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Department of Computer Science

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Running Virtual Machine via KVM on CS Machines

Running Virtual Machine via KVM on CS Machines

by Hanz Makmur – Oct 04, 2021

To enable users to learn how to setup, manage his/her own operating system, we have enabled KVM (Kernel-based Virtual Machine) software on all CS Desktop Machines.(not servers). This instruction will guide you on how to set you VM using KVM.

Set up Your First Virtual Machine using KVM

To setup your virtual machine using KVM, login with a graphical user interface (GUI). This can be done by logging in front of the machine, WebLogin, X2Go or Windows Remote Desktop.

Running Virt-Manager

Once you are on a GUI based session, open a terminal window and type:  virt-manager  virt-manager is the virtual machine manager used to control virtual machines runs under KVM.

Note: If this is your first time running virt-manager, by default it will look at existing system VMs and will open a dialog box saying  “unable to connect to qemu://system” as displayed below.  You can ignore this message safely and click on  button.

unable to connect to qemu://system

Add  a Connection for User Session 

By default, KVM runs in restricted space. On all CS iLab machines, we have enabled access so users can run KVM in user space. This change requires user to tell KVM to watch for user space connection.

To create a Connection for User session,  pull down menu and select , choose  in the list.

Add a Connection


QEMU/KVM user session

Note: You will get a warning saying “QEMU usermode is not the virt-manager default…” You can safely ignore this and click on button.

This only needs to be done the first time you use virt-manager.

Setting up a New Virtual Machine

To setup a VM, follow steps below. It is a bit complicated but so it is detailed below.

Step 1. Creating a New Virtual Machine.

To setup a new virtual machine, pull down menu and select menu.

New Virtual Machine menu

Step 2. Tell KVM your Media Option

  Pick Local install media (the default) and click  button

Local Install menu

Step 3. Tell KVM Location of your CDROM ISO file

In the field for CDROM install media, click on button which will open up Choose Storage Volume window.

Step 4. Choose your  ISO.

At the bottom of Choose Storage Volume, click  button.


At the top, in the bar where it shows the directory, For this example, we will use Ubuntu 20.04. Click on the ,then click , then click then click and select  and click on the  button.  Ubuntu 20 should now show in the CDROM file as shown below. Click button to continue.

Step 5. Adjust Memory and CPU Settings.

Set the memory for your VM  to MB (8GB)  and CPU to , you can  increase to  16 if you are in iLabU 1- 4 which has more memory. Click button to continue .

Memory and CPU SettingDisk Storage Setting

Step 6. Set your disk size

Set your disk size to . This will give you about 16GB of disk space to play with after the OS is installed.  If you need a bigger storage,  you’ll want to create custom storage in /common/users/your_netid.

click   and button to continue.

Step 7. Installing Ubuntu.

Virt-Manager will  now setup your VM and run it. A screen where you can install Ubuntu will show up. You’ll want to expand the size of that window to see it better. At this point you can go through a normal Ubuntu install. Take the defaults unless you know what part of the OS you want to customize.

Step 8. Remove virtual CDROM image before rebooting.

When the install is finished, before you click you need to remove the virtual CDROM, or it will boot back into the install screen.

At the top of the KVM window, pick and then as shown below.

View Details Menu
A detail window will open. In the left margin, you’ll find . Choose it with the mouse and clear the source path by clicking on the backspace icon next to the ISO path as shown below then click the button. Clear ISO path

Step 9. Reboot the VM.

Now you can pull down menu and select and let the machine reboot
It will tell you to remove the CDROM and hit . You’ve already removed the cdrom, so hit key on your keyboard.

Upon Reboot, you have your own copy of Ubuntu where you can become root.

Exiting Virt-Manager

When you finish using your virtual machine, please shutdown the machine first.  To exit Pull down Virtual Machine menu, choose and then select If the VM hung, you need to to fully shutdown your VM totally.

Running Your VM

When you want to use the VM system again, open a terminal window and type:  virt-manager. Click on virtual machine you want to run in the menu. Once the console opens, Click on  icon on the bar above the window  to start it.

Important Notes:

  • Please shutdown the machine when you’re not using it.
    To shutdown, pull down  menu, choose and then select . If the VM hung, you need to to fully shutdown your VM.
  • A default VM install goes in .local/share/libvirt/images This can grow. When you create the VM it asks you how big a virtual disk you want. The default is 25 GB. It doesn’t use up your quota until space is actually used inside the VM.
  • On the desktop systems, please don’t allocate more than 8 GB of memory. If you use iLabU1 – iLabU4 you can use a larger VM, but 16GB should be enough for anything you’re likely to do.
  • These VMs can use the internet, but you can’t contact them from the internet. That is, you couldn’t run a web server and have someone from outside contact it.
  • It’s very important to shut down your VM when you’re not using it. We can’t survive a situation where our users all leave VMs running thus we Enforced Limitations on CS Machines.