Changes

= LAB PREPARATION CentOS Installation Methods (on Virtual Machines: centos1, centos2, centos3) =

== Purpose / Objectives A '''virtual machine''' is a software simulation of Lab2==[[Image:vmware-1a computer which can be used as though it were actual hardware.png|thumb|right|550px|The centos1 Linux server will run virtualization software It's possible to install and run 3 multiple virtual machines (installed in lab2)on one computer, reducing hardware requirements and introducing flexibility. ]]Some common uses of virtualization include:

:* '''In this labSoftware testing''' -- Using multiple operating systems simultaneously on a single computer for testing and experimentation.:* '''Network simulation''' -- Testing network services, protocols, you will create three additional and security scenarios with a small number of computers.:* '''Isolation''' -- Protecting multiple sets of data by storing them on multiple virtual machines. If one of the virtual machines is compromised, the data on other virtual machinesis still protected.:* '''Server consolidation''' -- Reducing the number of physical servers in a network by moving physical machines to virtual machines. This also gives you an opportunity saves hardware, administration, cooling, and electricity costs, and it can increase the utilization of hardware (by ensuring that the hardware is not under-loaded).:* '''Load-balancing and disaster recovery''' -- It is possible to experiment with migrate virtual machines between different ways of installing CentOS Linux virtual physical machines, to ensure that a workload is balanced across multiple computers, to allow routine hardware maintenance and upgrading, and to compensate for hardware failure or other disasters.<br><br><u>Main Objectives</u>

* {|cellpadding="8" width="100%"|- valign="top"| '''Create 3 separate VMs (In this lab, you will create three virtual machines) using different installation methods:'''. This also gives you an opportunity to experiment with different ways of installing CentOS. Later in this course you will install another operating system distribution in a virtual machine.:* Centos Live DVDInstallation:* Network Centos Installation without configuration file:* Network Centos Installation with configuration file (Kickstart)* Understand the You should already have both a '''advantages and disadvantages of each type of CentOS installationDVD1''', and be able to a '''select the best installation methodCentOS Live DVD''' for a particular situation.* '''Manipulate virtual machines by CLI'''* '''Properly backup VMs In both cases, the boot media (which you used to load the installation software) and VM configuration''' in virtual manager application onto home directory the installation source (the software that got installed) were the same: your DVD provides both. However, the CentOS (and most other Linux distributions) permits you to external source use any combination of boot media and installation media: |{|border="1" cellpadding="3" width="100%"|-! Method! Boot Media! Install. Source|-! CD or DVD! &#10003;! &#10003;|-! Hard Disk! &#10003;! &#10003;|-! USB Flash Drive! &#10003;! &#10003;|-! Network (USB Keyhttp/nfs repository)* Observe how '''Bash Shell Scripting''' can be used to automate routine tasks involving VM management! &#10003;! &#10003;|-! PXE Network Boot! &#10003;! X|} |}

{|cellpadding="15" width="40%"Required Materials (Bring to All Labs) ==

|- valign* CentOS 6.5 x86_64 Live DVD* CentOS 6.5 x86_64 Installation DVD1* SATA Hard Disk (in removable disk tray)* USB Memory Stick* Lab Logbook ==Prerequisites=="top"

|width==Linux Command Online Reference==Each Link below displays online manpages for each command (via [http://linuxmanpages.com/ http://linuxmanpages.com])::* '''virsh''' (Refer to CentOS Virtualization Guide link in the "10%Resources on the Web" |[section):* [Imagehttp:ubs-key//linuxmanpages.com/man1/gzip.1.png|thumb|left|85px|<b>USB key<php gzip /b><br>(for backups)]gunzip]

