1:12 a.m.
For traversing a backing chain of VMDK descriptor files over ssh, two
things are necessary:
- qemu-nbd with the ssh block driver, rather than nbdkit-ssh-plugin,
- a remote SSH URL (for qemu-nbd) without a query string appended, as
qemu-nbd cannot update the last pathname component (for tracking the
relative pathnames of VMDK descriptor files) if a query string is
appended.
Before commit 7a6f6113a25f ("v2v: -i vmx -it ssh: Replace qemu block ssh
driver with nbdkit-ssh-plugin.", 2019-10-08), we passed the
"?host_key_check=no" query string in the URL to qemu-nbd, so we can't just
return to that, for accessing snapshotted guests with vmx+ssh.
But, we shouldn't return to qemu-nbd for vmx+ssh even without a query
string, as that would undo the other benefit(s) of commit 7a6f6113a25f.
Instead, clearly document that snapshotted guests are not supported over
vmx+ssh, and cleanly reject this situation in the code as well. Recommend
the two alternative transports that allow the user to convert such guests.
Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1774386
Signed-off-by: Laszlo Ersek <lersek(a)redhat.com>
---
Notes:
v2:
- in the manual, centralize the description in a new NOTES section, and
reference that section from "-i vmx -it ssh" and "INPUT FROM VMWARE
VMX" [Rich]
- in the code, bail out with error (f_"...") rather than failwith, for
enabling translations [Rich]
- in the error message printed from the code, recommend actions to the
user (reference the new NOTES section of the manual) [Rich]
input/input_vmx.ml | 27 ++++++++------------
docs/virt-v2v-input-vmware.pod | 18 ++++++++++++-
2 files changed, 27 insertions(+), 18 deletions(-)
diff --git a/input/input_vmx.ml b/input/input_vmx.ml
index 9921419b5a85..eed8a4335622 100644
--- a/input/input_vmx.ml
+++ b/input/input_vmx.ml
@@ -81,23 +81,16 @@ module VMX = struct
let vmx_path = path_of_uri uri in
let abs_path = absolute_path_from_other_file vmx_path filename in
- let format = "vmdk" in
+ let flat_vmdk = PCRE.replace (PCRE.compile "\\.vmdk$")
+ "-flat.vmdk" abs_path in
- (* XXX This is a hack to work around qemu / VMDK limitation
- * "Cannot use relative extent paths with VMDK descriptor file"
- * We can remove this if the above is fixed.
- *)
- let abs_path, format =
- let flat_vmdk =
- PCRE.replace (PCRE.compile "\\.vmdk$") "-flat.vmdk"
abs_path in
- if remote_file_exists uri flat_vmdk then (flat_vmdk, "raw")
- else (abs_path, format) in
-
- (* XXX In virt-v2v 1.42+ importing from VMX over SSH
- * was broken if the -flat.vmdk file did not exist.
- * It is still broken here.
- *)
- ignore format;
+ (* RHBZ#1774386 *)
+ if not (remote_file_exists uri flat_vmdk) then
+ error (f_"This transport does not support guests with snapshots. \
+ Either collapse the snapshots for this guest and try \
+ the conversion again, or use one of the alternate \
+ conversion methods described in \
+ virt-v2v-input-vmware(1) section \"NOTES\".");
let server = server_of_uri uri in
let port = Option.map string_of_int (port_of_uri uri) in
@@ -110,7 +103,7 @@ module VMX = struct
let cor = dir // "convert" in
let bandwidth = options.bandwidth in
let nbdkit = Nbdkit_ssh.create_ssh ?bandwidth ~cor ~password
- ~server ?port ?user abs_path in
+ ~server ?port ?user flat_vmdk in
let _, pid = Nbdkit.run_unix socket nbdkit in
On_exit.kill pid
) filenames
diff --git a/docs/virt-v2v-input-vmware.pod b/docs/virt-v2v-input-vmware.pod
index 2c90e0afc7cd..66ca5f00d28a 100644
--- a/docs/virt-v2v-input-vmware.pod
+++ b/docs/virt-v2v-input-vmware.pod
@@ -51,6 +51,9 @@ to ESXi to read the F<GUEST.vmx> file and associated disks. This
requires that you have enabled SSH access to the VMware ESXi
hypervisor - in the default ESXi configuration this is turned off.
+This transport is incompatible with guests that have snapshots; refer
+to L</NOTES>.
+
=item B<-ic vpx://...> B<-it vddk>
=item B<-ic esx://...> B<-it vddk>
@@ -84,6 +87,18 @@ import a guest from VMware vCenter. This is the slowest method.
=back
+=head1 NOTES
+
+When accessing the F<I<guest>.vmx> file on ESXi over an SSH connection
+(that is, when using the B<-i vmx> B<-it ssh> options), the conversion
+will not work if the guest has snapshots (files called
+F<I<guest>-000001.vmdk> and similar). Either collapse the snapshots
+for the guest and retry the conversion with the same
+B<-i vmx> B<-it ssh> options, or leave the snapshots intact and use a
+transport different from SSH: just B<-i vmx>, or
+B<-ic vpx://...> B<-it vddk> or B<-ic esx://...> B<-it vddk>.
Refer
+to L<https://bugzilla.redhat.com/1774386>;.
+
=head1 INPUT FROM VMWARE VMX
Virt-v2v is able to import guests from VMware’s vmx files.
@@ -106,7 +121,8 @@ a C</vmfs/volumes> folder containing the virtual machines.
If you find a folder of files called F<I<guest>.vmx>,
F<I<guest>.vmxf>, F<I<guest>.nvram> and one or more
F<.vmdk> disk
-images, then you can use this method.
+images, then you can use this method. The SSH transport is not usable
+if the guest has snapshots; refer to L</NOTES>.
=head2 VMX: Guest must be shut down
--
2.19.1.3.g30247aa5d201