Virtual Server Snapshots

A Snapshot is a local backup of a virtual server disk. A snapshot does not take up any disk capacity at the time of creation. The disk capacity is consumed only by changes performed on the disk after the snapshot’s creation.

../../_images/vm_snapshot_list.png
Access Permissions  
SuperAdmin read-write
DCAdmin read-write
VmOwner read-write

Note

Creating a snapshot and performing a rollback are instant operations. It is recommended to create a snapshot before performing any non-trivial action inside the virtual server.

Warning

Snapshots are stored on the same node storage as virtual server disks used for the snapshots. Failure of a node storage, therefore, results in loss of snapshots.

Snapshot Parameters

  • Name - Snapshot name (read-only).

  • Disk ID - Virtual server disk ID (read-only).

  • Type - Snapshot type (read-only). One of:

    • Manual
    • Automatic
  • Created - The date and time when the snapshot was created (read-only).

  • Status - Snapshot state (read-only). One of:

    • ok
    • pending
    • rollback
    • lost
  • Size - The approximate size of the snapshot (read-only).

  • Note

Note

The snapshot size parameter is automatically updated once every hour.

Note

Snapshots created with the Freeze filesystem option enabled are marked with a flag icon appended to their status.

Advanced Snapshot Parameters

  • Freeze filesystem? - Whether to create an application-consistent snapshot (KVM only). Requires QEMU Guest Agent to be running inside the virtual server.

Snapshot Actions

  • Create snapshot - Immediately create a snapshot from one or all virtual server’s disks.

    ../../_images/vm_create_snapshot.png
  • Delete snapshot - Remove data of the snapshot.

    ../../_images/vm_manage_snapshot.png
  • Rollback snapshot - Restore server disk data from the snapshot.

    Warning

    A snapshot rollback will lead to deletion of all data including every newer snapshot created after the restored snapshot.

    Note

    It is also possible to restore a snapshot into another virtual server. This functionality is currently available only in the API (PUT /vm/(hostname_or_uuid)/snapshot/(snapname)) .

Snapshot Definitions

A Snapshot Definition is a configuration based on which periodic snapshots are automatically created and deleted.

../../_images/vm_snapshot_definition.png
Access Permissions  
SuperAdmin read-write
DCAdmin read-write
VmOwner read-only

Snapshot Definition Parameters

../../_images/vm_snapshot_add_definition.png
  • Name - Snapshot definition name.
  • Disk ID - Virtual server disk ID.
  • Schedule - Automatic scheduler configuration in Cron format. Use your local time for the hour field (it will be internally converted into UTC).
  • Retention - Maximum number of snapshots to keep. After exceeding this number of snapshots, the oldest snapshot associated with the snapshot definition will be automatically removed.
  • Active - Whether the snapshot definition is active.
  • Description

Advanced Snapshot Definition Parameters

  • Freeze filesystem? - Whether to create application-consistent snapshots (KVM only). Requires QEMU Guest Agent to be running inside the virtual server.

Cron Format

Cron format is a flexible way to define time and frequency of running a periodic task. It is defined as a string of five fields separated by a space.

Field name Allowed values
Minutes 0-59
Hours 0-23
Day of month 1-31
Month 1-12 (January - December)
Day of week 0-6 (Sunday - Saturday)

Examples

  • 30 08 10 06 * - Run a task once every year on June 10 at 8:30 AM.
  • 00 11,16 * * * - Run a task twice a day at 11:00 AM and 4:00 PM.
  • 00 09-17 * * * - Run a task once every hour between 9:00 AM and 5:00 PM.
  • 00 09-18 * * 1-5 - Run a task once every hour between 9:00 AM and 5:00 PM from Monday till Friday.
  • * * * * * - Run a task once every minute.
  • 0,10,20,30,40,50 * * * * - Run a task once every 10 minutes.
  • 0,2,4,6,8,10 * * * * - Run a task every 2 minutes during the first 10 minutes of a hour.
  • 0 0 1 1 * - Run a task once a year at midnight of January 1.
  • 0 0 * * * - Run a task once a day at midnight.
  • 0 * * * * - Run a task once an hour at the beginning of the hour.

Creating an Image From a Snapshot

../../_images/add_vm_image.png
  • Name - Unique image identifier (usually used in the API).

  • Alias - A user-defined name of an image (usually displayed in the GUI).

  • Version - Image version.

  • Access - Image visibility. One of:

    • Public - Image is usable by all users in this virtual data center.
    • Private - Image is usable by SuperAdmins and owners of this image.
    • Deleted - Image is hidden and unusable for new servers, but can be still used by some already defined servers.
  • Owner - Image owner.

  • Tags - Comma-separated list of image tags, which will be inherited by virtual servers that will use this image.

  • Resizable? (Resize) - Specifies whether an image is able to resize a virtual disk during an initial start or deploy procedure. This is usually achieved by a post-installation script that has to be included in the disk image.

  • Shutdown after deploy? (Deploy) - Specifies whether an image is able to shut down a virtual server after an initial start. Such an image should include a post-installation script, which will shut down the running operating system after it has been successfully configured. After a virtual server is stopped, it is considered to be successfully deployed, and it will be automatically started by the system.

  • Description

See also

More information about disk images can be found in a separate chapter.