 == Resources on the Web =={|cellpadding="8" width="10100%" |- valign="top"| '''Virtualization''':| '''Network Installation:'''| '''Kickstart Installation:''' |- valign="top"|[http://www.centos.org/docs/5/html/Virtualization-en-US/ RedHat Virtualization Guide]|[Imagehttp:log//www.centos.org/docs/5/html/5.2/Installation_Guide/ RHEL Installation Guide]* [http://www.centos.org/docs/5/html/5.2/Installation_Guide/s1-steps-network-installs-books390.pnghtml Preparing for a Network Installation]* [http://www.centos.org/docs/5/html/5.2/Installation_Guide/s1-begininstall-perform-nfs-x86.html Performing a Network Installation]|thumb|left|70px|<b>Lab2 Log Book<[http://www.centos.org/docs/5/html/5.2/Installation_Guide/ RHEL Installation Guide]* [http://www.centos.org/docs/5/html/5.2/Installation_Guide/b>ch-kickstart2.html Kickstart Installations]* [http://www.centos.org/docs/5/html/5.2/Installation_Guide/ch-redhat-config-kickstart.html Kickstart Configurator]

=Performing Lab 2=My Toolkit (CLI Reference)==Comparison Chart == You will be learning to perform several different type of CENTOS Linux installs. As you proceed throughout this lab, you will be required to fill in the following table to be used for installation type comparison. You should try to fill out the section for the CENTOS install you performed in lab #1, and then continue with this lab.

{|width="100%" cellpadding="15"|- valign="top"|width="20%" |<u>Virtualization:</u>x<br>x|width="20%" |<u>Commands</u>[http://unixhelp.ed.ac.uk/CGI/man-cgi?gzip gzip, gunzip]<br>[http://unixhelp.ed.ac.uk/CGI/man-cgi?grep 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]|width="20%" |<u>Installation Guides</u>[http://wiki.centos.org/HowTos/KVM Installing &amp; Using KVM on CentOS ]<br>[http://www.dedoimedo.com/computers/kvmComplete the following table (and transfer into your lab2 log-intro.html Using KVM (tutorialbook notes)]<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>

{|border="1" width="40100%" cellpadding="5"|-! ||c6host||centos1||centos2||centos3|-|'''Installation Method'''||Installation Disc||Live Disc||Network Installation|{{Admon/tip|Online Linux Command ReviewNetwork Installation + Kickstart|-|'''Number of Packages Installed'''|| || || |||-|'''Updates Installed immediately after installation'''|| || || |||-|'''Software could be selected during installation'''|| || || |||-|'''Disk layout could be selected during installation'''|| || || |||-|The following tutorial will allow you to learn essential shell scripting skills. Login to your '''MatrixAny questions asked during installation?''' account, and issue the pathname to run the online tutorial in Matrix:<br><ul><li>Shell Scripting || || || |||- Part 2 |'''Total installation time''' (Logic & Math Expressionsafter installation questions):<br>|| || || |||-|'''Amount of disk space used'/home/murray.saul/scripting''|| || || |||-2|'''Any questions asked during first boot?'''</li><li>Shell Scripting || || || |||- Part 3 (Loops)<br>|'''Advantages of this type of installation'''/home/murray.saul/scripting|| || || |||-3|'''Disadvantages of this type of installation'''</li></ul>|| || || |||-}}|'''This type of installation is recommended for...'''|| || || ||

You will be learning {{Admon/tip|Performing this Lab off the Seneca network (eg. at home)|'''It is recommended to perform several different type this lab in one of CENTOS Linux installsSeneca 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. Lab2 already has an empty table for comparing various Linux installssenecac. You were required in lab1 on.ca URLs to point to another mirror server -- note that you may need to record your observation for your change the directory name as well as the server name. The installation of the '''centos1centos3''' installationvirtual machine <u>must</u> be done at Seneca.}}

