=head1 NAME

virt-v2v-output-openstack - Using virt-v2v to convert guests to OpenStack

=head1 SYNOPSIS

 virt-v2v [-i* options] -o openstack
                        -oo server-id=SERVER
                        [-oo guest-id=GUEST]
                        [-oo verify-server-certificate=false]
                        [-oo os-username=admin] [-oo os-*=*]

 virt-v2v [-i* options] -o glance

=head1 DESCRIPTION

This page documents how to use L<virt-v2v(1)> to convert guests to run
on OpenStack.  There are two output modes you can select, but only
I<-o openstack> should be used normally.

=over 4

=item B<-o openstack> B<-oo server-id=>SERVER [...]

Full description: L</OUTPUT TO OPENSTACK>

This is the modern method for uploading to OpenStack via the REST API.
Guests can be directly converted into Cinder volumes.

=item B<-o glance>

Full description: L</OUTPUT TO GLANCE>

This is the old method for uploading to Glance.  Unfortunately Glance
is not well suited to storing converted guests (since virt-v2v deals
with "pets" not templated "cattle"), so this method is not recommended
unless you really know what you are doing.

=back

=head1 OUTPUT TO OPENSTACK

To output to OpenStack, use the I<-o openstack> option.

=head2 OpenStack: Setting up a conversion appliance

When virt-v2v is converting to OpenStack, it is unusual in that
virt-v2v B<must> be running inside a virtual machine running on top of
the OpenStack overcloud.  This virtual machine is called the
"conversion appliance".  Note this virtual machine is unrelated to the
guest which is being converted.

The reason for this is because to create Cinder volumes that will
contain the guest data (for the converted guest) we must attach those
Cinder volumes to an OpenStack virtual machine.

The C<openstack> command must be installed in the appliance.  We use
it for communicating with OpenStack.

When virt-v2v is running in the conversion appliance, you must supply
the name or UUID of the conversion appliance to virt-v2v, eg:

 $ openstack server list
 +--------------------------------------+-----------+--------+
 | ID                                   | Name      | Status |
 +--------------------------------------+-----------+--------+
 | bbb0147a-44b9-4d19-9a9d-10ca9a984744 | test1     | ACTIVE |
 +--------------------------------------+-----------+--------+

 # virt-v2v [...] \
       -o openstack -oo server-id=bbb0147a-44b9-4d19-9a9d-10ca9a984744

or:

 # virt-v2v [...] -o openstack -oo server-id=test1

You can run many parallel conversions inside a single conversion
appliance if you want, subject to having enough resources available.
However OpenStack itself imposes a limit that you should be aware of:
OpenStack cannot attach more than around 25 disks [the exact number
varies with configuration] to a single appliance, and that limits the
number of guests which can be converted in parallel, because each
guest's disk must be attached to the appliance while being copied.

=head2 OpenStack: Authentication

Converting to OpenStack requires access to the tenant (non-admin) API
endpoints.  You will need to either set up your C<$OS_*> environment
variables or use output options on the virt-v2v command line to
authenticate with OpenStack.

For example:

 export OS_USERNAME=admin

or:

 virt-v2v [...] -o openstack -oo os-username=admin

are equivalent, and have the same effect as using I<--os-username> on
the command line of OpenStack tools.

Normally there is a file called F<overcloudrc> or F<keystonerc_admin>
which you can simply C<source> to set everything up.

If you need to copy F<overcloudrc> to another machine, check if it
references the C<OS_CLOUD> environment variable.  If so, you may have
to copy the F<clouds.yaml> file from F</etc/openstack/> or
F<$HOME/.config/openstack/> to the other machine as well.  See the
section "CLOUD CONFIGURATION" in the openstack CLI manual.

=head2 OpenStack: Running as root

Because virt-v2v must access Cinder volumes which are presented as
F</dev> devices to the conversion appliance, virt-v2v must usually run
as root in I<-o openstack> mode.

If you use C<sudo> to start virt-v2v and you are using environment
variables for authentication, remember to use the C<sudo -E> option to
preserve the environment.

=head2 OpenStack: Guest ID

 virt-v2v [...] -o openstack -oo guest-id=123-456-7890

You may optionally specify I<-oo guest-id=...> on the command line.
The ID (which can be any string) is saved on each Cinder volume in the
C<virt_v2v_guest_id> volume property.

This can be used to find disks associated with a guest, or to
associate which disks are related to which guests when converting many
guests.

=head2 OpenStack: Ignore server certificate

Using I<-oo verify-server-certificate=false> you can tell the
openstack client to ignore the server certificate when connecting to
the OpenStack API endpoints.  This has the same effect as passing the
I<--insecure> option to the C<openstack> command.

=head2 OpenStack: Converting a guest

The final command to convert the guest, running as root, will be:

 # virt-v2v [-i options ...] \
       -o openstack -oo server-id=NAME|UUID [-oo guest-id=ID]

If you include authentication options on the command line then:

 # virt-v2v [-i options ...] \
       -o openstack -oo server-id=NAME|UUID -oo os-username=admin [etc]

=head2 OpenStack: Booting the guest

Guests are converted as Cinder volume(s) (one volume per disk in the
original guest).  To boot them use the
C<openstack server create --volume> option:

 $ openstack volume list
 +--------------------------------------+---------------+-----------+
 | ID                                   | Name          | Status    |
 +--------------------------------------+---------------+-----------+
 | c4d06d15-22ef-462e-9eff-ab54ab285a1f | fedora-27-sda | available |
 +--------------------------------------+---------------+-----------+
 $ openstack server create \
       --flavor x1.small \
       --volume c4d06d15-22ef-462e-9eff-ab54ab285a1f \
       myguest
 $ openstack console url show myguest

=head2 OpenStack: Other conversion options

To specify the Cinder volume type, use I<-os>.  If not specified then
no Cinder volume type is used.

The following options are B<not> supported with OpenStack: I<-oa>,
I<-of>.

=head1 OUTPUT TO GLANCE

Note this is a legacy option.  In most cases you should use
L</OUTPUT TO OPENSTACK> instead.

To output to OpenStack Glance, use the I<-o glance> option.

This runs the L<glance(1)> CLI program which must be installed on the
virt-v2v conversion host.  For authentication to work, you will need
to set C<OS_*> environment variables.  See
L</OpenStack: Authentication> above.

Virt-v2v adds metadata for the guest to Glance, describing such things
as the guest operating system and what drivers it requires.  The
command C<glance image-show> will display the metadata as "Property"
fields such as C<os_type> and C<hw_disk_bus>.

=head2 Glance and sparseness

Glance image upload doesn't appear to correctly handle sparseness.
For this reason, using qcow2 will be faster and use less space on the
Glance server.  Use the virt-v2v S<I<-of qcow2>> option.

=head2 Glance and multiple disks

If the guest has a single disk, then the name of the disk in Glance
will be the name of the guest.  You can control this using the I<-on>
option.

Glance doesn't have a concept of associating multiple disks with a
single guest, and Nova doesn't allow you to boot a guest from multiple
Glance disks either.  If the guest has multiple disks, then the first
(assumed to be the system disk) will have the name of the guest, and
the second and subsequent data disks will be called
C<I<guestname>-disk2>, C<I<guestname>-disk3> etc.  It may be best to
leave the system disk in Glance, and import the data disks to Cinder.

=head1 SEE ALSO

L<virt-v2v(1)>,
L<https://docs.openstack.org/python-openstackclient/latest/cli/man/openstack.html>,
L<glance(1)>.

=head1 AUTHOR

Richard W.M. Jones

=head1 COPYRIGHT

Copyright (C) 2009-2025 Red Hat Inc.
