Pkg xen devel - Nov 2014 - Bug#770456: Bug#770456: Please start a qemu process in domain 0.

Package: xen-utils-common
Version: 4.4.0-1
Severity: important
Tags: patch

Under some circumstances the xl toolstack needs to create a loopback
mount of a guest disk in dom0 (e.g. in order to run pygrub). Depending
on the nature of the guest disk (e.g. qcow2 or raw file image based)
this can require a qemu instance in dom0.

The upstream xencommons starts such a qemu on boot. The following patch
adds this to the Debian packages init script as well.

Once I have a bug number for this I will add it to debian/changelog and
push the result to feature/bugNNNN as usual.

Thanks,
Ian.

commit 26cce2a65c77f731e23a1395f1fe4a5da47287a4
Author: Ian Campbell <ijc at debian.org>
Date:   Fri Nov 21 11:27:45 2014 +0000

    Start a qemu process in dom0 to service the toolstacks loopback disk
attaches.
    
    This is used to e.g. run pygrub on a VM with a qcow2 disk image.
    
    Also, remove correct pidfile when stopping xenconsoled.

diff --git a/debian/changelog b/debian/changelog
index 484583f..ff48d6a 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -1,3 +1,12 @@
+xen (4.4.1-4) UNRELEASED; urgency=medium
+
+  [ Ian Campbell ]
+  * Start a qemu process in dom0 to service the toolstacks loopback disk
+    attaches.
+  * Remove correct pidfile when stopping xenconsoled.
+
+ -- Ian Campbell <ijc at debian.org>  Fri, 21 Nov 2014 11:26:40 +0000
+
 xen (4.4.1-3) unstable; urgency=medium
 
   [ Bastian Blank ]
diff --git a/debian/xen-utils-common.xen.init b/debian/xen-utils-common.xen.init
index b903877..e5f1702 100644
--- a/debian/xen-utils-common.xen.init
+++ b/debian/xen-utils-common.xen.init
@@ -37,6 +37,9 @@ XENCONSOLED="$ROOT"/bin/xenconsoled
 XENCONSOLED_PIDFILE="/var/run/xenconsoled.pid"
 XENSTORED="$ROOT"/bin/xenstored
 XENSTORED_PIDFILE="/var/run/xenstore.pid"
+QEMU=/usr/bin/qemu-system-i386
+QEMU_PIDFILE="/var/run/qemu-dom0.pid"
+QEMU_ARGS="-xen-domid 0 -xen-attach -name dom0 -nographic -M xenpv
-daemonize -monitor /dev/null -serial /dev/null -parallel /dev/null"
 
 modules_setup()
 {
@@ -179,10 +182,65 @@ xenconsoled_stop_real()
 	[ "$RETVAL" = 2 ] && return 2
 	start-stop-daemon --stop --quiet --oknodo --retry=0/30/KILL/5 --exec
"$XENCONSOLED"
 	[ "$?" = 2 ] && return 2
-	rm -f $PIDFILE
+	rm -f $XENCONSOLED_PIDFILE
 	return "$RETVAL"
 }
 
+qemu_start()
+{
+	[ -x $QEMU ] || return 0
+	log_progress_msg "qemu"
+	qemu_start_real
+	return $?
+}
+
+qemu_stop()
+{
+	[ -x $QEMU ] || return 0
+	log_progress_msg "qemu"
+	qemu_stop_real
+	return $?
+}
+
+qemu_restart()
+{
+	[ -x $QEMU ] || return 0
+	log_progress_msg "qemu"
+	qemu_stop_real
+	case "$?" in
+		0|1)
+		qemu_start_real
+		case "$?" in
+			0) ;;
+			*) return 2 ;;
+		esac
+		;;
+		*) return 2 ;;
+	esac
+	return 0
+}
+
+qemu_start_real()
+{
+	start-stop-daemon --start --quiet --pidfile "$QEMU_PIDFILE" --exec
"$QEMU" --test > /dev/null \
+		|| return 1
+	start-stop-daemon --start --quiet --pidfile "$QEMU_PIDFILE" --exec
"$QEMU" -- \
+		$QEMU_ARGS -pidfile "$QEMU_PIDFILE" \
+		|| return 2
+}
+
+qemu_stop_real()
+{
+	start-stop-daemon --stop --quiet --retry=TERM/30/KILL/5 --pidfile
"$QEMU_PIDFILE" --name xenconsoled
+	RETVAL="$?"
+	[ "$RETVAL" = 2 ] && return 2
+	start-stop-daemon --stop --quiet --oknodo --retry=0/30/KILL/5 --exec
"$QEMU"
+	[ "$?" = 2 ] && return 2
+	rm -f $QEMU_PIDFILE
+	return "$RETVAL"
+}
+
+
 xenstored_start()
 {
 	log_progress_msg "xenstored"
@@ -227,6 +285,11 @@ case "$1" in
 		0|1) ;;
 		*) log_end_msg 1; exit ;;
 	esac
+	qemu_start
+	case "$?" in
+		0|1) ;;
+		*) log_end_msg 1; exit ;;
+	esac
 	log_end_msg 0
 	;;
   stop)
@@ -237,6 +300,11 @@ case "$1" in
 	esac
 	log_daemon_msg "Stopping $DESC"
 	ret=0
+	qemu_stop
+	case "$?" in
+		0|1) ;;
+		*) ret=1 ;;
+	esac
 	xend_stop
 	case "$?" in
 		0|1) ;;
@@ -257,6 +325,11 @@ case "$1" in
 	esac
 	log_daemon_msg "Restarting $DESC"
 	ret=0
+	qemu_restart
+	case "$?" in
+		0|1) ;;
+		*) ret=1 ;;
+	esac
 	xend_restart
 	case "$?" in
 		0|1) ;;

