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=INVESTIGATION 2: COMMON POST-INSTALL TASKS=

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{{Admon/caution|Allow Time to Perform Yum Updates|Allow sufficient time in order to perform updates prior to the end of the lab. Since you will be updating ALL of your VMs, allow 15-20 "lead-time" to start your updates and to backup your VMs prior to the end of the lab. '''NEVER force a shut-down of your VM while updates are running, since this will ruin your VM''', and you will have to restore from a backup, or redo your labs for that VM!}}

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It is important as a Linux System Administrator to update software on your Linux system periodically. Performing periodic updates will fix software bugs and inefficiencies as well as apply security patches in order to better secure your Linux server.

This will download and install all of the packages that have been updated since the installation DVD image was created. If you complete this command at Seneca, it should run quite fast as Seneca College hosts a CentOS Repository mirror (a copy of all of the current CentOS packages, on a local web server). You will be reminded at the end of each of the remaining labs to perform software updates on ALL of your VMs.

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|colspan="2"|{{Admon/important|Backing up VMs|There are two general processes in order to back up your images:<ol><li>'''Compressing your images''' (also recommended to backup up to external storage USB Key) using the '''gzip''' command.</li><li>'''Backup the VM xml configuration file''' (preferably to USB key) using '''virsh''' shell command to add VM to virtual machine manager list (in the event that the HOST machine is "wiped" and re-installed, but VM images and xml configuration files have been backed up external storage).</li></ol><br />Taking the time to backup the image of the Operating System's file system allows the user to return to a '''"restoration point"''' using the '''gunzip''' command in case something bad occurs to the OS during a lab.<br />Failure to take the time to make and confirm backups can result in loss of lab work for the student!|}}

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'''Perform the following steps:'''

# 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.qcow2.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>What happened in the virtual manager window? To remove a VM entry in the Virtual Manager window, simply issue the command: '''virsh undefine vm_name''' (without the '''.xml''' file extension)</li><li> Launch the VM to see if it boots-up</li><li>Can you log into this VM? Perhaps your instructor will give you a clue in week #7... >;p<br><br></li></ol>

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<li value="22">For the remainder of these labs, it is assumed that you will backup <u>'''both'''</u> the images and xml configuration files for <u>'''all'''</u> Virtual machines, when asked to backup your virtual machines. It is also highly recommended to backup these files to an external storage device (eg. USB key) in case the host machine gets "wiped" and you need to rebuild your HOST machine and then restore your Virtual Machines...</li>