OVF converter

Using ovfconverter from the tools directory, one can easily convert previously exported Ganeti instance into OVF package, supported by VMWare, VirtualBox and some other virtualization software. It is also possible to use instance exported from such a tool and convert it to Ganeti config file, used by gnt-backup import command.

For the internal design of the converter and more detailed description, including listing of available command line options, please refer to Ganeti Instance Import/Export using Open Virtualization Format

As the amount of Ganeti-specific details, that need to be provided in order to import an external instance, is rather large, we will present here some examples of importing instances from different sources. It is also worth noting that there are some limitations regarding support for different hardware.

Limitations on import

Network

Available modes for the network include bridged and routed. There is no NIC mode, which is typically used e.g. by VirtualBox. For most usecases this should not be of any effect, since if NetworkSection contains any networks which are not discovered as bridged or routed, the network mode is assigned automatically, using Ganeti’s cluster defaults.

Backend

The only values that are taken into account regarding Virtual Hardware (described in VirtualHardwareSection of the .ovf file) are:

• number of virtual CPUs
• RAM memory
• hard disks
• networks

Neither USB nor CD-ROM drive are used in Ganeti. We decided to simply ignore unused elements of this section, so their presence won’t raise any warnings.

Operating System

List of operating systems available on a cluster is viewable using gnt-os list command. When importing from external source, providing OS type in a command line (--os-type=...) is required. This is because even if the type is given in OVF description, it is not detailed enough for Ganeti to know which os-specific scripts to use. Please note, that instance containing disks may only be imported using OS script that supports raw disk images.

References

Files listed in ovf:References section cannot be hyperlinks.

Limitations on export

Disk content

Most Ganeti instances do not contain grub. This results in some problems when importing to virtualization software that does expect it. Examples of such software include VirtualBox and VMWare.

To avoid trouble, please install grub inside the instance before exporting it.

Import to VirtualBox

format option should be set to vmdk in order for instance to be importable by VirtualBox.

Tests using existing versions of VirtualBox (3.16) suggest, that VirtualBox does not support disk compression or OVA packaging. In future versions this might change.

Import to VMWare

Importing Ganeti instance to VMWare was tested using ovftool.

format option should be set to vmdk in order for instance to be importable by VMWare.

Presence of Ganeti section does seem to cause some problems and therefore it is recommended to use --external option on export.

Import of compressed disks generated by ovfconverter was impossible in current version of ovftool (2.1.0). This seems to be related to old vmdk version. Since the conversion to vmdk format is done using qemu-img, it is possible and in fact expected, that future versions of the latter tool will resolve this problem.

Import examples

Ganeti’s OVF

If you are importing instance created using ovfconverter export – you most probably will not have to provide any additional information. In that case, the following is all you need (unless you wish to change some configuration options):

ovfconverter import ganeti.ovf
[...]
gnt-instance import -n <node> <instance name>

Virtualbox, VMWare and other external sources

In case of importing from external source, you will most likely have to provide the following details:

• os-type can be any operating system listed on gnt-os list
• name that has to be resolvable, as it will be used as instance name (even if your external instance has a name, it most probably is not resolvable to an IP address)

These are not the only options, but the recommended ones. For the complete list of available options please refer to Command Line description <design-ovf-support.rst>

Minimalistic but complete example of importing Virtualbox’s OVF instance may look like:

ovfconverter virtualbox.ovf --os-type=lenny-image \
  --name=xen.test.i1 --disk-template=diskless
[...]
gnt-instance import -n node1.xen xen.test.i1

Export example

Exporting instance into .ovf format is pretty streightforward and requires little - if any - explanation. The only compulsory detail is the required disk format, provided using the --format option.

Export to another Ganeti instance

If for some reason it is convenient for you to use ovfconverter to move instance between clusters (e.g. because of the disk compression), the complete example of export may look like this:

gnt-backup export -n node1.xen xen.test.i1
[...]
ovfconverter export --format=vmdk --ova \
  /srv/ganeti/export/xen.i1.node1.xen/config.ini
[...]

The result is then in /srv/ganeti/export/xen.i1.node1.xen/xen.test.i1.ova

Export to Virtualbox/VMWare/other external tool

Typically, when exporting to external tool we do not want Ganeti-specific configuration to be saved. In that case, simply use the --external option:

gnt-backup export -n node1.xen xen.test.i1
[...]
ovfconverter export --external --output-dir ~/ganeti-instance/ \
  /srv/ganeti/export/xen.i1.node1.xen/config.ini

Known issues

Conversion errors

If you are encountering trouble when converting the disk, please ensure that you have newest qemu-img version.

OVA and compression

The compressed disks and OVA packaging do not work correctly in either VirtualBox (old version) or VMWare.

VirtualBox (3.16 OSE) does not seem to support those two, so there is very little we can do about this.

As for VMWare, the reason behind it not accepting compressed or packed instances created by ovfconverter seems to be related to the old vmdk version.

Problems on newest VirtualBox

In Oracle VM Virtualbox 4.0+ there seems to be a problem when importing any OVF instance created by ovfconverter. Reasons are again unknown, this will be investigated.

Disk space

The disk space requirements for both import and export are at the moment very large - we require free space up to about 3-4 times the size of disks. This will most likely be changed in future versions.