As you proceed throughout this lab# Open a web-browser, and open the OPS235 Lab #2 WIKI. '''<br /><br />NOTE:''' You need to enter your "MySeneca" username and password to obtain a "wired" Internet connection (otherwise, you will not be required able to perform the "groupinstall" command in the next step). Remember to fill perform a "wired-connection" (logging in with your MySeneca username and password via a web-browser) every time you boot-up your host machine...<br /><br /># Install the virtualization software (virtualization, libvirt, virt-manager) using <code>yum install</code> and/or <code>yum groupinstall</code>. This will install::* kvm/qemu - the comparison chart for three of hypervisor and other hardware emulation systems.:* A system service named libvirtd that manages the VMs (.:* A graphical tool for managing virtual machines) and the virsh command-line tool.<ol> <li value="3">Start the virtualization service: <code>service libvirtd start</code></li> <li>The firewall configuration is altered by the addition of the virtualization software. Restart the firewall so that you will be installingthese changes become active: <code>service iptables restart</code></li></ol><ol> <li value="5">Start the graphical tool by selecting the menu options '''Applications'''>'''System Tools'''>'''Virtual Machine Manager''' or by typing the command <code>virt-manager</code>.</li></ol>

== Part Investigation 1: Installing from a Downloaded Image (Centos7 LIVE CD) =={| width="40%" alignLive Disc ="right" cellpadding="10"|- valign="top"|{{Admon/tip|Perform Downloads and Network installs at SenecaUsing an Image instead of a Live Disc|'''It is recommended to that you 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 installation from other locations (such as your home)Live DVD. 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 As a matter of the '''centos3''' virtual machine <u>must</u> be done at Seneca.}}|-|{{Admon/important|Removing and Recreating VMs|If interest (for some reason the user wants to remove a Virtual Machinefuture reference), they can right-click the VM, and select delete in the Virtual Machine Manager. It it is recommended possible to '''"delete install directly from the image ISO file" in the remove VM dialog box when removing and then recreating a VM'''. Note: If you fail used to properly remove the VM image file, it may affect the hard disk size for the new VM (iburn your Live DVD.e. use There are many Internet tutorials that show the old smaller size. Make certain individual how to remove perform that VM image file prior to recreating the VMtask.|'''}}|}==== Introduction ====

* '''Name:''' centos1* '''Boot media:''' CentOS Live DVD* '''Installation source:'''VM DetailsLive DVD* '''Memory:''' 768MB* '''Disk space:''' 10GB* '''CPUs:'''1

