In the previous guide, we looked at how to install the KVM hypervisor on Rocky Linux / AlmaLinux. We went further and demonstrated how you can create and manage virtual machines using the virt-manager. This is a desktop application that provides a GUI interface that allows users to intuitively create and manage virtual machines.
In this guide, we shift focus slightly and walk you through how you can create a virtual machine on command line.
For this to be successful, you need to have KVM installed on your Linux instance. We already have a guide on how to install KVM on Rocky Linux / AlmaLinux.
Additionally, ensure that you have a sudo user configured on your system for performing elevated tasks.
How to create a virtual machine in KVM on Command line
In this example, we are going to create a virtual machine from a Debian 10 ISO image located in the ‘Downloads’ folder in the home directory. To achieve this, launch the terminal and execute the following command:
$ sudo virt-install --name=debian-10 \ --os-type=Linux \ --os-variant=debian10 \ --vcpu=2 \ --ram=2048 \ --disk path=/var/lib/libvirt/images/debian.img,size=15 \ --graphics vnc,listen=0.0.0.0 \ --location=/home/james/Downloads/debian-10.1.0-amd64-netinst.iso \ --network bridge:virbr0
Let’s briefly expound on the options used:
–name : This is the name of the virtual machine, in our case – debian-10.
–os-type: The option indicates the operating system.
–os-variant: This indicates the flavor or version of your OS. You can get a comprehensive list of all he supported OS variants by running the osinfo-query os command.
–vcpu: The number of virtual CPUs allocated to the virtual machine.
–ram: The amount of RAM in Megabytes allocated to the virtual machine.
–disk path: The option specifies the path of the virtual machine image. The size option specifies the size of the image in GB.
–graphics: This specifies the graphical mode used to access the virtual machine. In this case, we have specified vnc as our preferred option.
–location: This points to the location of the ISO image used for creating the virtual machine.
Here is some output generated from running the command:
At this point, the virtual machine is running. But how do you access its graphical interface? There are two main ways of going about this. You can use a VNC client or simply use the Virtual machine manager.
To use VNC, you need to install a VNC client such as TigerVNC. To install it, simply run the command:
$ sudo dnf install tigervnc
Next, run the following command to find out which vnc port the virtual machine is listening to:
$ sudo virsh vncdisplay debian-10
Next, use the application manager to launch TigerVNC.Type in your IP address followed by the port.
This opens the TigerVNC graphical viewer as shown.
The virsh utility is a command-line tool that is used to manage virtual machines. You can perform various operations as we shall see shortly.
To list currently running virtual machines, run the command:
$ sudo virsh list
To list all the virtual machines, including those that have been powered off use the –all option at the end. Since we have only deployed a since VM, the output will remain the same.
$ sudo virsh list --all
To poweroff a vm, use the syntax:
$ sudo virsh shutdown vm
For example, to poweroff the virtual machine, run:
$ sudo virsh shutdown debian-10
To start the virtual machine execute:
$ sudo virsh start debian-10
To reboot the virtual machine, run:
$ sudo virsh reboot debian-10
To suspend the VM, run the command:
$ sudo virsh suspend debian-10
To resume the vm, execute:
$ sudo virsh resume debian-10
And finally, you can delete to destroy the virtual machine:
$ sudo virsh destroy debian-10
In this guide, we have shown you how to create and manage guest virtual machines on KVM from the command-line. We hope you have grasped the basic concepts of creating anf managing the state of virtual machines straight from the terminal console.
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