Re: [Xen-devel] [Patch[ xl problems with xendomains

[Fabio Fantoni <fabio.fantoni@xxxxxxx>]

Il 21/05/2013 23:12, Ian Murray ha scritto:
> Hi,
>
> Ever since xl become the preferred toolstack, I have had problems 
> using the xendomains startup/shutdown script.  Having retested today, 
> it seems that the issues are now reduced down to xendomains being 
> unable to restart previously saved domains.
> Here is a typical session using xl running Xen 4.2.2 on Ubuntu 64 
> 12.04 bit server, using stock Dom0 kernel (3.2.0-43-generic)
> root@xen6:/etc/init.d# service xendomains start
> root@xen6:/etc/init.d# service xendomains stop
> Shutting down Xen domains: *   [done]
> root@xen6:/etc/init.d# xl create /etc/xen/vpn2
> Parsing config from /etc/xen/vpn2
> Daemon running with PID 3969
> root@xen6:/etc/init.d# service xendomains start
> root@xen6:/etc/init.d# service xendomains stop
> Shutting down Xen domains: vpn2(save)....
>  *   [done]
> root@xen6:/etc/init.d# service xendomains start
> Restoring Xen domains:/etc/init.d/xendomains: line 258: [: too many 
> arguments
>  *   [done]
> root@xen6:/# rm /var/lib/xen/save/vpn2
>
> Line 258 reads as:-
>
> -                if [ $HEADER = "LinuxGuestRecord" ]; then
>
> There were further issues of xendomains not suspending domains 
> properly but this appear resolved now because I think the behaviour of 
> xl list -l has changed. AFAIR an extra 'domain' identifier was thrown 
> in which was causing issues with the regex parser.
> Anyway, as far as I can tell, the two issues that I see are that the 
> if statement at line 258 borks because there are no quotes around the 
> $HEADER. I'll leave it to the Bash gurus to explain that; I am not one 
> and I just hacked it to work.
> Secondly, it would appear that when using xl to save a running domain, 
> the header in the save file does not contain the text 
> "LinuxGuestRecord" but in fact contains "Xen saved domain". This 
> causes xendomains to miss the save files and will not try to restore 
> them. Placing a simple variable that contains the correct header text 
> appears to fix this.
> So applying the following patch to xendomains appears to ease these 
> issues. Please be aware that I haven't tested this on anything earlier 
> than 4.2.2 and hasn't been tested at all using xm, although the issues 
> with the regex would likely break xm rather than the change below. 
> Looking back at my original submission (2 years ago), I reported the 
> issues against 4.1.1. As previously stated this had more problems 
> because of differing output of xl list -l, which appears to be 
> employed by xendomains. I haven't thoroughly tested the patch against 
> every combination of domains sysreq'd, etc, but it appears to work for 
> auto start, save and restore.
> Thanks for reading and I hope this makes sense,
>
> Ian.
>
>
> Signed-off-by: Ian MURRAY <murrayie@xxxxxxxxxxx>
Tested-by: Fabio Fantoni <fabio.fantoni@xxxxxxx>
> --- xendomains.422.orig 2013-05-19 18:06:18.525195879 +0100
> +++ xendomains  2013-05-21 21:27:57.253429073 +0100
> @@ -28,10 +28,12 @@
>  ### END INIT INFO
>
>  CMD=xm
> ++HEADCOMP="LinuxGuestRecord"
>  $CMD list &> /dev/null
>  if test $? -ne 0
>  then
>         CMD=xl
> +       HEADCOMP="Xen saved domain"
>  fi
>
>  $CMD list &> /dev/null
> @@ -255,7 +257,7 @@
>          for dom in $XENDOMAINS_SAVE/*; do
>              if [ -f $dom ] ; then
>                  HEADER=`head -c 16 $dom | head -n 1 2> /dev/null`
> -                if [ $HEADER = "LinuxGuestRecord" ]; then
> +                if [ "$HEADER" = "$HEADCOMP" ]; then
>                      echo -n " ${dom##*/}"
>                      XMR=`$CMD restore $dom 2>&1 1>/dev/null`
>                      #$CMD restore $dom
>
>
>
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