# '''Step 1 of 5:'''Select Enter the virtual machine (called '''Local install mediacentos1''' ) name and click select '''ForwardLocal install media'''.# '''Step 2 of 5:''' Select Insert the DVD containing the Centos Live Disc image. Wait a moment for the disc to be recognized, then select '''Use ISO ImageCDROM or DVD''', click as the install media. Set the ''OS type'' to '''BrowseLinux''' button, and then the '''Browse Local'Version'' button. Navigate to the location of the downloaded Centos7 LIVE CD image, select the image file and click '''OpenRed Hat Enterprise Linux 6'''. When finished, click Forward to proceed(the CentOS6 equivalent).# '''Step 3 of 5:''' Set the memory to '''2048 768 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'''. Click on<br> and checkmark the box labeled '''Allocate entire disk now'''Select managed or other existing storage# ''' and type the VM image file pathameStep 5 of 5:<br> '''/var/lib/libvirt/images/centos1Review the options that you have selected.img''' (make certain that Make a note of the pathname is correct) and then click storage location.'''If anything needs to be changed, use the 'Forward'Back'' button to proceed.</li><li>go back and edit it; otherwise, click '''Step 5 of 5:Finish''' Enter  {{Admon/important|Removing and Recreating VMs|If for some reason the user wants to remove a Virtual Machine, they can right-click the VM, and select delete in the virtual machine name: Virtual Machine Manager. It is recommended to '''centos1"delete the image file" in the remove VM dialog box when removing and then recreating a VM'''. Review Note: If you fail to properly remove the VM informationimage file, and click 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.|'''Finish'''.}} <br><br></liol> <livalue="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 hard-drive harddrive first.</li></ol> <ol> <livalue="9">Double-click Click '''Install to Hard Drive'''. The installation program, similar to the one used when installing CentOS in Lab 1, will appear. You basically perform will get a warning at one point during the same installation operations for this VM including for '''Date & Time''', '''Network & Hostname''', and '''Installation Destination'''. Make certain to use process that the '''hostname''': '''<u>centos1</u>''' as opposed disk "May contain data" or "may need to ''centos1'') for be re-initialized" -- this installation. (with is simply a few slight differences).</li><li>For '''Installation Destination''', select the destination option: '''I will configure partitioning''' and then click '''Done'''. Make certain warning that the '''Partition Scheme''' virtual disk is set to '''LVM''' completely blank, 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 it is installing, take a few minutes safe to record your observations (including slight differences proceed with centos1 install as opposed to centos1 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>< {{Admon/li><li>Power-off your Centos7 LIVE systemnote|Virtual Machine Screen Size|The virtual machine screen size will change resolution as it switches from text to graphics mode.</li><li>You should notice that Use the Centos7 boot VM menu appears. Either press '''ENTER''' option View>Resize to start or wait for it VM to start automatically.</li><li>Finish resize the final steps in window to show the setup process (like you did in lab1)entire VM display.</liIf this is larger than your screen size, use View><liScale Display>#You may want Always to turn off scale the image so it fits on your 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="1310">Enable SSH access to your virtual machine with these commands (semi-colon allows commands to be run in sequence):<br /> <b><code><span style="color:#3366CC;font-size:1During the installation process, when prompted for a storage device, first select '''Specialized Storage Devices''', and then select the '''Virtio Block Device''' option.2em;">service sshd start; chkconfig sshd on</span></code></b></li> <li>Find out When prompted for the IP address of your virtual machine hostname, enter '''centos1''', and when prompted for the name of your Ethernet network adaptor: <b><code><span style="color:#3366CC;fonttimezone, select '''Toronto -size:1.2em;">ifconfig</span></code></b> Eastern Time Ontario'''</li> <li>Enter When asked about storage, select '''Use All Space'''. '''Use the default values for all other fields.''' Notice that the following command on your virtual machine installer does not ask you what software should be installed; compare the installation time to create a firewall exception the amount of time it took to allow ssh traffic into do your Lab 2 installation. Record this information in the machine:'''table contained in Investigation 4'''.<br /li> <bli><code><span style="color:#3366CC;fontWhen the installation is complete, click on the '''reboot''' button at the bottom right-size:1hand corner of the screen.2em;">iptables -I INPUT -p tcp -s0/0 -d0/0 --dport 22 -j ACCEPT</spanli></codeol> </bol> </livalue="13"><li>If you are logged in as root, logout to your regular user accountStart the VM from its disk image.</li><li>Confirm that you This can ssh to your virtual be done graphically by selecting the Virual machine from name, and then clicking on the host (your main CentOS installation): <b><code><span style="color:#3366CC;font-size:1.2em;">ssh regularuserid@IPaddress</span></code></b> (where '''regularuseridOpen''' is your regular user login idbutton, and then click the '''IPaddressplay''' is button when the next screen appears (or by selecting Virtual Machine>Run from the virtual machine menu). You will get the '''IP_ADDRESS'Firstboot'' configuration questions during the boot process (asking you to create a user, set the date and time, and ignore the kdump out-of your '''centos1''' VM!-memory warning).</li><li>Make certain to '''disable SELinux for centos1''' that the VM has a network interface connection (refer to lab1i.e. look at network applet on the top panel). Create a user with the same name as your Matrix account.</li> <li>Adjust your screen-saver settings and run a '''yum update''' on your centos1 VM before proceeding to ''Part 2''Login using the new user account.</li></ol>

{{Admon/tip|Authenticate to the network|The rest of this lab uses network access.'''Answer Be sure to authenticate to the Investigation 1 observations / questions in network using your lab log book.browser before proceeding'''.}}

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

:: '''==== VM Name (and hostname):''' centos2:: '''Boot media:''' Network installation:: '''Installation source URL:''' http://belmont.senecac.on.ca/centos/7/os/x86_64/:: '''VM Image Pathname:''' /var/lib/libvirt/images/centos2.img:: '''Memory:''' 2048MB:: '''Disk space:''' 20GB:: '''CPUs:''' 1details ====

