Changes

=Archiving Files, Compiling Logical Volume Management and Software Packages from Source, Managing ServicesPackage Management=[[Category:OPS235]][[Category:OPS235 Labs]]

==Overview== * In this lab, you are 're going to help conserve disk space by learning how to compress and decompress files that are stored on your computer server. In addition, you will learn alternative methods of how to install programs (decompressing zipped tarball archives and then compiling source code). * In addition, you will learn about how certain processes (services) work, and how the system administrator can manage these services (i.e. turn "on" and "off"). ==Objectives== #To create and use archive files (tar and tar.gz)#Compiling software packages from source code#Install an application from software development repositories using the bit utility#Customising file-system start-up:

* Completion and Instructor "Sign-off" of Lab 42: [[OPS235 Lab 4 2 - CentOS6]] 

|'''Archiving LVM Information Utilities:'''|'''Service LVM Management Utilities:'''|'''Additional Utilities:'''|- valign="top"

*[http://www.centos.org/docs/5/html/Deployment_Guide-en-US/s1-system-config-lvm.html system-config-lvm] (Tutorial)*[http://linuxmanpages.com/man8/lvextend.8.php lvextend]*[http://linuxmanpages.com/man8/resize2fs.8.php resize2fs]*[http://linuxmanpages.com/man1man8/tarlvcreate.18.php tarlvcreate]*[http://linuxmanpages.com/man1man8/gziplvreduce.18.php gziplvreduce]*[http://linuxmanpages.com/man1man8/gunzippvcreate.18.php gunzipzippvcreate]*[http://linuxmanpages.com/man1man8/makevgextend.18.php makevgextend]

