OPS235 Lab 1 - CentOS7 - SSD

LAB PREPARATION

The VMware Workstation 12 application will allow you to create and administer 4 different virtual machines (VMs) on your computer system.

Purpose of Lab 1

In order to save money and resources when learning to install, manage, and network various Linux machines for this course, we will be using virtualization for this course. In previous courses, students were required to purchase a removable hard disk drive to complete this course. You are NOT required to use a removable hard-drive for this course. On the other hand, it is ESSENTIAL to have a Solid State Drive (SSD) with a minimum storage capacity of 128 GB to perform your lab sessions and provide a host for your other Centos7 VMs that you will create in lab2.

Main Objectives

• Correctly install the CentOS 7 FULL INSTALL DVD (not LIVE DVD) on your removable hard disk.

• Record installation characteristics of CentOS 7 FULL INSTALL in a chart (contained in lab2 logbook chart) to compare with other installation methods performed in lab2.

• Verify correct settings prior to proceeding with host installation stages.

• Obtain Linux server information after installation to create a software asset report for later access.

• Disable Linux Kernel security enhancements to allow easier internal networking connections (to be reactivated in a later lab).

• Observe that Bash Shell Scripts can automate routine tasks (such as generating system information reports).

Minimum Required Materials			Linux Command Reference
CentOS 7 FULL INSTALL DVD	Solid State Drive (SSD) (Minimum size: 128GB)	Lab Log Book (labs 1 & 2)	Package Management rpm yum System Information hostname uname ps lsblk Networking ifconfig netstat route nslookup	Miscellaneous grep wc pwd ls more file wget chmod scp vi	Matrix on-line tutorials Linux Basics: /home/murray.saul/linux-basics Using the vi Text Editor: /home/murray.saul/vi-tutorial

INVESTIGATION 1: CREATE HOST MACHINE (c7host)

For the next 3 investigations, you will learn how to install your Centos Full DVD onto your removable hard disk. You will customize your install to setup several separate partitions:

• / (The "root" partition)
• /home (Store regular user accounts)
• /var/lib/libvirt/images (store virtual machine images to be created in lab2)
• swap partition (Virtual Memory)

Make certain to record your observations of this install in the comparison chart for c7host in your lab2 logbook.

Part 1: Start Installation

Host Machine Details:

• Name: c7host
• Boot media / Installation: CentOS7 Full Install DVD
• Memory: 16GB
• Disk space: 128GB (or higher)
• CPUs: 1

You're supposed to use this hard drive only for this course But if you really need to use it for two courses, and the professor for the other (probably windows) course will allow it - ask your professor for help with partitioning.
comparison chart in lab2 logbook.	The Installation Summary screen provides flexibly when configuring to install on your computer.

1. Refer to this listing of installation screenshots if you need a reference:
   [ installation screenshots ]
   
2. Insert your removable SATA hard disk into the drive tray.
3. Set your computer's drive selector switch to external (a.k.a position #4).
4. Power up the computer and insert the CentOS 7 Installation DVD into the DVD drive, then power-off computer.
5. Newer computer models are labelled HP Z230.
   
   NOTES:
   • If you are using the newer model, allow the computer to boot up (without pressing F10 key) to boot from DVD.
   • Refer to the comparison chart in lab2 lab logbook, and fill in various installation information for c7host while you perform the installation (such as time it took to perform a full install, installation options, etc).
     
     

6. Power on the computer again, and after booting from the CD, select from the installation menu: Install Centos7.
   
   Note: If you experience unreadable display after you boot into your installed system, you can redo the install, but select from the install menu: Troubleshooting and then select Install in Basic Graphics Mode.
   
   
7. Next, you will be prompted for a language. In the first screen, select language English with subselection English-Canada and then click the Continue button on the bottom right-hand screen.
8. The Install Summary should now appear. This screen allows the installer to customize their Centos7 system prior to installation.
9. Configure the following installation settings from the Install Summary Screen:
   
   DATE & TIME:
   • Click on the Map to select Toronto area (you may also select from the drop-down menu section)
   • Click the DONE button at the top-left corner to finish and return to the Installation Summary screen.
   
