Manage KVM Using CLI on CentOS /RHEL

This tutorial discusses how to manage KVM using CLI with the help of a utility called 'virsh'. In our last tutorial, we learned to install hardware based virtualization software named KVM and also created a Virtual machine in KVM using its graphical tool called virt-manager. We will learn to create new VM with ‘virt-install’ & managing KVM based Virtual machines in CLI using command-line tool named ‘virsh’.

Firstly, we will create a new Virtual machine using ‘virt-install’,

Creating a new virtual machine

Virt-install is a command-line tool used to create KVM based virtual machines. To create a new virtual machine, run the following command

Here virt-install is the command to create a new VM,

--name is the name of VM,

--disk path , is the storage path for VM,

--graphics, is the way to connect to VM (usually its spice),

--vcpu, number of CPUs for the VM,

--ram, is amount of memory for VM,

--location, the source path of installation ISO,

--network, is the bridge adapter to be used by VM>

After successful execution of this command, a new window (virt-viewer popup window) will launch where you can communicate with your VM & continue the installation of OS on KVM.

Managing KVM

Now that the machine has been created, we will learn managing KVM based VMs via CLI using ‘virsh’. Virsh supports a large number of commands, to view all of them use

& you  will have all the commands that can be used with visrsh. Some the important commands are listed here in tutorial as well.

Listing all VMs

To list all VMs that have been installed under KVM, use the following command,

Id    Name                           State

----------------------------------------------------

1     ltechlab                       running

2     win7                             running

Starting a VM

To start a VM, run the following commands,

Where VM name , in our case, can be ltechlab or win7.

Shutting a VM

For shutting down a VM, run the following

This will shutdown VM in an orderly manner. To instantly shut down a VM, run the following

It will stop VM instantly & might cause damage to VM.

Rebooting a VM

For rebooting VM, run

Suspending a VM

For suspending a VM, the command is

Resuming a VM

For resuming a VM, the command is

Note:- If the host is rebooted, the suspended state of the VM will be lost.

Saving a System State

To save the current state of a VM, run the following

Where/data/vm is the destination where the state of the VM will be saved.

Restoring the state of a VM

A saved state of the VM can be restored using the following command

A saved state can be restored even after a host system reboot.

Connecting to VM console

To exit out of the console. Press ’ctrl+j’.

Displaying VM information

To display complete VM information, run the following command

Displaying VM memory & CPU usage

To see the memory & CPU being used by VM, run

Guys these were some commands that are used to manage KVM using CLI in CentOS. If having any doubts or queries, please use the comment box down below & we will surely get back to you.