On 21.11.2014 13:50, Ian Campbell wrote:
> Package: xen-utils-common
> Version: 4.4.0-1
> Severity: important
> Tags: patch
> 
> Under some circumstances the xl toolstack needs to create a loopback
> mount of a guest disk in dom0 (e.g. in order to run pygrub). Depending
> on the nature of the guest disk (e.g. qcow2 or raw file image based)
> this can require a qemu instance in dom0.
> 
> The upstream xencommons starts such a qemu on boot. The following patch
> adds this to the Debian packages init script as well.
> 
> Once I have a bug number for this I will add it to debian/changelog and
> push the result to feature/bugNNNN as usual.
> 
> Thanks,
> Ian.
> 
> commit 26cce2a65c77f731e23a1395f1fe4a5da47287a4
> Author: Ian Campbell <ijc at debian.org>
> Date:   Fri Nov 21 11:27:45 2014 +0000
> 
>     Start a qemu process in dom0 to service the toolstacks loopback disk
attaches.
>     
>     This is used to e.g. run pygrub on a VM with a qcow2 disk image.
>     
>     Also, remove correct pidfile when stopping xenconsoled.
> 
> diff --git a/debian/changelog b/debian/changelog
> index 484583f..ff48d6a 100644
> --- a/debian/changelog
> +++ b/debian/changelog
> @@ -1,3 +1,12 @@
> +xen (4.4.1-4) UNRELEASED; urgency=medium
> +
> +  [ Ian Campbell ]
> +  * Start a qemu process in dom0 to service the toolstacks loopback disk
> +    attaches.
> +  * Remove correct pidfile when stopping xenconsoled.
> +
> + -- Ian Campbell <ijc at debian.org>  Fri, 21 Nov 2014 11:26:40
+0000
> +
>  xen (4.4.1-3) unstable; urgency=medium
>  
>    [ Bastian Blank ]
> diff --git a/debian/xen-utils-common.xen.init
b/debian/xen-utils-common.xen.init
...
> +
> +qemu_start_real()
> +{
> +	start-stop-daemon --start --quiet --pidfile "$QEMU_PIDFILE"
--exec "$QEMU" --test > /dev/null \
> +		|| return 1
> +	start-stop-daemon --start --quiet --pidfile "$QEMU_PIDFILE"
--exec "$QEMU" -- \
> +		$QEMU_ARGS -pidfile "$QEMU_PIDFILE" \
> +		|| return 2
> +}
> +
> +qemu_stop_real()
> +{
> +	start-stop-daemon --stop --quiet --retry=TERM/30/KILL/5 --pidfile
"$QEMU_PIDFILE" --name xenconsoled
> +	RETVAL="$?"
> +	[ "$RETVAL" = 2 ] && return 2
> +	start-stop-daemon --stop --quiet --oknodo --retry=0/30/KILL/5 --exec
"$QEMU"
> +	[ "$?" = 2 ] && return 2
> +	rm -f $QEMU_PIDFILE
> +	return "$RETVAL"
> +}
> +
> +
Not sure this already was handled but the --name argument of qemu_stop_real
seems a copy-and-paste bug. Playing with it right now, --exec instead of --name
also works out better since qemu-system-i386 is just about too long.