   NETWORK & HOSTNAME:
   • Select the default Ethernet connection and click the button on the top right-hand side to change the setting from OFF to ON.
   • At the bottom left-hand corner type the hostname: c7host (all lowercase letters)
   • Review your settings, then click the DONE button at the top-left corner to finish and return to the Installation Summary screen.
   
   SOFTWARE SELECTION:
   • Select the software packages labelled: Gnome Desktop
   • Click the DONE button at the top-left corner to finish and return to the Installation Summary screen.
   
   
10. Although the Centos installtion program can provide suggestions on how to partition your hard disk, you will be customizing partitions for your hard disk. This custom partitioning is important since it will have consequences on future labs that you perform (especially for lab2).

Part 2: Custom Partitioning

Mount Points and Linux File System Types Similar to other Operating Systems like windows fat / vfat / ntfs file system types, it is good to know a few common file system types in Linux for comparison: xfs:   Newer filesystem (fast transfer rates for large files, Journaling) ext4:   Newer filesystem supporting large files and Journaling (used in for this lab) ext2:   Stable filesystem popular for databases (no journaling)

Carefully verify partition mount-names and sizes prior to proceeding with install. Check installation screenshots link for verification.

1. From the installation summary screen, click Installation Destination.
2. In the installation destination screen, select the destination option: I will configure partitioning and then click Done.
3. The manual partitioning screen should appear.
4. If you have used your hard disk for previous Linux (Centos) distributions, you should remove them. Click on the distribution, and for each partition, select the partition and click the remove button (minus sign) and confirm deletion.
5. Change the option New mount points will use the following partition scheme from LVM to Standard Partition (you will not be using LVM for your c7host machine).
6. Before you proceed with creating partitions, let's see the partitions that we need to create for our host computer:
   • Primary Partitions (ext4):
     • 20GB for / (i.e. "root")
     • 30GB for /home
     • 60GB for /var/lib/libvirt/images
   • Swap Partition:
     • 16GB (Note: "swap" must be selected from the drop down menu)
   
   NOTE: Remember that the sizes are recorded in MB (eg. 30 GB = 30000 MB) and you should multiply GB by a factor of 1024 to get the correct size.
   (eg. 30 GB x 1024 = 30720 MB)
   
   
7. We will now create the root (/) partition. Click on the add button (plus) sign.
   
8. In the Add a New Mount Point screen, select / as the mount-point (either by typing or selecting from drop-down menu), and enter 30720 in for partition size and click Add Mount Point button.
9. You will return to the previous dialog box.
   For the / partition, change the file-system type from xfs to ext4 and make certain that the Device Type is set to Standard Partition (not LVM). You need to repeat this procedure for the /home and /var/lib/libvirt/images partitions as well).
10. Repeat the same steps above for the /home partition and /var/lib/libvirt/images partition. You need to type the /var/lib/libvirt/images partition since it does not appear in the drop-down menu.
11. Recheck each of the created partitions, and make certain that the file-system type is set to ext4 and the Device Type is set to Standard Partition.
12. Finally, add a swap partition (Mount Point: swap) for 16 GB.
13. Check that your partition settings are correct (you can ask your instructor or lab monitor to confirm), and then click Done (possibly twice) in order to proceed
    
    NOTE: If there is an error message associated with your created partitions, you may need to add a /boot/efi partition (as a new mount). The capacity should be: 2954MB (i.e. 2,954 MB). Once finished, click Done.
    
    
14. A Summary of Changes screen will appear to show the partitioning operations that will be created. Click the Accept Changes and click Begin Installation in the Installation Summary screen to proceed with the installation.
15. Start timing your host machine installation.

Part 3: Completing the Installation

This screen indicates that installation is complete. You should remove the install DVD and confirm Centos7 boots from your removable hard drive.

