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OPS235 Lab 2 - CentOS7 - SSD

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=== Part 3: ~~Backing Up Virtual Machines ==={| width="40%" align="right" cellpadding="10"|- valign="top"|colspan="2"|{{Admon/important|Backing up~~ Manipulating VMs|There are two general processes in order to back up your images:<ol><li>'''Compressing your images''' (also recommended to backup up to external storage USB Key) using the '''gzip''' command.</li><li>'''Backup the VM xml configuration file''' (preferably to USB key) using '''virsh''' shell command to add VM to virtual machine manager list (in the event that the HOST machine is "wiped" and re-installed, but VM images and xml configuration files have been backed up external storage).</li></ol> 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. Failure to take the time to make and confirm backups can result in loss of lab work for the student!|}}|}~~# Shut down all of the virtual machines.# Change to the directory <code>/var/lib/libvirt/images/</code>. Note the size of the files in this directory. What do these files contain?~~# Make a compressed backup of the '''centos3.qcow2''' file to your home directory with this command: <code>gzip < centos3.qcow2 > ~YourUserId/centos3.qcow2.backup.gz</code> (Note: Make certain to use the redirection signs "<" and ">" properly in the command!)# Compare the size of the compressed and original files (hint: use '''ls -lh'''). If file is very large (like 15GB), you didn't compress it and you need to remove that file and perform the previous step until you get it right!~~# Start the '''''centos3''''' VM.# '''Make certain that you are in your VM and not in your main system!'''~~ ~~# Wreck only your centos3 system! Try this command inside the centos3 virtual machine:<code>rm -rf /*</code> (ignore error messages).# Shut down the centos3 VM. If you tried to start the centos3 VM, it would not boot since all system files have been removed!~~# Restore the original image from the backup in your home directory by typing this command: <code>gunzip < ~YourUserId/centos3.qcow2.backup.gz > centos3.qcow2'''</code>~~# 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: <code>virsh dumpxml centos3 > centos3.xml</code># Examine the file <code>centos3.xml</code>. What does it contain? What format is it in? # 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><code>wget http://cs.senecac.on.ca/~murray.saul/ops235/practical1.qcow2.gz</code></li><li><code>wget https://scs.senecac.on.ca/~murray.saul/ops235/practical1.xml</code> </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: <code>virsh define practical1.xml</code></li><li>What happened in the virtual manager window? To remove a VM entry in the Virtual Manager window, simply issue the command: '''virsh undefine vm_name''' (without the '''.xml''' file extension)</li><li> Launch the VM to see if it boots-up</li><li>Can you log into this VM? Perhaps your instructor will give you a clue in week #7... >;p </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.}}|}~~<ol>~~ <li value="22">For the remainder of these labs, it is assumed that you will backup '''both''' the images and xml configuration files for '''all''' Virtual machines, when asked to backup your virtual machines. It is also highly recommended to backup these files to an external storage device (eg. USB key) in case the host machine gets "wiped" and you need to rebuild your HOST machine and then restore your Virtual Machines...</li>~~<li>Answer this question in your log book:</li></ol>::* In order to fully back up a virtual machine, what information should be saved in addition to the virtual machine image?~~<ol><li value="24">A previous OPS235 student graciously created a shell script that you can download and run to check to see how you performed this lab (to see if you are on the right track). Simply issue the command: <code>wget http://matrix.senecac.on.ca/~murray.saul/ops235/lab2check2.bash</code> and run on your '''c7host machine'''. '''If the shell script indicates any major errors, please inform your OPS235 instructor or lab assistant to advise what to do'''. </li></ol> ~~===Part 4: Automating Routine Tasks (~~via Shell ~~Scripting)~~Scripts===

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<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 <code>wget</code> command to download, study, and run the following shell scripts on-line:<blockquote><code>https://scs.senecac.on.ca/~murray.saul/vm-start-text.bash https://scs.senecac.on.ca/~murray.saul/vm-stop-text.bash</code> <code>https://scs.senecac.on.ca/~murray.saul/vm-start.bash https://scs.senecac.on.ca/~murray.saul/vm-stop.bash</code></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>

=== Part 4: Backing Up Virtual Machines ==={| width="40%" align="right" cellpadding="10"|- valign="top"|colspan="2"|{{Admon/important|Backing up VMs|There are two general processes in order to back up your images:<ol><li>'''Compressing your images''' (also recommended to backup up to external storage USB Key) using the '''gzip''' command.</li><li>'''Backup the VM xml configuration file''' (preferably to USB key) using '''virsh''' shell command to add VM to virtual machine manager list (in the event that the HOST machine is "wiped" and re-installed, but VM images and xml configuration files have been backed up external storage).</li></ol> 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. Failure to take the time to make and confirm backups can result in loss of lab work for the student!|}}|}# Shut down all of the virtual machines.# Change to the directory <code>/var/lib/libvirt/images/</code>. Note the size of the files in this directory. What do these files contain?# Make a compressed backup of the '''centos3.qcow2''' file to your home directory with this command: <code>gzip < centos3.qcow2 > ~YourUserId/centos3.qcow2.backup.gz</code> (Note: Make certain to use the redirection signs "<" and ">" properly in the command!)# Compare the size of the compressed and original files (hint: use '''ls -lh'''). If file is very large (like 15GB), you didn't compress it and you need to remove that file and perform the previous step until you get it right!# Start the '''''centos3''''' VM.# '''Make certain that you are in your VM and not in your main system!''' # Wreck only your centos3 system! Try this command inside the centos3 virtual machine:<code>rm -rf /*</code> (ignore error messages).# Shut down the centos3 VM. If you tried to start the centos3 VM, it would not boot since all system files have been removed!# Restore the original image from the backup in your home directory by typing this command: <code>gunzip < ~YourUserId/centos3.qcow2.backup.gz > centos3.qcow2'''</code># 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: <code>virsh dumpxml centos3 > centos3.xml</code># Examine the file <code>centos3.xml</code>. What does it contain? What format is it in? # 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><code>wget http://cs.senecac.on.ca/~murray.saul/ops235/practical1.qcow2.gz</code></li><li><code>wget https://scs.senecac.on.ca/~murray.saul/ops235/practical1.xml</code> </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: <code>virsh define practical1.xml</code></li><li>What happened in the virtual manager window? To remove a VM entry in the Virtual Manager window, simply issue the command: '''virsh undefine vm_name''' (without the '''.xml''' file extension)</li><li> Launch the VM to see if it boots-up</li><li>Can you log into this VM? Perhaps your instructor will give you a clue in week #7... >;p </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.}}|}<ol> <li value="22">For the remainder of these labs, it is assumed that you will backup '''both''' the images and xml configuration files for '''all''' Virtual machines, when asked to backup your virtual machines. It is also highly recommended to backup these files to an external storage device (eg. USB key) in case the host machine gets "wiped" and you need to rebuild your HOST machine and then restore your Virtual Machines...</li><li>Answer ~~all~~ this question in your log book:</li></ol>::* In order to fully back up a virtual machine, what information should be saved in addition to the virtual machine image?<ol><li value="24">A previous OPS235 student graciously created a shell script that you can download and run to check to see how you performed this lab (to see if you are on the right track). Simply issue the command: <code>wget http://matrix.senecac.on.ca/~murray.saul/ops235/lab2check2.bash</code> and run on your '''c7host machine'''. '''If the shell script indicates any major errors, please inform your OPS235 instructor or lab assistant to advise what to do'''. </li></ol> '''Answer INVESTIGATION 2 observations / questions in your lab log book.'''

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