-Stefan

-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 819 bytes
Desc: OpenPGP digital signature
URL:
<http://lists.alioth.debian.org/pipermail/pkg-xen-devel/attachments/20141127/d67efba9/attachment.sig>

On Thu, 2014-11-27 at 11:02 +0100, Stefan Bader wrote:
> On 21.11.2014 13:50, Ian Campbell wrote:
> > Package: xen-utils-common
> > Version: 4.4.0-1
> > Severity: important
> > Tags: patch
> > 
> > Under some circumstances the xl toolstack needs to create a loopback
> > mount of a guest disk in dom0 (e.g. in order to run pygrub). Depending
> > on the nature of the guest disk (e.g. qcow2 or raw file image based)
> > this can require a qemu instance in dom0.
> > 
> > The upstream xencommons starts such a qemu on boot. The following
patch
> > adds this to the Debian packages init script as well.
> > 
> > Once I have a bug number for this I will add it to debian/changelog
and
> > push the result to feature/bugNNNN as usual.
> > 
> > Thanks,
> > Ian.
> > 
> > commit 26cce2a65c77f731e23a1395f1fe4a5da47287a4
> > Author: Ian Campbell <ijc at debian.org>
> > Date:   Fri Nov 21 11:27:45 2014 +0000
> > 
> >     Start a qemu process in dom0 to service the toolstacks loopback
disk attaches.
> >     
> >     This is used to e.g. run pygrub on a VM with a qcow2 disk image.
> >     
> >     Also, remove correct pidfile when stopping xenconsoled.
> > 
> > diff --git a/debian/changelog b/debian/changelog
> > index 484583f..ff48d6a 100644
> > --- a/debian/changelog
> > +++ b/debian/changelog
> > @@ -1,3 +1,12 @@
> > +xen (4.4.1-4) UNRELEASED; urgency=medium
> > +
> > +  [ Ian Campbell ]
> > +  * Start a qemu process in dom0 to service the toolstacks loopback
disk
> > +    attaches.
> > +  * Remove correct pidfile when stopping xenconsoled.
> > +
> > + -- Ian Campbell <ijc at debian.org>  Fri, 21 Nov 2014 11:26:40
+0000
> > +
> >  xen (4.4.1-3) unstable; urgency=medium
> >  
> >    [ Bastian Blank ]
> > diff --git a/debian/xen-utils-common.xen.init
b/debian/xen-utils-common.xen.init
> ...
> > +
> > +qemu_start_real()
> > +{
> > +	start-stop-daemon --start --quiet --pidfile
"$QEMU_PIDFILE" --exec "$QEMU" --test > /dev/null \
> > +		|| return 1
> > +	start-stop-daemon --start --quiet --pidfile
"$QEMU_PIDFILE" --exec "$QEMU" -- \
> > +		$QEMU_ARGS -pidfile "$QEMU_PIDFILE" \
> > +		|| return 2
> > +}
> > +
> > +qemu_stop_real()
> > +{
> > +	start-stop-daemon --stop --quiet --retry=TERM/30/KILL/5 --pidfile
"$QEMU_PIDFILE" --name xenconsoled
> > +	RETVAL="$?"
> > +	[ "$RETVAL" = 2 ] && return 2
> > +	start-stop-daemon --stop --quiet --oknodo --retry=0/30/KILL/5 --exec
"$QEMU"
> > +	[ "$?" = 2 ] && return 2
> > +	rm -f $QEMU_PIDFILE
> > +	return "$RETVAL"
> > +}
> > +
> > +
> 
> Not sure this already was handled but the --name argument of qemu_stop_real
> seems a copy-and-paste bug.
Yes it is, whoops!
>  Playing with it right now, --exec instead of --name
> also works out better since qemu-system-i386 is just about too long.
So it is, so this is probably a good idea.

Will you send an updated patch once you've finished testing?

Ian.

Your message dated Thu, 22 Dec 2016 18:49:44 +0000
with message-id <E1cK8Qy-0003n4-E2 at fasolo.debian.org>
and subject line Bug#770456: fixed in xen 4.8.0-1
has caused the Debian Bug report #770456,
regarding Please start a qemu process in domain 0.
to be marked as done.

This means that you claim that the problem has been dealt with.
If this is not the case it is now your responsibility to reopen the
Bug report if necessary, and/or fix the problem forthwith.

(NB: If you are a system administrator and have no idea what this
message is talking about, this may indicate a serious mail system
misconfiguration somewhere. Please contact owner at bugs.debian.org
immediately.)


-- 
770456: http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=770456
Debian Bug Tracking System
Contact owner at bugs.debian.org with problems
-------------- next part --------------
An embedded message was scrubbed...
From: Ian Campbell <ijc at debian.org>
Subject: Please start a qemu process in domain 0.
Date: Fri, 21 Nov 2014 12:50:44 +0000
Size: 5465
URL:
<http://lists.alioth.debian.org/pipermail/pkg-xen-devel/attachments/20161222/73b9dc50/attachment.mht>
-------------- next part --------------
An embedded message was scrubbed...
From: Ian Jackson <ian.jackson at eu.citrix.com>
Subject: Bug#770456: fixed in xen 4.8.0-1
Date: Thu, 22 Dec 2016 18:49:44 +0000
Size: 11332
URL:
<http://lists.alioth.debian.org/pipermail/pkg-xen-devel/attachments/20161222/73b9dc50/attachment-0001.mht>