OPS245 Scripting Exercises Lab 2 dev

Virtual Machine Backup Script

Overview

In Lab 2 Investigation 3 you performed a manual backup of all 3 virtual machines. While this is something both important and necessary, it's a tedious process. This is something you could automate through scripting. In this exercise you are going to write a script that will back up all three of your virtual machines. We will improve on this backup script in a later exercise. To begin, open your text editor (vi) on c7host and copy the following template in. Be sure to modify Author and Date with the correct information.

#!/usr/bin/env python3
# Author: Your Name; youremail@myseneca.ca
# Date:
# Purpose: Backs up virtual Machines
# Usage: ./backupVM.py
#

# Import the Operating System (os) module, Subprocess module and Sys module


# Store the output of the whoami command as a variable called whoami


# Check the current user (who is executing the script) and store the information in the variable currentuser.  The os.geteuid() command requests the current user ID from the operating system.  Root has a UID of (0).  Users have non-zero values, usually starting at 1000.  We can use this to check if the current user is root or not.


# Using an if statement check if currentuser is not equal to 0


	# Print a message telling the user who they are.  Use , to concatenate (join) the message and the whoami variable
	

	# Exit with an error message indicating they must be root
	

# Else (they are root, we can continue)


	# Prompt the user asking if they wish to back all VMs, accepting options y for yes or n for no.  Store the answer in the variable backupAll
	

	# If backupAll equals "n"
	
		
		# Prompt the user asking which VM they wish to backup.  Store the answer in the variable backupVM
		
		
		# If backupVM equals "centos1"
		

			# Print "Backing up centos1"
			

			# Use os.system to call the virsh dumpxml command you used for centos1 in Lab 2 Investigation 3
			

			# Use os.system to compress (using gzip) the .qcow2 for centos1, using the same syntax as in Lab 2 Investigation 3
			

		# Else if (elif) backupVM equals "centos2"
		

			# Print "Backing up centos2"
			

			# Use os.system to call the virsh dumpxml command you used for centos2 in Lab 2 Investigation 3
			

			# Use os.system to compress (using gzip) the .qcow2 for centos2, using the same syntax as in Lab 2 Investigation 3
			

		# Else if (elif) backupVM equals "centos3"
		

			# Print "Backing up centos2"
			

			# Use os.system to call the virsh dumpxml command you used for centos3 in Lab 2 Investigation 3
			

			# Use os.system to compress (using gzip) the .qcow2 for centos3, using the same syntax as in Lab 2 Investigation 3
			

		# Else, user has entered an invalid choice
		
			
			# Display a message indicating an invalid choice has been made and give the valid options (centos1, centos2, centos3) and exit
			

	# Else, we're doing a full backup (backing up all 3 virtual machines: centos1, centos2, centos3)
	

		# Print "Backing up centos1"
		

		# Use os.system to call the virsh dumpxml command you used for centos1 in Lab 2 Investigation 3
		

		# Use os.system to compress (using gzip) the .qcow2 for centos1, using the same syntax as in Lab 2 Investigation 3
		

		# Print "Backing up centos2"
		

		# Use os.system to call the virsh dumpxml command you used for centos2 in Lab 2 Investigation 3
		

		# Use os.system to compress (using gzip) the .qcow2 for centos2, using the same syntax as in Lab 2 Investigation 3
		
			
		# Print "Backing up centos3"
		

		# Use os.system to call the virsh dumpxml command you used for centos3 in Lab 2 Investigation 3
		

		# Use os.system to compress (using gzip) the .qcow2 for centos2, using the same syntax as in Lab 2 Investigation 3
		

		# Exit successfully
		

Filling in the code

The below instructions provide all (or most) of the required code for filling in the above template. Fill in each section in sequence under the appropriate comment block.

Importing the required modules

For this script we will require the following modules:

• os
• system
• sys

Using the import statement (like we have done previously), import the above modules on one line.

import os, system, sys

Storing the output of the current user and checking to see if they are root.

We will use this to indicate an error if the script is not being run as root (without sudo). Create a variable called "whoami" and store the output of the whoami command in it. We will use the subprocess module, with the check_output function to accomplish this task.

whoami = subprocess.check_output("whoami").decode("utf-8")

Check the current user (who is executing the script) and store the information in the variable "currentuser".

We will use the os.geteuid() function for this task. Linux UID's (User IDs) start at 1000 for users. Root has a UID of 0.

currentuser = os.geteuid()