1. During the installation process, you will required to create a root password (for administration access) and create a regular user account. Click on Root Password and enter your root password. Think of an appropriate password and record that password somewhere in case you forget! An indicator will appear to show you how secure your password is. Retype your root password and click Done (you may have to click Done twice if your password is not considered to be a strong password).
2. You need to create a regular user account. This account will be used to graphical log into your host machine. It is never recommended to graphically log into a graphical Linux/Unix system as root. It is better to log into a regular user account, then run a command to login as root (you will learn how to do this later in this lab).
3. Click User Creation and enter your full name, username, and an appropriate password (and confirm password). Click Done to finish (click twice if password is not considered to be a strong password).
4. Remember to record this host installation information in the installation comparison chart in the lab2 logbook.
5. When installation is complete, you will notice a message at the bottom of the screen stating: CentOS is now successfully installed and ready for you to use!
6. Click the Reboot button. Your DVD will briefly open in the DVD drive bay. Make certain to remove this installation DVD so that Centos will boot from your hard drive.
7. After the system reboots, a boot menu should briefly appear, then prompt the user to accept the License Information (this is only a one-time occurrence).
   In order to accept the license agreement, issue the following keystrokes:
   
   1 followed by ENTER (to select the license agreement prompt
   2 followed by ENTER (to accept the license agreement)
   c followed by ENTER (to save the selection)
   c followed by ENTER (a second time to continue booting into the system)
   
   
8. The system should then graphically prompt the user to login with their regular user account. Click on your regular user account name and enter your regular user password.
   
   
9. The last phase of the installation process should now run:
   • Confirm English as the default input source and click Next.
   • Skip the creation of online accounts by clicking Next.
   • Start using your installed Linux system by clicking Start Using CentOS Linux.
   
   
10. Stop timing your installation and note the amount of time that your installation took to perform. Also take the time to fill in the c7host section of the installation comparison chart in your lab2 logbook.
11. Open a web-browser and check to see if you can connect to the Internet.
    
    

Answer Investigation 1 observations (all parts and questions) in your lab log book.

INVESTIGATION 2: COMMON POST-INSTALL TASKS

Part 1: Turning Off Locked Screen-saver

Your system automatically enables a screen-saver application which is a useful security tool to prevent unauthorized viewing of information on a terminal after a certain amount of inactivity. Turning-off the locked screen-saver for this (and other) virtual machine can be useful when waiting for your instructor to come over to "sign-off" your computer lab without having to re-issue user passwords.

To Disable the Locked Screen-saver, Perform the following steps:

1. Click on your username at the top right-hand screen
2. Select Settings from the drop-down menu.
3. Click the Power icon located in the Settings Dialog Box
4. Change the amount of time in the Power Saving section to Never or a longer period of time
5. Close the Settings Dialog box.

Part 2: Disable SELinux and Perform Software Updates

SELinux stands for Security-Enhanced Linux. It is a component that helps to better secure the system to protect against intrusion (hackers). SELinux is enabled upon the default install of CentOS. SELinux can be a good thing, if you take care of it and know how it works. For this course it is strongly recommended that you disable SELinux by default because we won't have the time to reconfigure it every time the labs make it necessary.

Perform the following Steps:

1. Disabling SELinux is quite simple.
2. Edit the file /etc/selinux/config
3. In the editing session, set SELINUX to disabled (from targeted) and save your editing session.

Answer Investigation 2 observations (all parts and questions) in your lab log book.

Part 3: Accessing Administrative Privileges

Accessing the Administration Account (root) Many administrative tasks require the root administrative account. There are many ways to access this administration account: Login: root (enter root password) Switch User to root (without login): su: Remains in regular user's directory, does not run root's startup script(s). su - : Changes to root's home directory (/root) and runs root's start script(s).

Navigate through your Graphical CentOS system, locate and run a terminal program (in order to issue Linux commands).

