Feature pages are design documents that developers have created while collaborating on oVirt.

Most of them areoutdated, but provide historical design context.

They arenotuser documentation and should not be treated as such.

Documentation is available here.

Hot Plug Disk

Summary

Allow hot addition and removal of virtio-blk and virtio-scsi disks to a running guest.

Owner

  • Michael Kublin
  • Email: mkublin@redhat.com

Current status

Supported since oVirt 3.1. VirtIO-SCSI support added in oVirt 3.3.

Detailed Description

The following feature will allow to hot plug/unplug disks to a running VM. Note that this feature will require the guest’s cooperation, so it will be restricted to operating systems that support it, e.g.m RHEL 5 and above, Windows Server 2003 and above, etc.

User Experience

The following UI mockup contain guidelines for VMs->Disks sub-tab:

User work-flows

New actions will allow the user to plug or unplug a disk to/from a running VM in 3.1 clusters and above.

HotPlug will be allowed only on:

  1. The guest OS supports the operation
  2. VirtIO/VirtIO-SCSI disk
  3. Disk should be unplugged
  4. VM should be up

HotUnPlug will be allowed in the following cases:

  1. The guest OS supports the operation
  2. VirtIO/VirtIO-SCSI disk
  3. Disk should be plugged
  4. VM should be up

In order to perform this operation new verbs will be added to the VDSM side - hotplugDisk and hotunplugDisk (see VDSM’s schema for the full details).

New vdsm errors will be added - HotplugDiskFailed (45) and HotunplugDiskFailed (46). Note that unplugged disks will not be passed to the createVM operation.