==== Steps ====# Create the VM (called '''centos2''') as you did with the ''centos1'' virtual machine, except for select network installation using the installation source url displayed above.# Observe the boot process. How is it different from booting from an optical disc (DVD)?# Start the installation process (make certain to use information in the following differences:<br><br><ol type="a"><li>Select ''VM Details'' section above).# When you get to the disk partitioning step, select '''Network InstallationUse All Space''' using and enable the installation source URL displayed abovecheckbox labelled '''Review and modify partition layout'''.</li><li>When customizing your partitionsIf an dialog box displays a permissions problem, do then click yes to proceed. On the same operation that you did in centos1next screen, but after automatically creating change the partitions, reduce logical volumes as follows:#* Reduce the size of the root LVM partition LV to '''8000 MB''' and add an LVM partition .#* '''Add a <u>logical volume</u> with a size of '''2000 MB''' (mount point: '''and a mountpoint of /home''', (you can name: '''home'''it whatever you want, and make certain root and /home partitions have use '''ext4''' as the file -systemtype).</li><li>Don't forget to install the GNOME desktop here as you will need a GUI for Centos2<br><br></li></ol># Complete the installation. Login to your regular user account, and perform a yum update for On the centos2 VM (reboot if required). Make certain to adjust your software selection screen-saver settings if desired.# Repeat the steps as you did to '''start the SSH service''', '''set iptables to accept connections via ssh''', select '''test connections between centos2 and centos1Desktop''', and '''disable SELinux''' (refer to lab1).# Complete the installation. Record the time taken to install, and compare this to the time taken by the previous installations. Record your findings this information in the Installation Comparison chart '''table contained in lab2 logbookInvestigation 4'''.

== Part Investigation 3: Installing from a the 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 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:''' 1details ====

# Observe the installation. How is it different from booting from a downloaded imagean optical disc?# 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!.

{| 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 '''centos1''' machine, and open a shell terminal.# Enter these admin commands into your '''centos1''' machine and note Answer the result::: <b><code><span style="color:#3366CC;font-size:1.2em;">virsh list</span><Investigation 3 observations /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>{| 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 questions 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 windowlab log book.</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>

'''Answer all observations {{Admon/ questions in important|Check that your lab log bookgraphical VMs are connected to Network|It is recommended when starting a graphical VM, check the network icon to see if the system is connected.'''If it is NOT connected, select auto eth.}}

'''Answer the Investigation observations {{Admon/ questions in 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 time prior to performing an update. Shutting down your computer while performing an update may cause your lab log book.'''computer not to boot! You have been warned!!!}}

==Part 1: Automating Routine Tasks (Shell Scripting)=={|width="40%" align="right" cellpadding="10"|- valign="top"|{{Admon/tip|Bash Shell Scripting Tips:|<br><ul><li>'''Data InputInvestigation 5:'''<br><br>A shell script can obtain data Managing Virtual Machines 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, for example: '''read -p "Enter your name: " userName'''.<br><br></li><li>'''Mathematical Expressions:'''<br><br>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><u>'''Examples'''</u><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><li>'''Loops (iteration):'''<br><br>Loops and logic are a very important elements of shell scripting (not to mention programming as well). 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). 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. Command options or redirection to /'''dev/null''' can be used to just test if command runs, but not display stdout or stderr. Conditional statements "and" (&amp;&amp;) / "or" (&#124;&#124;) can also be used when testing multiple conditions.<br><br>'''<u>Examples (try in a shell script)</u>'''<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''<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>}}|}Line ==

You will continue our use of Bash Shell scripting by first creating a Bash Shell script that will allow {{Admon/note|Manage virtual machines from the Linux sysadmin host|The commands used to select their created VMs for backup to root's home directory. Afterwards you will download, view manage virtual machines must be executed on the host (your disk pack) and run not inside a couple Bash Shell scripts that use the virsh command to start and stop your virtual machinesmachine.}}

If you require <u># Start the ''centos1'' virtual machine, and stop the ''centos2''and 'additional practice'centos3''</u> in creating shell scripts using logicvirtual machines.# Switch to the c6host machine, loops and mathematical operations, run the open a shell terminal.# Enter these commands in into your c6host machine and note the result:#* <code>'''Matrixvirsh list''' account: <ul/code>#* <licode>'''/home/murray.saul/scriptingvirsh list --2all'''</licode>#* <licode>'''/home/murray.saul/scriptingvirsh list --3inactive'''</licode># Now, shut-down your centos1 VM normally, and close the centos1 VM window.# Switch to your terminal and issue the command: <code>'''virsh start centos1'''</ulcode># Using the appropriate command check to see if your centos1 VM is now running.# 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?

