Difference between revisions of "OPS235 Lab 3 - CentOS7"

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=INVESTIGATION 2: Using the Yum Command for Local & Repository Installs=
 
=INVESTIGATION 2: Using the Yum Command for Local & Repository Installs=
  
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== Part 1: How do you query the RPM database? ==
 
  
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RPM maintains a database of installed software. This information is very useful to system administrators. In the previous lab you queried that database using RPM with the -q argument. When you query the RPM database, you can separately specify:
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== Part 1: Install and Remove Software with Yum ==
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:* Do an <u>operational task</u> on one or more packages (like installing or removing a package), using a '''select-option'''
 
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:* What <u>information</u> you want about those packages, using a '''query-option'''
 
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'''Perform the following steps:'''
 
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(Perform investigations 1 - 3 in your host machine (c6host)
 
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# Using information from the man page for <code>rpm</code>, fill in this information:
 
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'''Answer the Investigation 1 observations / table contents in your lab log book.'''
 
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== Part 2: How do you install and remove software with RPM? ==
 
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# Use the graphical file manager (Nautilus) to change to the directory on your Installation DVD. Go to the sub-directory called '''Packages'''. It should contain a file called: <code>lynx-2.8.6-27.el6.x86_64.rpm</code>
 
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# Execute the following command: <code>rpm -i lynx-2.8.6-27.el6.x86_64.rpm</code>
 
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# Issue an RPM query to check that lynx is installed. Record this command in your lab log-book.
 
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# Issue the following command: <code>rpm -e lynx</code>
 
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# Issue an RPM query to verify that lynx is no longer installed. Record this command in your lab log-book.
 
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# Issue the following command:  <code>rpm -i elinks-0.12.rpm</code>. Did it work? Explain in your lab log-book why this command may not have worked.
 
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'''Answer the Investigation 2 observations / questions in your lab log book.'''
 
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== Part 3: How do you install and remove software with ''yum''? ==
 
  
 
{{Admon/note|Internet Connection|In order for yum to work you require a connection to the Internet. Establish this connection by using the browser to log into SeneNET}}
 
{{Admon/note|Internet Connection|In order for yum to work you require a connection to the Internet. Establish this connection by using the browser to log into SeneNET}}
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'''Answer the Investigation 3 observations / questions in your lab log book.'''
 
'''Answer the Investigation 3 observations / questions in your lab log book.'''
  
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==Part 2: Managing Repositories with Yum==
  
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ADD THIS SECTION
  
 
= INVESTIGATION 3: LOOKING AHEAD =
 
= INVESTIGATION 3: LOOKING AHEAD =
  
 
==Part 1: Automating Routine Tasks (Shell Scripting)==
 
==Part 1: Automating Routine Tasks (Shell Scripting)==
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[[Image:lab2_text_1.png|thumb|right|275px|When executed as '''root''' or using '''sudo''' command, provides VM status and opportunity to '''start''' VMs in a text-based interface]]
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x
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We continue the discussion of using Bash Shell Scripts to help automate routine tasks for the Linux system administrator. In lab1, you were exposed to  downloading and running Bash Shell Scripts for demonstration purposes. Before showing you demos for this lab, you should learn a few more "shell scripting tricks" in case you need to create your own set of tools for task automation.
 
  
  
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#Click on the following link to run an online tutorial showing you some additional shell scripting techniques: [ link ].
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#x
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#It is recommended to practice creating Bash Shell Scripts as you proceed throughout this course.
 
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#Let's look at some demos involving managing VMs with shell scripts. Issue the following command:<blockquote><b><code><span  style="pointer-events: none;cursor: default;color:#3366CC;">wget https://scs.senecac.on.ca/~elizabeth.kopiec/backupVM.bash</span></code></b></blockquote>
 
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#Set the appropriate permissions and run this Bash Shell script.
 
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#Verify that the backup of your virtual machine occurred (hint: issue ls command to verify the date and time of creation).
 
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#Use the <b><code>wget</code></b> command to download, study, and run the following shell scripts on-line:<blockquote><b><code><span style=" pointer-events:none;cursor:default;color:#3366CC;">https://scs.senecac.on.ca/~murray.saul/vm-start-text.bash<br>https://scs.senecac.on.ca/~murray.saul/vm-stop-text.bash</span></code></b><br><b><code><span style=" pointer-events:none;cursor:default;color:#3366CC;">https://scs.senecac.on.ca/~murray.saul/vm-start.bash<br>https://scs.senecac.on.ca/~murray.saul/vm-stop.bash</span></code></b></blockquote>
 
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#Try to understand what these Bash Shell scripts do.
 
