7:06 p.m.
When using oVirt >= 4.3, we can enable the NBD based backend in imageio
by specifying that we transfer raw data when creating a transfer.
With the NBD backend, we can specify qcow2 disk format.
I think we need a way to expose the capabilities of the output to the
user. For example, can we use qcow2 format.
Issues:
- I hacked qemu-img convert command line to always use -O raw instead of
"-O t.target_format" since oVirt always starts qemu-nbd with the actual
disk format. This works for this plugin, but may be wrong for other
plugins.
---
v2v/output_rhv_upload.ml | 5 ++---
v2v/rhv-upload-plugin.py | 19 +++++++++++++++++++
v2v/v2v.ml | 4 +++-
3 files changed, 24 insertions(+), 4 deletions(-)
diff --git a/v2v/output_rhv_upload.ml b/v2v/output_rhv_upload.ml
index 3514714b..481eb482 100644
--- a/v2v/output_rhv_upload.ml
+++ b/v2v/output_rhv_upload.ml
@@ -174,7 +174,7 @@ See also the virt-v2v-output-rhv(1) manual.")
error (f_"nbdkit was compiled without SELinux support. You will have to
recompile nbdkit with libselinux-devel installed, or else set SELinux to Permissive mode
while doing the conversion.")
in
- (* Output format/sparse must be raw/sparse. We may be able to
+ (* Output sparse must be sparse. We may be able to
* lift this limitation in future, but it requires changes on the
* RHV side. See TODO file for details. XXX
*)
@@ -333,8 +333,7 @@ object
let disk_format =
match target_format with
| "raw" as fmt -> fmt
- | "qcow2" ->
- error_current_limitation "-of raw"
+ | "qcow2" as fmt -> fmt
| _ ->
error (f_"rhv-upload: -of %s: Only output format ‘raw’ or ‘qcow2’ is
supported. If the input is in a different format then force one of these output formats
by adding either ‘-of raw’ or ‘-of qcow2’ on the command line.")
target_format in
diff --git a/v2v/rhv-upload-plugin.py b/v2v/rhv-upload-plugin.py
index a2d09458..4272a89f 100644
--- a/v2v/rhv-upload-plugin.py
+++ b/v2v/rhv-upload-plugin.py
@@ -17,6 +17,7 @@
# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
import builtins
+import inspect
import json
import logging
import socket
@@ -456,6 +457,8 @@ def create_disk(connection):
name = params['disk_name'],
description = "Uploaded by virt-v2v",
format = disk_format,
+ # XXX For qcow2 disk on block storage, we should use the estimated
+ # size, based on qemu-img measure of the overlay.
initial_size = params['disk_size'],
provisioned_size = params['disk_size'],
# XXX Ignores params['output_sparse'].
@@ -497,11 +500,16 @@ def create_transfer(connection, disk, host):
system_service = connection.system_service()
transfers_service = system_service.image_transfers_service()
+ extra = {}
+ if transfer_supports_format():
+ extra["format"] = types.DiskFormat.RAW
+
transfer = transfers_service.add(
types.ImageTransfer(
disk = types.Disk(id = disk.id),
host = host,
inactivity_timeout = 3600,
+ **extra,
)
)
@@ -531,6 +539,17 @@ def create_transfer(connection, disk, host):
return transfer
+def transfer_supports_format():
+ """
+ Return True if transfer supports the "format" argument, enabing the NBD
+ bakend on imageio side, which allows uploading to qcow2 images.
+
+ This feature was added in ovirt 4.3. We assume that the SDK version matches
+ engine version.
+ """
+ sig = inspect.signature(types.ImageTransfer)
+ return "format" in sig.parameters
+
# oVirt imageio operations
def parse_transfer_url(transfer):
diff --git a/v2v/v2v.ml b/v2v/v2v.ml
index 03590c9e..58bb06c3 100644
--- a/v2v/v2v.ml
+++ b/v2v/v2v.ml
@@ -739,7 +739,9 @@ and copy_targets cmdline targets input output =
| TargetURI uri -> uri in
[ "qemu-img"; "convert" ] @
(if not (quiet ()) then [ "-p" ] else []) @
- [ "-n"; "-f"; "qcow2"; "-O";
t.target_format ] @
+ (* XXX When using NBD we must use raw format, not the target_format
+ * which is the disk format. commpressed format will also not work. *)
+ [ "-n"; "-f"; "qcow2"; "-O";
"raw" ] @
(if cmdline.compressed then [ "-c" ] else []) @
[ "-S"; "64k" ] @
[ overlay_file; filename ] in
--
2.21.0