Perform {{Admon/note|Virtual Machine Does not Shutdown from Command|If the following steps 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 your centos1 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:!|}}

# 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;">backupVM.bash</span><'''Answer the Investigation 5 observations /code></b> questions in /root's home directory.# Enter the following text content into your text-editing session:<code style="color:#3366CC;font-family:courier;font-size:lab log book.9em;margin-left:20px;"><br>&#35;!/bin/bash'''

&#35; backupVM.bash{{Admon/important|Backing up VMs|There are two general processes in order to back up your images:<ol><brli>&#35; Purpose: Creates system info report'''Compressing your images''' (also recommended to backup up to external storage USB Key) using the '''gzip''' command.<br/li>&#35;<brli>&#35; USAGE: '''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).</report.bashli><br/ol>&#35;<br/>&#35; Author: *** INSERT YOUR NAME ***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/>&#35; Date: *** CURRENT DATE ***Failure to take the time to make and confirm backups can result in loss of lab work for the student!|}}

if [ $PWD != "{{Admon/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="4">Save your editing session, but remain in the text editor.</li><li>This shell script important|Backing up VMs|It is designed particularly for essential to back up 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 at the option end of specifying which VMs to be backed-up. Add each lab, so you can easily restore them if something goes wrong in the following code</li></ol><br><code style="color:#3366CC;font-family:courier;font-size:next lab.9em;">}}

read -p "Backup all VMs? (y{{Admon/tip|n):" answer # prompt if all VMs to Shutting Down the Host while Virtual Machines are Running|If you shut down your host system while virtual machines are running, they will be backed-upsuspended, and will resume the next time you boot your host system.}}

if [ "$answer" = "y" ] # Backup all VMs if answer is yes<br>then<br>&nbsp;for num '''Answer the Investigation 6 observations / questions in 1 2 3 # Determinant loop for 3 arguments: 1, 2, and 3<br>&nbsp;do<br>&nbsp;&nbsp;echo "Backing up VM #$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): " 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.img > /root/centos$numanswer.img.backup.gz<br><br>&nbsp;echo "VM #$numanswer BACKUP DONE":<br>else<br>&nbsp;echo "Invalid Selection..your lab log book. Aborting program"<br>&nbsp;exit 2<br>fi'''

<ol><li value="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 the Investigation 7 observations / questions in your lab log book.'''

= LAB 2 SIGN-OFF (SHOW INSTRUCTOR) Completing the Lab ={{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 evidence for each of the following these items on your screen, then ask your instructor to review them and sign off on the screenlab's completion:'''

<ol><li><span style="color:green;font-size:1.5em;">&#x2713;</span> '''<u>All</u> VMs''':<blockquote><ul><li>Working Three working virtual machines '''created''' and '''running'''</li><li>'''.# Disk layout''' and '''size''' correct on all virtual machines</li><li> Proof # Use virsh to list the status of '''yum updates'''</li><li>'''all vms.# Four kickstart files.# All virtual machines fully updated.# All virtual machines backed-up''' (eg. to a usb stick and/or home directory)</li></ul></blockquote></li><li><span style="color:green;font-size:1.5em;">&#x2713;</span>'''centos1''' machine:<blockquote><ul><li>'''Correct VM image filenames''' contained Installation comparison table filled 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 # Lab Logbook (command: '''iptables -L'''lab2)</li></ul></blockquote></li><li><span style="color:green;fontnotes filled-size:1in.5em;">&#x2713;</span> Lab2 logbook notes and '''Installation Comparison chart''' completed</li></ol>

== Practice For Preparing for Quizzes, Tests, Midterm &amp; Final Exam ==

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

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