> <li>Make a copy of <b><code><span style="pointer-events: none;cursor: default;color:#3366CC;">centos3.xml</span></code></b> called <code>centos3a.xml</code>.</li> <li>Edit the file <b><code><span style="pointer-events: none;cursor: default;color:#3366CC;">centos3a.xml</span></code></b>, making the following changes:</li></ol>::* Change the name (in the file, not the file name) to '''centos3a'''::* Change at least one of the hexadecimal characters in the UUID. Do not change the length of the UUID. Valid hexadecimal characters are 0-9 and a-f.<ol type="a" > <li value="6">Issue this command: <b><code><span style="pointer-events: none;cursor: default;color:#3366CC;22">virsh define centos3a.xml</span></code></b> <li>Issue the command <b><code><span style="pointer-events: none;cursor: default;color:#3366CC;">virsh list --all</span></code></b> and record any changes. <li>Issue the command: <b><code><span style="pointer-events: none;cursor: default;color:#3366CC;">virsh undefine centos3a</span></code></b> <li>List all of the virtual machines again, and note any changes. </li></ol> <li>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>

 {{Admon/important|Backing up VMs|It is essential <ol><li value="24">A previous OPS235 student graciously created a shell script that you can download and run to check to back up your VMs at the end of each see how you performed this lab, so (to see if you can easily restore them if something goes wrong in are on the right track).<br>Simply issue the next labcommand: <b><code><span style="color:#3366CC;font-size:1.2em;">wget http://matrix.senecac.on.ca/~murray.saul/ops235/lab2check2.}} {{Admonbash</span></tip|Shutting Down code></b> and run on your '''c7host machine'''.<br><br>'''If the Host while Virtual Machines are Running|If you shut down your host system while virtual machines are running, they will be suspendedshell script indicates any major errors, and will resume the next time you boot please inform your host systemOPS235 instructor or lab assistant to advise what to do'''.}}<br><br></li></ol>

[[Image:lab2_text_1.png{|width="40%" align="right" cellpadding="10"|thumb- valign="top"|right{{Admon/tip|275pxBash Shell Scripting Tips:|When executed as <br><ul><li>'''Data Input:'''<br><br>A shell script can obtain data from a number of methods: '''reading input files''', using '''rootarguments when issuing command''' (positional parameters), or '''prompting for data to store in a variable'''. The later method can be accomplished by using the '''sudoread''' command, provides VM status and opportunity to for example: '''read -p "Enter your name: " userName'''.<br><br></li><li>'''startMathematical Expressions:''' VMs <br><br>In shell scripting, data is stored in a variable as text-based interface]]#You may have learned about creating and running Bash Shell Scripts , not other data types (ints, floats, chars, etc) like in your ULI101 coursecompiled programs like C or Java. Shell scripts help Linux users and system administrators In order to have a shell script perform '''mathematical operations''', number or variable need to automatic repetitive tasks be surrounded by two sets of parenthesis '''((..))''' in order to become more efficient and convert a number stored as text to help them save timea binary number.#The <bbr><codebr>wget</codeu>'''Examples'''</bu> command can be used to quickly download files from the Internet. Issue the following command:<blockquotebr><bbr>''var1&#61;5;var2&#61;10''<codebr><span style=''echo "pointer-events: none;cursor: default;color:$var1 + $var2 &#3366CC61;$((var1+var2))"''<br>wget https<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></scsli><li>'''Loops (iteration):'''<br><br>Loops and logic are a very important elements of shell scripting (not to mention programming as well).senecacDeterminant 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 onunknown conditions (like waiting for user to enter correct data). Test conditions can be used with in-determinant loops, or even commands! If a command runs successfully (eg ls, cd, grep matching a pattern), zero (true) value is returned, otherwise a non-zero (false) value is returned.caCommand options or redirection to /'''dev/~murraynull''' can be used to just test if command runs, but not display stdout or stderr.saulConditional statements "and" (&amp;&amp;) /text-report"or" (&#124;&#124;) can also be used when testing multiple conditions.bash<br><br>'''<u>Examples (try in a shell script)</spanu>'''<br><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''</codebr></bbr>''read -p "enter a whole number: " num''</blockquotebr>''until echo $num &#Verify that the file 124; grep -q "^[0-9][0-9]*$"''<br>''do''<br> &nbsp;''textread -reportp "Incorrect.bashPlease enter WHOLE NUMBER: " num''<br>''done''<br><br>'' was downloaded to your current directory.#Assign read -p "pick a number between 1 and execute permissions for this file by issuing the command10: " num''<bbr>''while [ $num -lt 1 ] &#124;&#124; [ $num -gt 10 ]<codebr>''do''<br>chmod u+rx text&nbsp;''read -reportp "Incorrect.bashPlease pick number between 1 and 10: " num''<br>''done''<br><br></codeli></bul>}}#Run this |} You will continue our use of Bash Shell scripting by first creating a Bash Shell script by issuing 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 commandto start and stop your virtual machines. If you require <u>'''additional practice'''</u> in creating shell scripts using logic, loops and mathematical operations, run the commands in your '''Matrix''' account: <bul><codeli>'''/home/murray.saul/textscripting-report2'''</li><li>'''/home/murray.bashsaul/scripting-3'''</codeli></bul> Perform the following steps in your c7host machine: #Check to see if it created Open a report in your current directoryBash shell terminal and login as root. What is the purpose of the report?#Use the a text editor (such as <b><code><span style="color:#3366CC;font-size:1.2em;">vi</bspan> text editor to view the contents of the file <b/code>text-report.bash</b>. Can you understand how this script works?or <brb><brcode><span style="color:#Use the <b3366CC;font-size:1.2em;">nano<code/span>wget</code></b> command ) to download, study, and run the following shell scripts on-linecreate a Bash Shell script called:<blockquote><b><code><span style=" pointercolor:#3366CC;font-eventssize:none1.2em;cursor">backupVM.bash</span></code></b> in /root's home directory.# Enter the following text content into your text-editing session:default;<code style="color:#3366CC;font-family:courier;font-size:.9em;margin-left:20px;">https:<br>&#35;!/bin/scsbash  &#35; backupVM.senecac.onbash<br>&#35; Purpose: Creates system info report<br>&#35;<br>&#35; USAGE: .ca/~murray.saul/report.bash<br>https&#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 /scs.senecac.on.caroot" >&2<br>&nbsp;exit 1<br>fi</~murraycode><br><ol><li value="4">Save your editing session, but remain in the text editor.saul</report3li><li>This shell script is designed particularly for your centos1, centos2, and centos3 VMS.bash</spanli><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</codeli></bol></blockquotebr><code style="color:#Try to understand what these Bash Shell scripts do3366CC;font-family:courier;font-size:.9em;"> read -p "Backup all VMs? (y|n):" answer #You have completed lab1. Proceed prompt if all VMs to Completing The Lab, and follow the instructions for "lab signbe backed-off".up