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#You have completed lab2. Proceed to Completing The Lab, and follow the instructions for "lab sign-off".
 
  
 
'''Answer all observations / questions in your lab log book.'''
 
'''Answer all observations / questions in your lab log book.'''
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{{Admon/important|Time for a new backup!|If you have successfully completed this lab, make a new backup of your virtual machines.}}
 
{{Admon/important|Time for a new backup!|If you have successfully completed this lab, make a new backup of your virtual machines.}}
  
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'''Notes:'''
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'''Arrange evidence for each of these items on your screen, then ask your instructor to review them and sign off on the lab's completion:'''
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# rpm command options
 
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# yum command options
 
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# How to use pvs/vgs/lvs/df/pvcreate/vgextend/lvextend
 
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# Answer to this question "What is the license of the nautilus package?"
 
  
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'''Arrange evidence for each of these items on your screen, then ask your instructor to review them and sign off on the lab's completion:'''
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# Archived files created
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# elinks application removed on the host (disk pack - main system c6host).
 
 
# Unnecessary/unused packages have been deleted (list at least 4, and show that they are no longer installed).
 
# Unnecessary/unused packages have been deleted (list at least 4, and show that they are no longer installed).
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# Fresh backup of the virtual machines.
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# 2 packages installed with yum command
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# 1 repository added for yum
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# License of the nautilus package
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==Preparing for Quizzes==
 
==Preparing for Quizzes==
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Revision as of 11:53, 28 March 2015


LAB PREPARATION

Purpose / Objectives of Lab3

In this lab, you are 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.

Topics include:

  1. Creating and using archive files (tar and tar.gz)
  2. Compiling software packages from source code
  3. Install applications using various methods:
  • Decompressing source code archive, and compiling source code
  • Use yum utility to install software from local programs (on DVD drive)
  • Use yum utility to install software from repositories (online storage areas)
  1. Demonstrating the use of Bash Shell scripts to automate routine tasks


Required Materials / Lab Preparation

CentOS7
FULL DVD
Removable Hard Disk Pack (SATA)
USB key
(for backups)
Lab3 Log Book

My Toolkit (CLI Reference)

Archiving / Compiling:

tar
gzip, gunzip
make

Software Manangement:

rpm
yum

Commands

ls
more
wget
chmod
vi

Idea.png
Online Linux Command Review
The following links will allow you to practice Linux commands that you learned from ULI101:
  • Bash Shell Scripting Continued: [ ]


INVESTIGATION 1: ARCHIVING FILES

Part 1: Creating a File Archive

Note.png
Use centos3
Perform these steps in the centos3 virtual machine.
  1. Boot up your centos3 VM.
  2. Change your working directory to /usr/share/doc/sudo*
  3. Use the tar (tape archiver) command to create an archive file named /tmp/archive1.tar
    • tar cvf /tmp/archive1.tar .
Important.png
Warning!
Don't miss the . at the end of the tar commands below! It specifies what should go into the archive: the contents of the current directory.
  1. What do the options c, v, and f mean?
  2. Record the archive file size.
  3. Compress the file using gzip:
    • gzip /tmp/archive1.tar
  4. Record the archive file size after compression.
  5. Make sure you're still in /usr/share/doc/sudo* and then create a compressed archive:
    • tar cvzf /tmp/archive2.tgz .
  6. What does the z option do?
  7. Compare the sizes of /tmp/archive1.tar.gz and /tmp/archive2.tgz. Why are they so close in size?

Answer the Part 1 observations / questions in your lab log book.

Part 2: Restoring Files From an Archive

Note.png
Remain in your centos3 VM
Perform these steps in the centos3 virtual machine.
  1. Create the directory /tmp/extract1
  2. Change to the /tmp/extract1 directory.
  3. Move the file archive1.tar.gz to your current directory.
  4. Unzip the first archive you created:
    • gunzip archive1.tar.gz
  5. Extract the files from the first archive:
    • tar xvf archive1.tar
  6. Are all the files there?
  7. Compare /tmp/extract1/README and /usr/share/doc/sudo*/README. Are they exactly the same? Why?
  8. Create the directory /tmp/extract2
  9. Move the file archive2.tgz to the /tmp/extract2 directory.
  10. Extract the files from the second archive:
    • tar xvzf /tmp/extract2/archive2.tgz
  11. Note that this time a separate gunzip command was not needed. Why?
  12. Repeat the previous command, leaving out the option "z". Does it work? Why?
  13. Compare the README file in this directory with the original file. Are they exactly the same?