*[http://linuxmanpages.com/man8/mount.8.php mount]*[http://linuxmanpages.com/man8/umount.8.php umount]*[http://linuxmanpages.com/man8/yum.8.php yum]*[http://linuxmanpages.com/man8/rpm.8.php rpm]|} ==Resources on the web==Additional links to tutorials and HOWTOs:'''Please read this page to get an overview of LVM:'''<br /><br />:* [[Logical Volume Management]] ('''Note:''' It is recommended to return to this guide as a reference when performing the next several investigations):* [http://fedoranews.org/alex/tutorial/rpm/ Using the RPM Utility]:*[http://www.centos.org/docs/5/html/Deployment_Guideyum/ Using the YUM Utility]   =Logical Volume Management (Introduction)= == Check Current LVM Information Prior to Performing Investigations == '''LVM''' ('''Logical Volume Management''') is used to manage hard disk drives / partitions for Unix/Linux systems. LVM provides more flexibility than just working with hard disks / hard disk partitions. '''Volume Groups''' are areas used to define '''Physical Volumes''' (i.e. hard disks, disk partitions, or other forms of storage devices). '''Logical Volumes''' are then used to relate directories (mount points) to a specific physical volume or for a "range" or "span" of physical volumes. Therefore, LVM allows more flexibility and growth potential for Linux systems (for example, having Logical volumes span multiple hard disks). CentOS uses LVM by default upon installation. Other Linux distributions may provide the capacity to install LVM, or later install and then use Logical Volume Management. '''Although the concept of LVM is simple, it takes practice and preparation (or "thinking ahead") in order to correctly use this valuable tool'''. It is important for students to gain an understanding of LVM, and how to manage their filesystems using LVM. It is recommended for students to read the following resource prior to this lab and/or return to the following resource while performing this lab: [[Logical Volume Management]] At this point, having completed [[OPS235 Lab 2 - CentOS6|Lab 2]] you should have roughly the following disk storage setup: ('''Note:''' These results are output from the '''vgs''', '''pvs''', and '''lvs''' commands that provide volume group, physical volume and logical volume information for each of the virtual machines that you created in lab2. Before proceeding, check these values with your own system to see if you are generally "on the right track".) * '''centos1'''  VG #PV #LV #SN Attr VSize VFree vg_centos1 1 2 0 wz--n- 9.50g 0  PV VG Fmt Attr PSize PFree /dev/vda3 vg_centos1 lvm2 a-- 9.50g 0  LV VG Attr LSize Origin Snap% Move Log Copy% Convert lv_root vg_centos1 -wi-ao 8.03g lv_swap vg_centos1 -wi-ao 1.47g  * '''centos2'''  VG #PV #LV #SN Attr VSize VFree vg_centos2 1 3 0 wz--n- 19.51g 7.77g  PV VG Fmt Attr PSize PFree /dev/vda2 vg_centos2 lvm2 a-- 19.51g 7.77g  LV VG Attr LSize Pool Origin Data% Move Log Cpy%Sync Convert lv_home vg_centos2 -wi-ao---- 1.95g lv_root vg_centos2 -wi-ao---- 7.81g lv_swap vg_centos2 -wi-ao---- 1.97g  * '''centos3 (Note: This VM has no GUI installed)''' VG #PV #LV #SN Attr VSize VFree vg_centos3 1 3 0 wz--n- 14.51g 4.54g  PV VG Fmt Attr PSize PFree /dev/vda3 vg_centos3 lvm2 a-- 14.51g 4.54g  LV VG Attr LSize Origin Snap% Move Log Copy% Convert lv_home vg_centos3 -wi-ao---- 1.00g lv_root vg_centos3 -wi-ao---- 8.00g lv_swap vg_centos3 -wi-ao---- 992.00m * '''c6host (i.e. "removable hard disk" or "disk pack")''' Does not use LVM. Confirm this using the same commands used above. {{Admon/note|VM Backups and Recovery|Most of these investigations will take place in your 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 2, and you can restore them if something goes wrong.<br /><br />'''Remember: if you did not create backups for all of your VMs, then you don't have any restoration points to fall-back to!'''|}} == Investigation 4: Extend the size of lv_root using command-line tools == Perform this investigation in centos3. Let's say that you have run out of disk space on your computer (centos3), you need more space on the root filesystem, perhaps to host more webpages or a larger database or new software. What are your options? Getting a replacement harddrive would probably require reinstallation of the operating system and backup/restore of the data. Because we're using LVM though - we can avoid that. We can add a new harddrive (which will serve as a physical volume) to the volume group, and extend the root logical volume to make use of the new available space. '''Perform the following operations to increase the size of lv_root in centos3:''' <u>'''<font>Steps:</font>'''</u> <ol> <li>Run the following commands and make note of the output:</li> <code>ls /dev/vd* pvs vgs lvs df -h</code> <li>Open the centos3 virtual machine console</li> <li>Go to the hardware details view</li> <li>Click "Add Hardware" and add a new storage device of 2GBs, make sure it's a VirtIO disk.</li> <li>Go back to the console view</li> <li>Run the same ls command (performed in step 1), what's changed?</li> <li>Now we'll make the new device as a physical volume, add it to the volume group, and extend lv_root:</li> <code>pvcreate /dev/vdb  vgextend vg_centos3 /dev/vdb  lvextend -L +2G -r vg_centos3/lv_root</code> <li>Now rerun the ls/pvs/vgs/lvs/df commands. What has changed and what caused those changes?</li> <li>Among the changes, note that your root filesystem is now 2GB bigger - and you have not even rebooted your machine!</li></ol> '''Answer the Investigation 4 observations / questions in your lab log book.''' == Investigation 5: How is LVM managed using system-config-lvm? == '''Perform this investigation on the VM named ''<u>centos2</u>''.'''[[Image:Ops235_lab4_1.png|thumb|right|Screenshot of system-config-lvm in CentOS. Click to enlarge.]]# Let's learn to administer (manage) our LVM graphically for our '''centos2''' Virtual Machine.<br />CentOS provides a tool called <code>system-config-lvm</code> to graphically administer LVM. The package is not installed by default, so you will need to install it by issuing: (<code>yum install system-config-lvm</code>).<ol> <li value="2">Use this tool to determine the current LVM configuration by clicking on the appropriate element and reading the properties in the right-hand panel -- write down the answers: <ol type="a"> <li>What are the names and sizes of the '''PV'''s?</li> <li>What is the name and size of the '''VG'''?</li> <li>What are the names and sizes of the '''LV'''s?</li> <li>Is there any space in the VG which is not allocated to a LV?