Open main menu

CDOT Wiki β

OPS235 Lab 3 - Fedora17

Revision as of 14:35, 21 January 2010 by Cheping (talk | contribs) (Investigation 6: How do I backup a virtual machine?)
Stop (medium size).png
This lab is under construction.
Please do not print or do this lab until it is finalized.

Using Virtual Machines

Objectives

  • Understand Virtualization
  • Use KVM virtualization on Fedora
  • Use a variety of installation methods
    • Live Image Installation
    • Network Installation
    • Kickstart Installation

Reference Material

Virtualization

Installation Methods

Required Materials

  • Removable disk pack with Fedora installed (see Lab 2).
  • Fedora Live CD.
Performing this Lab off the Seneca network
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 Fedora mirror server -- note that you may need to change the directory name as well as the server name.

Introduction

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 flexibility. Some common uses of virtualization include:

  • Software testing -- Using multiple operating systems simultaneously on a single computer for testing and experimentation.
  • Network simulation -- Testing network services, protocols, 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 machines is still protected.
  • Server consolidation -- Reducing the number of physical servers in a network by moving physical machines to virtual machines. This 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 migrate virtual machines between different 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.

In this lab, you will create three virtual machines. This also gives you an opportunity to experiment with different ways of installing Fedora. Later in this course you will install another operating system distribution in a virtual machines.

You have already used a Fedora live disc and an installation disc. In both cases, the boot media (which you used to load the installation software) and the installation source (where the software that got installed came from) were the same: they CD/DVD provided both. However, the Fedora (and most other Linux distributions) permits you to use any combination of boot media and installation media:

  • Boot Media
    • CD or DVD
    • Hard disk
    • USB flash drive
    • Network boot
  • Installation source
    • CD or DVD
    • Hard disk
    • USB flash drive
    • Network HTTP or NFS software repository

Instructions

Preparation

Update your Fedora Installation
It's a good idea to ensure that your Fedora installation is fully updated before proceeding. You can update your system with the graphical tool located on the menu at >System>Administration>Software Update (or type the command gpk-update-view), or by typing either of these commands: pkcon update or yum update
  1. Install the Fedora virtualization software: yum groupinstall "Virtualization" or pkcon install @virtualization The virtualization software installed is in three parts:
    1. A system service named libvirtd that manages the VMs.
    2. Tools to manage virtualization, including the virt-manager graphical tool and the virsh command-line tool.
    3. The actual virtual machines themselves.
  2. Start the virtualization service: service libvirtd start
  3. The firewall configuration is altered by the addition of the virtualization software. Restart the firewall so that these changes become active: service iptables restart
  4. Start the graphical tool by selecting the menu option Applications>System Tools>Virtual Machine Manager or by typing the command virt-manager

Investigation 1: Installing from a Live Disc

Introduction

In this investigation, you will install Fedora from your live disc, and observe the differences between this type of installation and the DVD installation previously performed.

VM Details

  • Name: fedora1
  • Boot media: Fedora Live CD
  • Installation source: Fedora Live CD
  • Memory: 512MB
  • Disk space: 10GB
  • CPUs: 1

Steps

  1. In the Virtual Machine Manger, click on the icon to Create a Virtual Machine in the upper-left corner:
     
  2. A window will appear with the title New VM. There are five steps to be completed; click Forward after each step:
  3. Step 1 of 5: Enter the virtual machine name and select Local install media.
     
  4. Step 2 of 5: Insert the CDROM or DVD containing the Fedora Live Disc image. Wait a moment for the disc to be recognized, then select it as the install media. Set the OS type to Linux and the Version to Fedora 12.
     
  5. Step 3 of 5: Set the memory to 512 MB and the number of CPUs to 1.
     
  6. 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 Allocate entire disk now.
     
  7. Step 5 of 5: Review the options that you have selected. Make a note of the storage location. If anything needs to be changed, use the Back button to go back and edit it; otherwise, click Finish.
     
  8. The virtual machine will now start. You will see a window which displays the virtual video card from the VM. The video It's important to note that the VM can (and often will) run even when this display is not present. 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.
  9. Login to the VM and double-click on the Install to Hard Drive icon. The installation program, similar to the one used when installing Fedora in Lab 2, will appear. You will get a warning at one point during the installation process that the disk "may need to be re-initialized" -- this is simply a warning that the virtual disk is completely blank, and it is safe to select Re-initialize drive.
  10. During the installation process, when prompted for the hostname, enter "fedora1", when prompted for the timezone, select America/Toronto, and when asked about storage, select Use Entire Disk. Use the default values for all other fields. Notice that the installer does not ask you what software should be installed; compare the installation time to the amount of time it took to do your Lab 2 installation.
  11. When the installation is complete, select the menu option System>Shutdown to stop the Live Disc.
  12. Start the VM from its disk image by selecting Virtual Machine>Run from the virtual machine menu. You will get the Firstboot configuration questions during the boot process (asking you to create a user, set the date and time, and optionally send the hardware profile to the Fedora Project). Create a user with the same name as your Matrix account.
  13. Login using the new user account.
  14. Enable SSH access to your virtual machine with these commands: service sshd start; chkconfig sshd on
  15. Find out the IP address of your virtual machine: ifconfig eth0
  16. Confirm that you can ssh to your virtual machine from the host (your main Fedora installation): ssh IPaddress

Investigation 2: Installing from the Network

Authenticate to the network
The rest of this lab uses network access. Be sure to authenticate to the network using your browser before proceeding.