Issue and record the commands used and the output generated in each of the following steps:

1. With older (ancient) versions of Linux, a user once may have been allowed to login to their graphical Linux system using root as their user-name and their root password. This has been determined to be a security risk and that option has been removed with many or all Linux operating systems.
2. Therefore, from this point onwards, you will be logging into your regular user account instead and issuing a command to login as the root user.
3. Refer to the Information box regarding how to access the admin account from the command line.
4. Issue the command su Issue the pwd and whoami commands to confirm your directory pathname. When finished logout of this account.
5. Issue the command su - Issue the pwd and whoami commands to confirm your directory pathname. What do you notice are the main differences between using su versus using su - ?
6. An installation log file called /var/log/anaconda/packaging.log has been created to record the installation of your centos1 machine. This file is an ASCII file which can be viewed with the more command.
7. You can make use of this file to determine how many packages have been installed: complete the following command to count the number of packages that are labelled "Installing" in the installation log file:

grep -i packaging /var/log/anaconda/packaging.log | wc -l

Part 4: Using Shell Scripting to Generate System Information Reports

Bash Shell Scripting Reference Guide: She-bang Line Forces shell script to run in a specific Shell Some shell syntax not backward compatible #! must be at beginning of first line of shell script Example: #!/bin/bash Variables Environment System-wide or "global" variable Usually appear in UPPERCASE letters Can view with command: set | more $ in front to expand variable to value Examples: USER, PATH, HOME, SHELL User-defined Variable created by user (command line, scripting) Examples: myVar="my value"; readonly myVar; export myVar read -p "enter value: " myVar Positional parameters Assign values with set command or shell script arguments These variables are numbered (eg. $1, $2 ... $10} Special parameters: $*, $@, $#, $$, $? Command Substitution Useful method to expand output from a command to be used as an argument for another command. Examples: file $(ls) set $(ls);echo $#;echo $* echo "hostname: $(hostname)" Logic Control Flow Statements $? variable true (0) if command runs; otherwise is false (non-zero) Example: if echo $myVar | grep "match" then echo "Match" fi The test command is used to test conditions. Square brackets [ ] is short-cut for test command (args contained inside with spaces). The exit command can be used to terminate the shell script with a false value. Example: if [ $USER = "root" ] then  echo "You must be root"  exit1 fi For numberic comparison, use the following test options: -gt,-ge, -lt, -le, -eq, -ne Examples: if test $age -gt 65 then  echo "retire" else  echo "don't retire" fi if [ $grade -gt 79 ] then  echo "You get Good Mark" elif [ $grade -gt 49 ] then  echo "You pass" else  echo "You fail" fi For testing for file information, you can use -d to test if directory pathname exists, and -f if the file pathname exists. You can use ! for negation. Examples: if [ -d directory-pathname ] then echo "directory exists" fi if [ ! - f file-pathname ] then echo "File does not exist" fi Loops (iteration): Loops and logic are a very important elements of shell scripting (not to mention programming as well). Determinant loops (such as for loops) usually repeat for a preset number of times (eg. counts, positional parameters stored). In-determinant loops (such as while or until loops) may repeat based on unknown conditions (like waiting for user to enter correct data). Test conditions can be used with in-determinant loops, or even commands! If a command runs successfully (eg ls, cd, grep matching a pattern), zero (true) value is returned, otherwise a non-zero (false) value is returned. Command options or redirection to /dev/null can be used to just test if command runs, but not display stdout or stderr. Conditional statements "and" (&&) / "or" (||) can also be used when testing multiple conditions. Examples (try in a shell script) set ops235 is fun for x do  echo "argument is $x" done for x in $(ls) do  echo "Filename: $x" done read -p "enter a whole number: " num until echo $num | grep -q "^[0-9][0-9]*$" do  read -p "Incorrect. Please enter WHOLE NUMBER: " num done read -p "pick a number between 1 and 10: " num while [ $num -lt 1 ] || [ $num -gt 10 ] do  read -p "Incorrect. Please pick number between 1 and 10: " num done

It is very common for System Administrators to keep records regarding their installed computer systems. For example, it is necessary to have a record of all the hardware information for each machine in order to help fix computer hardware problems, and to assist when purchasing additional consistent computer hardware.

