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[[Category:OPS235]][[Category:OPS235 Labs]]
{{Admon/caution|THIS IS AN OLD VERSION OF THE LAB|'''This is an archived version. Do not use this in your OPS235 course.'''}}
= Storage Setup (prior to starting Lab 4) =
At this point, having completed [[OPS235 Lab 3|Lab 3]] you should have <u>roughly</u> the following disk storage setup:<br />
('''Note:''' These results are output from the '''vgs''', '''lvs''', and '''pvs''' commands within each virtual machine. You will be using these commands in the following lab investigations)<br /><br />
This VM has a GUI and free space in the VG.
VG #PV #LV #SN Attr VSize VFree
vg_fedora2 1 3 0 wz--n- 14.80G 4.07G
LV VG Attr LSize
lv_home vg_fedora2 -wi-ao 1.95G
lv_root vg_fedora2 -wi-ao 7.81G
lv_swap vg_fedora2 -wi-ao 992.00M
PV VG Fmt Attr PSize PFree
/dev/vda2 vg_fedora2 lvm2 a- 14.80G 4.07G
This VM has no GUI installed. VG #PV #LV #Identify and define major entries in the <code>/etc/passwd</code>, <code>/etc/shadow</code>, and <code>/etc/group</code> filesSN Attr VSize VFree vg_fedora3 1 3 0 wz--n- 9.80G 3.83G LV VG Attr LSize #Learn about partitions, and how to add "virtual partitions with LVM lv_home vg_fedora3 -wi-ao 1.00G #Learn how to create a "virtual partition" in a Virtual Machine lv_root vg_fedora3 -wi-ao 4.00G #Learn how to add and remove and modify user accounts lv_swap vg_fedora3 -wi-ao 992.00M #Learn how to create and manage groups PV VG Fmt Attr PSize PFree /dev/vda2 vg_fedora3 lvm2 a- 9.80G 3.83G
* '''f17host (i.e. "disk pack")'''
{{Admon/note|Recovering VMs|'''Most of these investigations will take place in you virtual machines.''' If you make a significant mistake, your virtual machine may not boot. Remember that you created backups of your virtual machines in Lab 3, and you can '''restore them if something goes wrong'''.}}
==PrerequisitesResources ==
==Linux Investigation 1: How are LVMs are managed using Command Online Reference-Line Tools ==Each Link below displays online manpages for # You are going to repeat the same LVM management operations (as your did with the ''fedora2'' VM in '''lab3'''), but you will using command-line tools in the '''fedora 3''' VM. Since the fedora3 VM only operates in command-line mode, you will need to refer to the '''"Logical Volume Management"''' link above.# Write down the exact commands used at each step, and record appropriate command output:## Determine the current LVM configuration using the <code>pvs</code>, <code>vgs</code>, and <code>lvs</code> command.## Grow the home filesystem to 2G using the command <code>lvextend</code> and <code>resize2fs</code>.## Create a new 2G LV containing an ext4 filesystem and mount it at /archive (via [http:use <code>lvcreate</code>, <code>mkfs</code>, <code>mount</code>, edit the file <code>/etc/fstab</linuxmanpagescode>, and then reboot to confirm automatic mount).com## Copy the contents of <code>/ http:etc</code> into <code>/archive</linuxmanpagescode>.com]## Shrink <code>lv_archive</code> to 1G (use <code>umount</code>, <code>resize2fs</code>, <code>lvreduce</code>, and <code>mount</code>):