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


Part 3: Compiling Source Code from Archive File

Now that you know how to create and decompress "zipped tarball archives", we will demonstrate how to install applications from websites containing these types of archives. Although this method is not as "user-friendly" as using the yum or rpm command, this method is useful if the application is NOT contained in regular software repositories...

Note.png
Use centos2
Perform these steps in the centos2 virtual machine.

In order to build software from source code, you must have the appropriate software development tools (such as make and gcc) and libraries (such as GTK) installed. The required tools will vary depending on the computer languages used in the software being built.

  1. Issue the following command to install a basic set of development tools and libraries:
    yum groupinstall "Development Tools" "Development Libraries"
Note.png
Installing Development Libraries
In the future, remember the above procedure whenever installing software from source. Sometimes, you need to install additional tools or libraries in order to compile a particular software package
  1. Go to the directory /tmp
  2. Use the wget command to download the "tar ball" that contains the source code for the NLED text editor. wget is a command-line tool to download files from the web using the http or ftp protocols.
  3. Extract the files. Change to the newly-extracted directory (/tmp/nled-2.52)
  4. Check to see if there is a file named configure. If so, run it; if not, skip this step. (Most but not all source code archives contain this file)
  5. Check to see if there is a file named Makefile or makefile. If so, type the command:
    • make
    • Did the command work? Why? Use the yum command to install the package gcc. What do you think the package gcc does?
  6. Reissue the make command. Where you successful? What does make do?
  7. Issue the command as root: yum list ncurses. What do you see? Issue the command at root: yum search ncurses. What do you observe?
  8. In this case, you need to install the ncurses development libraries as well. Issue the following command as root: yum install ncurses-devel.x86_64. Now issue the command: make
  9. Some software distributed as source code can automatically install itself. Try this command:
    • make install
  10. Most but not all source code archives include the capability of installing themselves this way.
  11. If the command make install does not work (how can you tell? What command did you learn from ULI101 to confirm that this command cannot be run from the command line?), copy the nled program manually:
    • cp nled /usr/local/bin
  12. Test nled to make sure it works.
  13. Why did copying the nled executable to /usr/local/bin allow the nled command to be run by name anywhere in the command prompt?

Answer the Investigation 3 observations / questions in your lab log book.

INVESTIGATION 2: Using the Yum Command for Local & Repository Installs

Part 1: Install and Remove Software with Yum

Note.png
Internet Connection
In order for yum to work you require a connection to the Internet. Establish this connection by using the browser to log into SeneNET
  1. Change to your home directory.
  1. Issue the command: yum install elinks and answer y to the question about installation.
    1. Where did yum get the elinks software?
    2. Why could yum install elinks when rpm couldn't?
  2. Issue an RPM query to verify that elinks is installed. Record this command in your lab log-book.
  3. Issue the command: yum remove elinks
  4. Issue an RPM query to verify that elinks is no longer installed. Record this command in your lab log-book.
  5. Issue this command: yum info cups
  • Based on the result, do you think that cups is a useful package for your system? If not, try removing it.
  1. Unused and unneeded software can present a security risk and ties up disk space needlessly. Find at least 4 other packages (for example: games, sound & video, etc) that you're not using on your system, and remove them. Be careful to ensure that removing those packages does not also remove other software that you do need.

Answer the Investigation 3 observations / questions in your lab log book.

Part 2: Managing Repositories with Yum

ADD THIS SECTION

INVESTIGATION 3: LOOKING AHEAD

Part 1: Automating Routine Tasks (Shell Scripting)

x


  1. x

Answer all observations / questions in your lab log book.

Completing the lab

Important.png
Time for a new backup!
If you have successfully completed this lab, make a new backup of your virtual machines.

Arrange evidence for each of these items on your screen, then ask your instructor to review them and sign off on the lab's completion:

  1. Archived files created
  2. Unnecessary/unused packages have been deleted (list at least 4, and show that they are no longer installed).
  1. 2 packages installed with yum command
  2. 1 repository added for yum
  3. License of the nautilus package


Preparing for Quizzes

  1. What is the advantage of disabling services such as bluetooth?
  2. What is the difference between a .tgz file and a .tar.gz file? What do these stand for?
  3. What is the purpose of a repository?
  4. What is source code?
  5. How do you build software from source code?
  6. Which is preferred: installing from an RPM file, or installing from source code? Why?
  7. How do you use service/init/chkconfig to:
    • show/set current runlevel
    • list services
    • stop a service
    • start a service
    • Why is it important to learn how to manage services?
    • Why is it important to stop certain services?
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