Therefore, it makes sense to also have a record of the installed computer software as well. This can contain information regarding the Linux operating system, installed software, and network connectivity information.

Perform the Following Steps:

1. Study the Linux commands and their purpose to note computer software information for your installed centos1 VM. You should take time to issue each of these commands to view the output, and record this chart in your lab1 logbook.
   
   
2. Login to your centos1 VM, open a Bash Shell terminal, and login as root by issuing the command:
   su -
   
   
3. Make certain to record output from these commands (except for the ps -ef output) in your lab1 logbook.

Command(s)	Purpose
uname -rv hostname ps -ef	Basic Linux OS information such as kernel version, host-name of Linux server, and all processes that are running on the system after installation.
rpm -q -a | wc -l rpm -q -a -l | wc -l rpm -q -l gedit | wc -l	Obtain number of installed packages in the rpm database. Option -q is to "query" informationo, option -a means for all installed packages, option -l means all files installed as opposed to just the application.
ifconfig route -n nslookup	Obtain network connectivity confirmation including: IP ADDRESS, Netmask, routing (default gateway), and the default Domain Name Server.

You may have learned about creating and running Bash Shell Scripts in your ULI101 course. Shell scripts help Linux users and system administrators to automate repetitive tasks to become more efficient and to help them save time. You will be reviewing and building a basic Bash Shell script to generate information reports for your newly-installed Linux host machine.

4. Refer to the Bash Shell Scripting Guide prior to proceeding with this section. As you continue, you are required to make Bash Shell scripting notes in your lab1 logbook.
5. Create a directory called bin in your root home directory to store your shell scripts by issuing the command:
   mkdir ~/bin
6. Change to that newly-created bin directory

NOTE: Although it is possible to copy and paste, is it highly recommended to manually enter the following Bash Shell scripting content to become familiar with writing Bash Shell scripting code. Remember: you will be required to create a Bash Shell script on your final exam, so you need the practice!

7. Launch a text editor (such as vi or nano) to create a Bash Shell script called: myreport.bash in your current directory.
8. Copy and paste the text below into your vi editing session for your file report.bash
   (how do you copy and paste efficiently in Linux?)
   


#!/bin/bash

# Author: *** INSERT YOUR NAME ***
# Date: *** CURRENT DATE ***
#
# Purpose: Creates system info report
#
# USAGE: ./myreport.bash

if [ $USER != "root" ] # only runs if logged in as root
then
 echo "You must be logged in as root." >&2
 exit 1
fi


9. Save your editing session, assign the myreport.bash file read and execute permissions (at least for the owner) and run by typing:
   ./myreport.bash
10. Did it run? If not what do you think you need to do in order to run the Bash Shell Script?
11. Issue the command su - and run the script from the regular user's home directory (not root's home directory):
    ~regularuserid/myreport.bash
12. Did it work?
13. Reopen your text-editing session for ~regularuserid/myreport.bash and add the following lines of code to the bottom of the shell script file:

# Create report title

echo "SYSTEM REPORT" > /root/report.txt
echo "Date: $(date +'%A %B %d, %Y (%H:%M:%p)')" >> /root/report.txt
echo >> /root/report.txt


8. Save and run the bash shell script. View the contents of the file called report.txt that was generated (I hope you are using the up arrow key to issue previously issued commands in order to save time!). Notice how the redirection symbol > is used at the beginning of the report, and then the other redirection symbol >> is used to help "grow" the report with the other content.
9. The only remaining content of the report would be the system information. We can use a shell scripting trick called "command substitution" $( .. ) in order place results from an command to be used by another command (like echo). Re-edit the shell script and add the following code at the bottom of the shell script file:

echo >> /root/report.txt
echo "Hostname: $(hostname)" >> /root/report.txt
echo >> /root/report.txt
echo "Kernel Version: $(uname -rv)" >> /root/report.txt
echo >> /root/report.txt


10. Save, run the script, and view the report.txt contents (are you using tip that was given to save time?).
11. Edit the shell script and include output from the ps aux and ifconfig commands (with appropriate titles). Remember to redirect that output to add to the bottom of the file!
12. Save, run and confirm that the shell script is working correctly.
13. What would be the use of keeping this shell script as a Linux system administrator?

