Linux KVM Virtualization Guest Operations

Internal

• Linux Virtualization Operations

List Available Guests

virsh list [--all]

Information about a Guest

Guest Configuration

The following command provides details, about:

• the amount of virtual memory and virtual CPU allocated to the guest.
• guest disk devices, their type (qcow, raw, etc.), their mapping on external storage volumes, etc.
• guest network devices.
• etc.

 virsh dumpxml <guest-name>

Filesystems

virt-filesystems --all -lh -d <guest-name>

Running State of a Guest

virsh domstate

Start/Stop Guest Virtual Machines

virsh start [--console] <vm-name>

Graceful shutdown:

virsh shutdown <vm-name>

Ungraceful shutdown:

virsh destroy <vm-name>

This command does an immediate ungraceful shutdown and stops the specified guest. Using virsh destroy can corrupt guest file systems. Use the destroy option only when the guest is unresponsive.

Connect to the Guest Virtual Machine

virsh console

Create a Guest Virtual Machine

Virtualization host storage and host-level networking must be configured as a prerequisite to creating guest virtual machines. Once storage pools and storage volumes are made available, and the networking is configured, guest virtual machines can be created with

virt-install

The guest ("domain") name may contain dot, so we can simulate a hierarchy ("ose36.master", or "environment-name.host-in-environment-name").

If the XML definition of a virtual machine is available, it can be created with:

virsh define

Add Storage to Guests

Adding Storage to Guests

Reconfigure Guest Memory

Reconfigure Guest Memory

Cloning and Snapshotting

Clone a Guest Virtual Machine

The goal of a cloning operation is to create an entirely new guest, based on the configuration of an existing guest. Entirely new storage must be provisioned during the cloning operation, and the O/S image must be transferred on the new storage and updated as described below. Also, care should be taken to avoid conflict while accessing shared resources - memory, CPUs, network devices.

Cloning a Guest Virtual Machine

Snapshot a Guest Virtual Machine

The goal of a snapshotting operation is to preserve the state of the guest, at a certain moment in time, so it can be reverted to, later, possibly after the guest was removed for a while from the virtualization host. For more theoretical considerations concerning guest snapshots, see "Linux Virtualization Concepts - KVM Virtual Machine Snapshot".

• Manual Low-Level Guest Export/Import Procedure
• Guest Snapshot Using virsh snapshot Functionality

Remove a Guest

virsh undefine <guest-name> [--remove-all-storage]