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OPS235 Lab 5

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→‎Part 2: Adding Additional Virtual Hard Drives

~~[[Category:OPS235]]~~

=LAB PREPARATION=

{| width="40%" align="right" cellpadding="10"

[[Image:crontab.png|thumb|right|175px|Linux system administrators need to schedule Linux shell scripts and commands (via '''crontab''') to automatically run in order to be more productive.]]

|}

===Purpose / Objectives of Lab 5===

[http://man7.org/linux/man-pages/man8/pvdisplay.8.html pvdisplay]

[http://man7.org/linux/man-pages/man8/lvdisplay.8.html lvdisplay]

[http://manpages.ubuntu.com/manpages/trusty/man8/ssm.8.html ssm]

|style="padding-left:20px;" |LVM Management

~~[http://manpages.ubuntu.com/manpages/trusty/man8/ssm.8.html ssm] ~~

[http://man7.org/linux/man-pages/man8/lvextend.8.html lvextend]

[http://man7.org/linux/man-pages/man8/lvcreate.8.html lvcreate]

[http://code.tutsplus.com/tutorials/scheduling-tasks-with-cron-jobs--net-8800 Using crontab]

|}

= INVESTIGATION 1: MONITORING HARD DISK SPACE =

#Make certain you are logged in as '''root'''.

#Change to the '''/root/bin''' directory.

#Download the following shell script by issuing the following command: <code>wget https://~~scs.senecac~~ict.onsenecacollege.ca/~~~murray.saul~~ops235/labs/monitor-disk-space.bash</code>

#Try to understand what this Bash Shell script does (refer to man pages for the '''awk''' command), and then run the script as root.

#Give execute permissions and run this shell script. This script is supposed to notify the root user by email if there are any potential partition size issues.

'''Answer INVESTIGATION 1 observations / questions in your lab log book.'''

=INVESTIGATION 2: MANAGING HARD DISK SPACE USING LVM=

# You can create a partition by using the fdisk command. Issue the following command: <code>fdisk /dev/vda</code> (or fdisk /dev/sda if there is no /dev/vda).

#At the '''fdisk''' prompt, issue the command: <code>p</code>. What does this do?

#Now issue the commands <code>n</code> (new partition), <code>p</code> (primary partition), <code>3</code> (i.e. next available partition number). When prompted for initial block, press '''enter''' to accept the default beginning block size, and type: <code>+3G</code> at ending block (create ~~2GB for~~ a 3GB partition) and press '''enter'''.

#At the fdisk prompt, issue the command <code>p</code> to review the partition information.

#Enter the command <code>w</code> to save partition table and exit (ignore WARNING message).

<li>Re-issue the '''ssm''' command. Do you see a new /dev/vda3 partition under Physical Volumes?</li>

<li>To add the newly created partition, you need to add it into LVM to be used. Issue the following command to add the partition into LVM: <code>pvcreate /dev/vda3</code> (or ''pvcreate /dev/sda3'' ) (enter '''y''' to proceed - ignore warning)</li>

</ol>{{Admon/important|Check your VG name|Run vgs to determine your Volume Group name. If it is just centos or cl, replace centos_centos2 with centos or cl for the rest of the following commands in this lab.}}<ol><livalue="17">Issue the following command to add your new-created and formatted partition called /dev/vda3 to your volume group: <code>vgextend centos_centos2 /dev/vda3</code></li>

<li>Create a new logical volume by issuing the following command: <code>lvcreate -L 2G -n archive centos_centos2</code></li>

<li>Format your newly-created partition by issuing the command: <code>mkfs -t ext4 /dev/centos_centos2/archive</code></li>

<li>Issue the '''ssm list''' command to view the new physical volume and logical volume information.</li>

</ol>{{Admon/important|Pay attention to syntax|Note that the prefixed "+" or "-" in lvextend and lvreduce will add or subtract from the current size. Omitting these prefixes will set the LV size to what you specified.}}<ol><livalue="21">Reduce the file-size by issuing the command: <code>lvreduce -r -L -0.5G centos_centos2/archive</code></li>

<li>Issue the '''ssm list''' command to verify.</li>

<li>Increase the file-size by issuing the command: <code>lvextend -r -L +1G centos_centos2/archive</code></li>

<li>Issue the '''ssm list''' command to verify.</li>

</ol>

[[Image:Add_virtual_disk.png|thumb|right|400px|You can add virtual hard disks for a VM by changing to the Details section for the VM (as opposed to console), click Add Hardware, fill information in the Add New Virtual Hardware dialog box and clicking Finish.]]

|}

===Part 2: Adding Additional Virtual Hard Drives===

<li value="3">Record the size of the volume group and the amount of free space</li>

<li>At the top of your KVM window for '''centos2''', click the '''view''' menu and change view from '''Console''' to '''Details'''''' .</li>

