Virtual Machines

Virtual machines can be created to a certain specification or cloned from an existing template in the virtual machine pools. For more information, see Creating a New Virtual Machine and Creating a Template in the Oracle Linux Virtualization Manager: Administration Guide. You can also import an Open Virtual Appliance (OVA) file into your environment from any host in the data center. For more information, see oVirt Virtual Machine Management Guide in oVirt Documentation.

  • A virtual machine pool is a group of on-demand virtual machines that are all clones of the same template. They are available to any user in a given group.

    When accessed from the VM Portal, virtual machines in a pool are stateless, meaning that data is not persistent across reboots. Each virtual machine in a pool uses the same backing read-only image, and uses a temporary copy-on-write image to hold changed and newly generated data. Each time a virtual machine is assigned from a pool, it is allocated in its base state. Users who have been granted permission to access and use virtual machines from a pool receive an available virtual machine based on their position in a queue of requests.

    When accessed from the Administration Portal, virtual machines in a pool are not stateless so that administrators can make changes to the disk if needed.

  • Guest agents and drivers provide functionality for virtual machines such as the ability to monitor resource usage, shutdown and reboot the virtual machines from the Administration Portal.

    Important:

    See Windows Virtual Machines Lose Functionality Due To Deprecated Guest Agent in the Known Issues section of the Oracle Linux Virtualization Manager: Release Notes.
  • A snapshot captures a virtual machine's operating system and applications on all available disks at a given point in time. Use a snapshot to restore a virtual machine to its previous state. For more information, see

  • A template is a copy of a virtual machine that you can use to simplify the subsequent, repeated creation of similar virtual machines. Templates capture the configuration of software, the configuration of hardware, and the software installed on the virtual machine on which the template is based, which is known as the source virtual machine.

    Virtual machines that are created based on a template use the same NIC type and driver as the original virtual machine but are assigned separate, unique MAC addresses.

Considerations When Using Snapshots

A snapshot is a picture of a virtual machine's state and should not be uses a primary backup process. You take snapshots so you can revert the virtual machine to a specific point if and when required. Before creating snapshots, consider the following:

  • Do not shutdown or start a virtual machine that displays an illegal status in the Administration Portal as this might cause data corruption or the virtual machine might fail to start.
  • As soon as you revert to a snapshot and it is no longer required, delete the snapshot.
  • Taking several snapshots in a row without any cleanup can affect virtual machine and host performance.
  • When taking a snapshot, it creates a new copy of the virtual machine disk; so the more data you write to the snapshot, the longer it takes when using it.
  • For an I/O intensive virtual machine, when deleting a snapshot remove it while the virtual machine is shut down (cold merge) instead of deleting the snapshot while the virtual machine is up (live merge).
  • Ensure you have installed the latest guest agent package on your virtual machine before taking snapshots.

Virtual Machine Consoles

You access virtual machine consoles using the Remote Viewer application (virt-viewer) on Enterprise Linux and Microsoft Windows clients. Remote Viewer allows you to interact with a virtual machine in a similar way to a physical machine. For more information, see Consoles.

To download Remote Viewer, see Installing a Remote Viewer on Client Machine in the Oracle Linux Virtualization Manager: Administration. You must have Administrator privileges to install the Remote Viewer application.