</li> </ol> </li> <li>Increase the size of the home file-system to '''4 GB''': <ol type="a"> <li>Click on the LV containing the '''home''' filesystem.</li> <li>Click on ''Edit Properties''.</li> <li>Change the size to '''4 GB''' and click ''Ok''.</li> </ol> <li>Create a '''new 3G LV''' (LV Properties: linear) containing an ext4 filesystem named lv_archive and mount it at '''/archive''' <li>Backup <code>'''/etc'''</code> into <code>'''/archive'''</code></li></ol>::* Copy the files in /etc into the filesystem mounted at <code>/archive</code><br />(use the graphical tools or the command line. If using cp, remember to use the -R option).<ol> <li value="6">Shrink the size of <code>lv_archive</code> to '''1 GB'''.</li> <li>Try shrinking the home file-system. What happens? Why?</li></ol> '''Answer the Investigation 5 observations / questions in your lab log book.''' = Storage Setup (prior to starting Lab 4) = At this point, having completed [[OPS235 Lab 3 - CentOS6|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 /> * '''centos1'''  This VM has a GUI and no free space in the VG. VG #PV #LV #SN Attr VSize VFree vg_centos1 1 2 0 wz--n- 9.80G 0 LV VG Attr LSize lv_root vg_centos1 -wi-ao 8.83G lv_swap vg_centos1 -wi-ao 992.00M PV VG Fmt Attr PSize PFree /dev/vda2 vg_centos1 lvm2 a- 9.80G 0 * '''centos2'''  This VM has a GUI and free space in the VG. VG #PV #LV #SN Attr VSize VFree vg_centos2 1 4 0 wz--n- 19.51g 4.73g LV VG Attr LSize lv_archive vg_centos2 -wi-ao---- 1.00g lv_home vg_centos2 -wi-ao---- 4.00g lv_root vg_centos2 -wi-ao---- 7.81g lv_swap vg_centos2 -wi-ao---- 1.97g PV VG Fmt Attr PSize PFree /dev/vda2 vg_centos2 lvm2 a-- 19.51g 4.73g * '''centos3'''  This VM has no GUI installed. VG #PV #LV #SN Attr VSize VFree vg_centos3 2 3 0 wz--n- 16.50g 0 LV VG Attr LSize lv_home vg_centos3 -wi-ao---- 1.00g lv_root vg_centos3 -wi-ao---- 10.00g lv_swap vg_centos3 -wi-ao---- 992.00m PV VG Fmt Attr PSize PFree /dev/vda3 vg_centos3 lvm2 a-en-US 14.51g 2.54g /dev/s1vdb vg_centos3 lvm2 a-services-chkconfig 2.00g 2.00g * '''c6host (i.e. "disk pack")'''  /dev/sdc3 20G 3.7G 15G 20% / /dev/sdc2 29G 4.7G 23G 18% /home /dev/sdc1 97G 48G 45G 52% /var/lib/libvirt/images = Logical Volume Management (Continued) = {{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'''.}} == Resources == Please read this page to get an overview of LVM:[http://zenit.senecac.on.ca/wiki/index.php/Logical_Volume_Management Logical Volume Management] It is recommended to open another window(eg. '''right-click''', '''open in new tab or window''') to make reference to view LVM commands as you perform investigations 1 to 3. == Investigation 1: How are LVMs are managed using Command-Line Tools ==# You are going to repeat the same LVM management operations (as your did with the ''centos2'' VM in '''lab3'''), but you will using command-line tools in the '''centos3''' VM. Since the centos3 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::: a. Determine the current LVM configuration using the <code>pvs</code>, <code>vgs</code>, and <code>lvs</code> commands.:: b.Grow the home filesystem to 2G using the command <code>lvextend</code> and <code>resize2fs</code>.:: c.Create a new 2G LV containing an ext4 filesystem and mount it at /archive (use <code>mkdir</code>, <code>lvcreate</code>, <code>mkfs</code>, <code>mount</code>, edit the file <code>/etc/fstab</code> (read the resource: [https://wiki.archlinux.org/index.php/fstab https://wiki.archlinux.org/index.php/fstab] ), and then reboot to confirm automatic mount).:: d.Copy the contents of <code>/etc</code> into <code>/archive</code>.:: e.Shrink <code>lv_archive</code> to 1G (use <code>umount</code>, <code>resize2fs</code>, <code>lvreduce</code>, and <code>mount</code>) == Investigation 2: How can a PV be added to an existing VG using Command-Line Tools? ==# Add an additional 2 GB virtual disk to your ''<u>centos1</u>'' system, we will use it as an additional physical volume.# Do the rest of this investigation in the command line.# You should now have both <code>/dev/vda</code> and <code>/dev/vdb</code>.# Record the size of the volume group and the amount of free space (Hint: use a command that you learned in a previous lab).# Read the resource [http://tldp.org/HOWTO/Partition/fdisk_partitioning.html chkconfigPartitioning with fdisk] to learn how to properly create a partition with the fdisk command.# Use fdisk to partition /dev/vdb with a Linux single partition that fills the whole disk.# 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.# Mark ''vdb1'' as a physical volume usable by LVM.# Add the new physical volume to the existing volume group.# Verify that the volume group is larger and has more free space. {{Admon/note|Think!|The next part of this investigation requires some research, thought, and creativity.}}'''Using that additional space, create a separate filesystem for <code>/home</code>:'''# Create the logical volume <code>lv_home</code> (1G ext4)# Find a way to move the contents of <code>/home</code> onto it.# Change your system configuration so that the new filesystem is mounted on <code>/home</code> from now on. {{Admon/tip|SELinux relabelling may be required|Your system may report that the files are not present in the new /home filesystem when they are clearly there. This is due to the Security-Enhanced Linux system (SELinux) preventing access to the files, because the files were tampered with (moved) and are no longer recognized as home directory content. You can fix this problem by restoring the file context labels so that SELinux accepts the files as valid home directory content: <code>restorecon -r /home</code>}} == Investigation 3: How can I use fdisk to manage storage on my disk pack? =='''On your <u>c6host</u> (i.e. "disk pack"), using your choice of the GUI and/or command-line tools:'''# Create a new partition or logical drive ('''NOT a logical volume!''') - minimum 5G, leaving at least 10G free space in the extended partition.# Format that partition (i.e. put a filesystem on it).# Make sure it's mounted automatically on a mountpoint of your choosing (easiest is to create a new directory for a mountpoint). = Updated backup instructions = If you completed this lab correctly - please make sure you are still making full backups of your virtual machines. Remember adding a new harddrive to centos3? You will need to back up that drive as well. If you don't - you will only have half of your machine backed up, which is of no use for a recovery.