[one-users] KVM snapshots

[Tobias Brunner]

Hi,

> Well, can you do it manually on the same configuration? It should be
> easy to verify.

I've tried to do it manually:

# virsh snapshot-create one-5
error: unsupported configuration: internal checkpoints require at least 
one disk to be selected for snapshot

Asking the libvirt ML leads to this answer:

> An internal snapshot of a VM requires that the VM has at least one disk
> using a QCOW2 volume or similar. The memory state is saved in that
> image. Your VM has only a RAW disk image and thus it can't be used for
> internal snapshot.
> 
> You can either use an external snapshot (the memory image is stored
> separately), but the support for external snapshots isn't finished yet
> (they can't be reverted automatically).
> 
> The second option is to convert your VM to a qcow2 image file..

And later:

>> How can I create an external snapshot?
> Add '--disk-only' for an offline domain, or use 'virsh
> snapshot-create-as --memspec' instead of 'snapshot-create' for an 
> online
> guest (you can also use snapshot-create for an external snapshot, but
> you have to write appropriate XML for the case, rather than relying on
> the no-arg option that provides a default XML for an internal snapshot;
> so I find snapshot-create-as a lot easier to work with).
> 
> Internal snapshots require qcow2 (or the less-used qed) file format,
> full stop.  If you want your snapshots to live on RBD storage backend,
> then you either layer the qcow2 file on top of that backend, or you use
> external snapshots.

Some system information:
* Ubuntu 13.04 64Bit
* virsh --version: 1.0.2
* OpenNebula version 4.2
* The XML of the VM is below

Does anyone have snapshots running using RBD?

Cheers,
Tobias


<domain type='kvm' id='4'>
    <name>one-5</name>
    <uuid>cff38c6a-2996-7709-c4f4-0ed826c2fb02</uuid>
    <memory unit='KiB'>524288</memory>
    <currentMemory unit='KiB'>524288</currentMemory>
    <vcpu placement='static'>1</vcpu>
    <cputune>
      <shares>1024</shares>
    </cputune>
    <os>
      <type arch='x86_64' machine='pc-i440fx-1.4'>hvm</type>
      <boot dev='hd'/>
    </os>
    <features>
      <acpi/>
    </features>
    <clock offset='utc'/>
    <on_poweroff>destroy</on_poweroff>
    <on_reboot>restart</on_reboot>
    <on_crash>destroy</on_crash>
    <devices>
      <emulator>/usr/bin/kvm</emulator>
      <disk type='network' device='disk'>
        <driver name='qemu' type='raw' cache='none'/>
        <source protocol='rbd' name='one/one-5-5-0'/>
        <target dev='hda' bus='ide'/>
        <alias name='ide0-0-0'/>
        <address type='drive' controller='0' bus='0' target='0' 
unit='0'/>
      </disk>
      <disk type='file' device='cdrom'>
        <driver name='qemu' type='raw'/>
        <source file='/var/lib/one//datastores/0/5/disk.1'/>
        <target dev='hdb' bus='ide'/>
        <readonly/>
        <alias name='ide0-0-1'/>
        <address type='drive' controller='0' bus='0' target='0' 
unit='1'/>
      </disk>
      <controller type='ide' index='0'>
        <alias name='ide0'/>
        <address type='pci' domain='0x0000' bus='0x00' slot='0x01'
function='0x1'/>
      </controller>
      <controller type='usb' index='0'>
        <alias name='usb0'/>
        <address type='pci' domain='0x0000' bus='0x00' slot='0x01'
function='0x2'/>
      </controller>
      <interface type='bridge'>
        <mac address='02:00:c0:a8:31:97'/>
        <source bridge='vmbr0'/>
        <virtualport type='openvswitch'>
          <parameters 
interfaceid='6e492227-cd8b-f472-9f3d-1161ddf9ecfc'/>
        </virtualport>
        <target dev='vnet0'/>
        <alias name='net0'/>
        <address type='pci' domain='0x0000' bus='0x00' slot='0x03'
function='0x0'/>
      </interface>
      <input type='mouse' bus='ps2'/>
      <graphics type='vnc' port='5905' autoport='no' listen='0.0.0.0'>
        <listen type='address' address='0.0.0.0'/>
      </graphics>
      <video>
        <model type='cirrus' vram='9216' heads='1'/>
        <alias name='video0'/>
        <address type='pci' domain='0x0000' bus='0x00' slot='0x02'
function='0x0'/>
      </video>
      <memballoon model='virtio'>
        <alias name='balloon0'/>
        <address type='pci' domain='0x0000' bus='0x00' slot='0x04'
function='0x0'/>
      </memballoon>
    </devices>
    <seclabel type='dynamic' model='apparmor' relabel='yes'>
      <label>libvirt-cff38c6a-2996-7709-c4f4-0ed826c2fb02</label>

<imagelabel>libvirt-cff38c6a-2996-7709-c4f4-0ed826c2fb02</imagelabel>
    </seclabel>
</domain>