# Shutdown ''fedora1'' if it is running.
# Open the console window for '''''fedora1'''''.# Select the menu option '''View'''>'''Details'''.# Click '''''Add Hardware''''' button at the bottom left-hand corner.# Make certain to remain in In the default section called ''Adding new virtual hardware'' window that appears, select a Hardware Type of ''"Storagestorage"'' and click ''"Forward"''.# Make the following selections in this certain option "StorageManaged or other existing storage" dialog box: [[Image:lab4_inv_1is selected.png|thumb|right|400px|Suggested settings in Click on the ''Browse'Storage'button, then click on '' dialog box to create a 'New Volume''.# Give the new virtual Hard Diskdisk file a name of <code>fedora1b</code>, a format of ''raw'.]] ::* Under '''Create , with a disk image on the Computer's Hard Drive'Max Capacity'', change the size to and '''2 GB'Allocation''of 2000 MB.::* Click on '''Select Managed or Other Existing Storage'Finish''. You can specify a file pathname for # Select the Hard Drive (refer to diagram). If no new virtual disk file pathname is provided, then the system will assign a name in the directory <code>/var/lib/libvirt/images/</code>''fedora1b.::* Select Device Type: img''and click 'Virtio Disk'Choose Volume''.::* # Select Storage Format: a device type of ''Virtio Disk'raw'.# Finish creating the new virtual disk by clicking ''::* Click Forward''and then 'FINISH'Finish'' to proceed. <ol> <li value="8"># Boot the system. You should now have both <code>/dev/vda</code> and <code>/dev/vdb</code>.</li> <li># Record the size of the volume group and the amount of free space (Hint: use a command that you learned in a previous lab).</li> <li>Refer to the following tutorial to use the <code>fdisk</code> command: [http://tldp.org/HOWTO/# Partition/fdisk_partitioning.html Partitioning with fdisk]</li> <li>Use the <code>fdisk</code> command to create a primary partition for <code>/dev/vdb</code> with a single partition (number 1) that fills the whole disk.</li> <li># Check the messages printed when <code>fdisk</code> exits -- you may need to reboot the system in order for the new partition table to take effect.</li> <li># Run this command to format the physical volume: <code>pvcreate /dev/''vdb1''</code></li> <li># Add the new physical volume to the existing volume group: <code>vgextend ''nameOfVolumeGroup'' /dev/vdb1</code></li> <li># Verify that the volume group is larger and has more free space.</li></ol> '''Answer the Investigation 1 observations / questions in your lab log book.''' == Investigation 2: How to Add a PV to an existing VG (Command Line Method) == '''The investigation relate to ''<u>fedora3</u>''. Although you are NOT required to issue the Linux commands, you are required to record them in your lab log-book.''' # You are going to only write in your Lab4 Log-book the Linux commands to perform the same operation that you did graphically in Investigation #1.# You are NOT required to issue these commands on your Fedora3 VM, and it will NOT work since there is no extra room on the VM to create a virtual hard disk# Make reference to the following command line resource for assistance: [[Logical Volume Management]]::*'''(Hint:''' First view section on '''Adding a Physical Volume'''. Also, write down the commands first and check prior to issuing them in sequence.) '''Answer the Investigation 2 observations / questions in your lab log book.''' == Investigation 3: Manually Mounting / Unmounting Partitions == '''Perform this investigation on the VM named ''<u>fedora2</u>''.''' So far, we have simply assumed that when the Fedora OS boots-up, that its file-system is automatically available. In this investigation, you will learn how file-systems (or portions of file-systems) can be mounted or "connected" to existing file-systems. You will also learn how to unmount (or "disconnect") portions of file-systems from existing file-systems. # Boot-up your '''Fedora2''' VM.# Open a terminal and login as root.# Issue the command called '''mount''' . This command provides information relating to various partitions (logical volumes) and corresponding "mount points" (directories).# Record the information from issuing the <code>mount</code> command for both '''lv_root''' and '''lv_home'''. What commands would issue to quickly obtain this information?# Issue the command '''umount /archive'''. Did anything happen? Issue the '''mount''' command again. Is there any difference with the command output?# View the online man pages for the [http://linuxmanpages.com/man8/mount.8.php mount] command. Issue the <code>mount</code> command with arguments to "re-connect" the device '''/dev/mapper/vg_fedora2-lv_archive''' to the '''/archive''' directory (refer to the section '''Linux Command Online Reference''' above).
{{Admon/note|File-System Type Option No Longer Required for Mount CommandThink!|When viewing examples onlineThe next part of this investigation requires some research, thought, you may notice and creativity.}}'''Using that additional space, create a separate filesystem for <code>/home</code>:'''# Create the -t option is used with the mount command logical volume <code>lv_home</code> (1G ext4)# Find a way to indicate move the version or type contents of file-<code>/home</code> onto it.# Change your system to mount.configuration so that the new filesystem is mounted on <code>/home<br /code>'''The -t option is no longer required for the mount command''',|}}from now on.
== Investigation 3: How can I use LVM to manage storage on my disk pack? =='''Answer On your <u>f17host</u> (i.e. "disk pack"), using your choice of the Investigation 3 observations GUI and/ questions in your lab log book.or command-line tools:'''# Create a new logical partition ('''NOT a logical volume!''') - minimum 5G, leaving at least 10G free space in the extended partition.# Add that partition as a PV into the existing VG (using the commands you used in the previous investigation).# Grow the root filesystem to fill the available space.
= User/Group Management =
== Investigation 54: The /etc/passwd file == '''Perform this investigation on the VM named ''<u>f16host</u>''.'''