<li>At the bottom left-hand corner, click '''Add Hardware''' and add a new storage device of '''2GBs''', make sure the '''Bus type''' is selected ~~as:~~ '''~~VirtIO~~using the same type as your first drive that's already there''' ~~disk~~. If your first drive is SATA, IDE, or VirtIO, select that.</li>

<li>Click the '''VM''' menu again, and return to the '''console''' view to access your centos2 VM display.</li>

<li>Issue the command: <code>ls /dev/vd*</code>, what has changed?</li>

<li>Use '''fdisk''' (''refer to how to use in Part 1'') to create a new single '''primary''' partition for '''/dev/vdb''' that fills the ''entire'' disk, save partition table (accepting ~~defaults~~ default prompts would workand '''type w to write your changes'''!), restart your '''centos2''' VM ~~and then~~ .<li> Format your new ''vdb1'~~format~~'~~'' that~~ partition ~~for~~ with file type: '''ext4'''.</li> <li>Now we'll make the new device a '''physical volume''', add it to the '''volume group'''by issuing the following commands: <code>pvcreate /dev/vdb1</code> (enter '''y''' to proceed - ignore warning) <code>vgextend centos_centos2 /dev/vdb1</code> '''NOTE:''' If you experience an error message, issue the '''ssm list''' command, and check the '''volume group name''' under the '''"pool"''' section. If the volume group name is different than '''centos_centos2''', then use that volume group name for all remaining commands that use "centos_centos2" </li>

<li>Re-issue the '''ssm list''' command to see if there is any change.</li>

<li>Issue the following command to extend the logical volume for the home file-system: <code>lvextend -r centos_centos2/home --size +2G</code></li>

<li>Record the size of the volume group and the amount of free space. What has changed and what caused those changes?</li>

<li>Issue the '''ssm list''' command. Note that your home file-system is now 2GB bigger, and you have not even rebooted your machine since you used fdisk to create a partition!</li>

<ol><li value="8">View the contents of the file-system table '''/etc/fstab''' by issuing the following command: <code>cat /etc/fstab</code></li>

~~<li>Note the line that automatically mounts a file-system (''/dev/sda3'', type ''ext4'') to '''/archive'''. This was automatically performed for you via the '''system-config-lvm''' utility.</li>~~<li>View and record the fields for the '''/archive''' mount in your lab logbook, and then issue the following command to reconnect or mount '''/archive''': <code>mount   -t ext4   /dev/centos_centos2/archive   /archive</code></li><li>Use the ls command to view the contents of the /archive directory. What do you see?</li><li>Unmount the /archive directory by issuing the following command: <code>umount /archive</code></li><li>Issue the following command to add an entry to automatically mount the /archive directory upon bootup: <code>echo "/dev/centos_centos2/archive /archive ext4 defaults 1 2" >> /etc/fstab</code>~~ (although we don't need to do this, since it was already done).~~</li>

<li>'''Reboot''' your centos2 VM so see if the /archive directory is automatically mounted. '''Note:''' You could have also issued the command: '''mount -a''' to automatically mount the file-systems contained in the '''/etc/fstab''' file without booting the VM (good for testing before trying a reboot). </li>

</ol>

'''Answer the INVESTIGATION 2 observations / questions in your lab log book.'''

= LAB 5 SIGN-OFF (SHOW INSTRUCTOR) =

===Exclusively for Summer 2020 term, submissions are accepted only online!===

Follow the submission instructions for lab 5 on Blackboard.

{{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.}}

# Switch to your '''c7host''' machine.

# Open a shell terminal, '''su -''' into root, and change to the '''/root/bin''' directory., open a shell terminal

# Issue the Linux command: <code>wget ~~http~~https://~~matrix~~ict.~~senecac.on~~senecacollege.ca/~~~murray.saul~~ops235/~~ops235~~labs/lab5-check.bash</code>

# Give the '''lab5-check.bash''' file execute permissions (for the file owner).

# Run the shell script and if any warnings, make fixes and re-run shell script until you receive "congratulations" message.

#Arrange proof of the following on the screen: <blockquote>✓ '''centos2''' VM:<blockquote><ul><li>Output from '''ssm list''' command.</li><li>Proof that '''/archive''' has been mounted</li></ul></blockquote>✓ '''c7host''' Machine:<blockquote><ul><li>Proof of creation of the shell script: '''monitor-disk-space.bash'''</li><li>Crontab entry for '''root''' account</li><li>Run the '''lab5-check.bash''' script in front of your instructor (must have all <code> OK </code> messages)</li></ul></blockquote>✓ '''Lab5''' log-book filled out.

= Practice For Quizzes, Tests, Midterm & Final Exam =

[[Category:OPS235]]

[[Category:OPS235 Labs]]

[[Category:CentOS 7]]

[[Category:SSD2]]

[[Category:Digital Classroom]]

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