[Libguestfs] [PATCH v3] windows: delay installation of qemu-ga MSI

[Richard W.M. Jones]

On Tue, Mar 03, 2020 at 03:45:49PM +0100, Tomáš Golembiovský wrote:
> Instead of running firstboot script during early boot schedule a task
> delayed for 2 minutes.
> 
> During the first boot, after virt-v2v conversion, Windows installs the
> drivers injected by virt-v2v. When this installation is finished
> Windows enforces some kind of internal reboot. This unfortunately
> terminates any running firstboot scripts thus killing the installation
> of qemu-ga MSI.
> 
> This is just a best-effort mitigation. It can still happen (e.g. with
> slow disk drives) that the drivers are not yet installed when the
> delayed installation starts. On the other hand we cannot delay it too
> much otherwise we risk that the users logs in and will be doing some
> work when the MSI installation starts. After MSI installation finishes
> the VM needs to be rebooted which would be annoying if that would happen
> under users hands. Although this is not a best fix (that may come later
> as it is more complex, e.g. introducing waiting mechanism), the delay as
> it is defined works in most cases. And it dramaticaly improves the
> situations -- originaly I experienced more than 90% failure rate.
> 
> Signed-off-by: Tomáš Golembiovský <tgolembi at redhat.com>
> ---
>  common                 |  2 +-
>  v2v/convert_windows.ml | 12 ++++--------
>  2 files changed, 5 insertions(+), 9 deletions(-)
> 
> diff --git a/common b/common
> index ea10827b..5371257c 160000
> --- a/common
> +++ b/common
> @@ -1 +1 @@
> -Subproject commit ea10827b4cfb3cfe5f782421c01d2902e5f73f90
> +Subproject commit 5371257c3cf27fb09d5f2e31ba378b0e6ccf5df6
> diff --git a/v2v/convert_windows.ml b/v2v/convert_windows.ml
> index 0fda1d4e..bed5989a 100644
> --- a/v2v/convert_windows.ml
> +++ b/v2v/convert_windows.ml
> @@ -429,14 +429,10 @@ popd
>     List.iter (
>       fun msi_path ->
>         let fb_script = "\
> -echo Installing qemu-ga from " ^ msi_path ^ "
> -\"\\" ^ msi_path ^ "\" /norestart /qn /l+*vx \"%~dpn0.log\"
> -set elvl=!errorlevel!
> -echo Done installing qemu-ga error_level=!elvl!
> -if !elvl! == 0 (
> -  echo Restarting Windows...
> -  shutdown /r /f /c \"rebooted by firstboot script\"
> -)
> +echo Removing any previously scheduled qemu-ga installation
> +schtasks.exe /Delete /TN Firstboot-qemu-ga /F
> +echo Scheduling delayed installation of qemu-ga from " ^ msi_path ^ "
> +powershell.exe -command \"$d = (get-date).AddSeconds(120); schtasks.exe /Create /SC ONCE /ST $d.ToString('HH:mm') /SD $d.ToString('MM/dd/yyyy') /RU SYSTEM /TN Firstboot-qemu-ga /TR \\\"C:\\" ^ msi_path ^ " /forcerestart /qn /l+*vx C:\\" ^ msi_path ^ ".log\\\"\"
>  " in
>        Firstboot.add_firstboot_script g inspect.i_root
>          ("install " ^ msi_path) fb_script;

It could be easier to follow if you use sprintf here, something like:

let fb_script = sprintf "\
echo Removing any previously scheduled qemu-ga installation
schtasks.exe /Delete /TN Firstboot-qemu-ga /F
echo Scheduling delayed installation of qemu-ga from %s
powershell.exe -command \"$d = (get-date).AddSeconds(120); schtasks.exe /Create /SC ONCE /ST $d.ToString('HH:mm') /SD $d.ToString('MM/dd/yyyy') /RU SYSTEM /TN Firstboot-qemu-ga /TR \\\"C:\\%s /forcerestart /qn /l+*vx C:\\%s.log\\\"\"
  msi_path msi_path msi_path in

The other possible problem is this seems to install a firstboot script
for every element of the list qemu_ga_files.  How long is this list?

Do filenames on this list need some kind of quoting?  The filenames
don't, but they seem to contain a path that comes from the virtio-win
ISO.

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
Read my programming and virtualization blog: http://rwmj.wordpress.com
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