# Look at the /etc/passwd file.
# Make note of the contents of that file.
# Read about the file: http://linux.die.net/man/5/passwd
# Why do you think there are so many users?
# Look at the names of the users. What do you think these user names represent? Are they people?
# The user IDs of real users (people) are different from the user IDs of system accounts. What is the pattern?
# Read the man page for the '''useradd''' command.# Create a new user account for each of your pod-mates, using their learn account name as a user name. Give each user a password.# Use Grep the grep command to obtain information /etc/passwd file for each of the newly created new users within the '''/etc/passwd''' file.
#* What is the home directory of each user?
#* What group is each user in?
#* Grep the /etc/shadow file for each of the new users.
#* Make note of this information.
# Create two new dummy users, ops235_1 and ops235_2.
# Investigate the home directory of one of your new users.
#* What files are there? Be sure to include hidden files.
#* What do you think these files are used for <span class="plainlinks">?#* How does the operating system determine which files are created in a new home account? <br />The answer can be found here: http://www.linuxhowtos.org/Tips%20and%20Tricks/using_skel.htm
#* Look at the files (including hidden files) in the template directory referred to in the article. Compare them to what is in a home directory for a new user. What do you notice?
#* Create a new file in this directory with the following command: <code>touch foo</code>
#* Create a new user named foobar, with the option to automatically create a home directory.
#* Look at the contents of foobar's home directory. What do you notice?
# Be sure to record your observations in your lab notes.
== Investigation 76: Managing Groups ==
{{Admon/note|Use fedora1|Perform these steps in the '''fedora1''' virtual machine.}}
# Read the man page for the '''groupadd''' and '''groupdel''' commands.
# Note which option allows you to set the Group ID number (GID) when you create a new group.
# Examine the file <code>/etc/group</code><ol type="a"><li>#* Which values of GID are reserved for system accounts?</li><li>#* Which values of GID are reserved for non-system user accounts?</li><li>#8 What is the lowest available GID number for non-system users?</li><li>#* What is the default group name of a new user?</li><li>#* Add a new group named <code>ops235</code> with a GID of <code>600</code>.</li><li>#* You are angry at some irresponsible users on your system. <ul><li>#** Add a new group named <code>idiots</code>.</li><li>#** Look at <code>/etc/group</code> and note the GID of idiots.</li><li>#** What GID is given to a new group if if you do not specify it?</li><li>#** Your anger has subsided. Delete the <code>idiots</code> group.</li><li>#** Look at <code>/etc/group</code> again and note the change.</li></ul></li></ol>
Be sure to record your observations in your lab notes.
{{Admon/note|Use fedora1|Perform these steps in the '''fedora1''' virtual machine.}}
# Read the man page for the '''userdel''' command. Note which option automatically removes the users home directory when that user is deleted.
# Delete the user ops235_1 using the command <code>userdel ops235_1</code>
# Delete the user <code>ops235_2</code> using the same command with the option which removes the home directory of the user.# Check the contents of the <code>/home</code> directory. What do you notice?# Check the contents of the <code>/etc/group</code> directoryfile. What do you notice?
== Investigation 8: Modifying users ==
# Read the man page for the usermod command. Note which options change the user's full name, primary group, supplementary groups, and shell.
# Examine <code>/etc/group</code>. What has changed?
# Be sure to record your observations in your lab notes.
<!-- == Investigation 13: Security Tip: Removing Unnecessary Users and Groups ==
#* nscd (if not using nscd)
#* uucp -->
= Completing the lab =
Arrange proof of the following on the screen:
# Two PVs on '''fedora1'''.
# Separate <code>/home</code> filesystem (on an LV) in '''fedora1'''.
<!-- # Unnecessary accounts and groups have been removed on '''fedora1'''. -->
# Account created on '''fedora3''' matching your Matrix account.
# List contents of '''/etc/group''' file (ops235 group).# List contents of '''/etc/passwd''' file (created accounts).# Fresh backup of the virtual machines.
= Preparing for the Quizzes =
# What is a VG? PV? LV? # What is the total size of the "main" VG on your system?# How do you create a LV?# How do you delete an LV?# How would you add the disk partition <code>/dev/sdb7</code> to your volume group "main"?# How would you increase the size of the root filesystem by 50 MB?
# What is the purpose of <code>/etc/fstab</code>?
# What did you have to do in order to move is the home directories onto a new filesystem? Whypurpose of <code>/etc/shadow</code>?