'''Answer the Investigation 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$num.img > /root/centos$num.img.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 observations ): " numanswer<br>&nbsp;until echo $numanswer | grep "^[123]$" >> / questions in your lab log bookdev/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.img > /root/centos$numanswer.img.backup.gz<br><br>&nbsp;echo "VM #$numanswer BACKUP DONE":<br>else<br>&nbsp;echo "Invalid Selection...'''Aborting program"<br>&nbsp;exit 2<br>fi

 <ol><li value= Preparing "7">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 all observations / questions in your lab log book.''' = LAB 2 SIGN-OFF (SHOW INSTRUCTOR) ={{Admon/important|Time for a new backup!|If you have successfully completed this lab, make a new backup of your virtual machines as well as your host machine.}} '''Arrange proof of the following on the screen:''' <ol><li><span style="color:green;font-size:1.5em;">&#x2713;</span> '''<u>All</u> VMs''':<blockquote><ul><li>Working virtual machines '''created''' and '''running'''</li><li>'''Disk layout''' and '''size''' correct on all virtual machines</li><li> Proof of '''yum updates'''</li><li>'''All virtual machines backed-up''' (eg. usb stick and/or home directory)</li></ul></blockquote></li><li><span style="color:green;font-size:1.5em;">&#x2713;</span>'''c7host''' machine:<blockquote><ul><li>'''Correct VM image filenames''' contained in '''/var/lib/libvirt/images directory'''</li><li>Creation of your bash shell script called '''backupVM.bash'''</li><li>A list of your '''iptables''' rules (command: '''iptables -L''')</li></ul></blockquote></li><li><span style="color:green;font-size:1.5em;">&#x2713;</span> Lab2 logbook notes and '''Installation Comparison chart''' completed</li></ol> == Practice For Quizzes , Tests, Midterm &amp; Final Exam ==

# Which factors recorded in your table (above) were due to What is the type name of the file created by the CentOS installation performed, and which factors were due to the amount of software installedprogram?

# What is the purpose of procedure to backup your VM images (and relationship between these pieces of softwareXML config files) to your USB key?#* libvirt#* libvirtd#* virsh#* virt-manager#* virt-install#* kvm