14. Here are some more "complex" Bash Shell scripts, that perform the same task. Although you are not require to understand some of these other tricks, it is recommended that you view the contents of the scripts and save them for future consideration or exmaples.
15. The wget command can be used to quickly download files from the Internet. Issue the following command:
    wget https://scs.senecac.on.ca/~murray.saul/text-report.bash
16. Verify that the file text-report.bash was downloaded to your current directory.
17. Assign read and execute permissions for this file by issuing the command: chmod u+rx text-report.bash
18. Run this Bash Shell script by issuing the command: ./text-report.bash
19. Check to see if it created a report in your current directory. What is the purpose of the report?
20. Use the vi text editor to view the contents of the file text-report.bash. Can you understand how this script works?
    
    
21. Use the wget command to download, study, and run the following shell scripts on-line:

    https://scs.senecac.on.ca/~murray.saul/report.bash
https://scs.senecac.on.ca/~murray.saul/report3.bash

22. Try to understand what these Bash Shell scripts do.
23. You have completed lab1. Proceed to Completing The Lab, and follow the instructions for "lab sign-off".

Answer Investigation 2 observations (all parts and questions) in your lab log book.

LAB 1 SIGN-OFF (SHOW INSTRUCTOR)

Students should be prepared with all required commands (system information) displayed in a terminal (or multiple terminals) prior to calling the instructor for signoff.

Download and Run Lab1 Checking Script & Show Lab1 Work

Shell scripting is so essential for Linux administration that this course has created a shell script for every lab for this course that a student must download and run in order to check their work.

If you have performed the lab correctly, then you will get a series of  OK  messages and you can proceed with the SIGN-OFF for lab1. On the other hand, if there were errors, then a  WARNING  message will appear with general suggestions that you will need to fix on your centos1 VM in order to have your OPS235 sign-off in this lab in order to proceed to the next lab.

You need to show that the downloaded and run lab-checking script displays with all  OKs  and a congratulation message is displayed (along with other required submission requirements) in order to proceed until the next lab.

Perform the Following Steps:

1. Launch your centos1 VM, open the Bash Shell terminal and issue the command: su - and enter root's password.
   
   
2. Make a directory called /root/bin where you will be storing your shell scripts.
   
   
3. Change to the /root/bin directory.
   
   
4. Issue the Linux command:
   wget http://matrix.senecac.on.ca/~murray.saul/ops235/lab1-check.bash
   
   
5. Give the lab1-check.bash file execute permissions (for the file owner).
   
   
6. Run the shell script and if any warnings, make fixes and re-run shell script until you receive "congratulations" message.
   
   
7. Arrange evidence (command output) for each of these items on your screen, then ask your instructor to review them and sign off on the lab's completion:

✓ Output of lsblk command showing correct partition names and sizes

✓ Output from running the lab1-check.bash script with all  OK  messages

✓ Lab1 logbook containing the values for:

• IP address, MAC address, Default route (gateway) and
  DNS name server IP Address

✓ lab2 logbook with first column of Comparison Chart for centos1 VM.

Practice For Quizzes, Tests, Midterm & Final Exam

1. Define the term Virtual Machine..
2. List 5 reasons for using virtual machines.
3. List the major screens (steps) in the installation of Centos7 full install DVD.
4. What key-combination is used to toggle the view of your running VM from "window-mode" to "full-screen-mode"?
5. List the steps for disabling SELinux.
6. List the steps for backing up your VM image from a computer to a USB key.
7. Why to you need to backup VM image to USB prior to leaving Seneca's lab?
8. List the steps for restoring your VM image to a computer from a USB key.
9. Write the Linux command to download the on-line file: http://linux.server.org/package.tar.gz