Introduction

It is possible to install Fedora entirely from the network. In this investigation, you will install Fedora from a webserver on Seneca's LAN.

VM details

Steps

  1. Create the VM as you did with the fedora1 virtual machine, except:
  2. Observe the boot process. How is it different from booting from an optical disc (CD/DVD)?
  3. Start the installation process. When you get to the disk partitioning step, enable the checkbox labelled Review and modify partition layout. On the next screen, change the logical volumes as follows:
    • Reduce the size of the root LV to 4000 MB.
    • Add a logical volume with a size of 1000 MB and a mountpoint of /home (you can name it whatever you want).
  4. On the software selection screen, uncheck the box for Office and Productivity (as well as the other software choices).
  5. On the same screen, select the "Fedora 12 - x86_64" and the "Fedora 12 - x86_64 - Updates". DO NOT enable the "Test Updates" repository.
  6. Complete the installation. Record the time taken to install, and compare this to the time taken by the previous installations.

Investigation 3: Installing from the Network using Kickstart

Introduction

When Fedora 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.

In this investigation, a kickstart file is provided for you. You can also create or modify a kickstart file using a regular text editor or a graphical tool.

VM details

Steps

  1. Create the VM as you did with the fedora2 virtual machine, specifying a network install as before, except:
  2. Observe the installation. How is it different from booting from an optical disc (CD/DVD)?
  3. Complete the installation. Record the time taken to install, and compare this to the time taken by the previous installations.
  4. What happens when the installation is finished?
  5. Take a look at the kickstart file (using the URL you entered) to determine the root password as well as the name and password for the first user account.
  6. Boot the virtual machine and log in. Compare the experience to booting the other virtual machines.

Investigation 4: Updating the VMs

  1. In each VM, run this command: yum update
  2. Record the answers to these questions in your log book:
    • How long did it take to run on each VM? How many packages were updated?
    • Why does it take longer in some VMs than others?


Investigation 5: Managing Virtual Machines from the Command Line

  1. Start the fedora1 virtual machine, and stop the fedora2 and fedora3 virtual machines.
  2. Enter these commands and note the result:
    • virsh list
    • virsh list --all
    • virsh list --inactive
  3. Start the fedora3 virtual machine from the command line: virsh start fedora3
  4. Repeat the commands from step 2 and notice any changes.
  5. Stop the fedora3 virtual machine: virsh shutdown fedora3
  6. Confirm that fedora3 has been shut down.
  7. Execute this command: virsh dumpxml fedora3 >fedora3.xml
  8. Examine the file fedora3.xml. What does it contain? What format is it in?
  9. Edit the file fedora3.xml, making the following changes:
    • Change the name to fedora3a
    • 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.
  10. Issue this command: virsh define fedora3.xml
  11. Issue the command virsh list --all and record any changes.
  12. Issue the command: virsh undefine fedora3a
  13. List all of the virtual machines again, and note any changes.

Investigation 6: How do I backup a virtual machine?

  1. Shut down all of the virtual machines.
  2. Change to the directory /var/lib/libvirt/images/. Note the size of the files in this directory. What do these files contain?
  3. Make a compressed backup of the fedora3.img file with this command: gzip <fedora3.img >fedora3.img.backup.gz
  4. Compare the size of the compressed and original files.
  5. Start the fedora3 VM.
  6. Wreck it! Try this command inside the fedora3 virtual machine (DO NOT do this on your main Fedora system!): rm -rf /
  7. Shut down the VM.
  8. Restore the original image from backup: gunzip <fedora3.img.backup.gz >fedora3.img
  9. Restart the VM. Is it working normally?
  10. Create compressed backups of your other virtual machines.
  11. Answer this question in your log book:
    • In order to fully back up a virtual machine, what information should be saved in addition to the virtual machine image?
  12. Write the answer to the Investigation 6 question in your lab book.

Investigation 7: Kickstart Files

When you perform a non-Kickstart installation, the installation program creates a Kickstart file in the /root directory for reference.

  1. Obtain the kickstart files for all four of your installations (your disk pack, plus the fedora1, fedora2, and fedora3 virtual machines).
  2. Compare these files. What are the differences? Similarities? (Tip: you may want to use tools such as sdiff to help with the comparison).
  3. How could you use the kickstart file produced by the installation program to perform additional, identical installations?

Preparing for the Quizzes

  1. What is the name of the Fedora installation program?
  2. What are the advantages and disadvantages of each type of installation?
  3. Which type of installation works best for confirming compatibility with hardware before installation? Why?
  4. Which type of installation works best for installing large numbers of computers? Why?
  5. What factors affect installation time?
  6. How can you reduce the number of software updates required immediately after installation?
  7. Why would you enable additional repositories during installation?
  8. Where does the file /root/anaconda-ks.cfg contain, and how is it created?
  9. How do you start and stop virtual machines?
  10. How do you SSH into your virtual machines?
  11. What is the purpose of and relationship between these pieces of software?
    • libvirt
    • libvirtd
    • virsh
    • virt-manager
    • virt-install
    • vncviewer
    • kvm