[PATCH 0 of 2] xencommons init script improvements

[PATCH 0 of 2] xencommons init script improvements

[George Dunlap]

Rework of patches from yesterday, without the first one:
* Make xencommons more verbose, as normal init scripts are
* Wait for xenstored to start before attempting to set the domain name.
 - Time out after 30 seconds
 - Exit the script if the timeout fails.

If exiting is not the preferred behavior, feel free to elide the error
check. :-)

[PATCH 1 of 2] xencommons: Make init script more verbose

[George Dunlap]

Signed-off-by: George Dunlap <george.dunlap@eu.citrix.com>

diff -r 3ea84fd20b26 -r ad0f9cc72415 tools/hotplug/Linux/init.d/xencommons
--- a/tools/hotplug/Linux/init.d/xencommons	Tue Jun 29 13:43:18 2010 +0100
+++ b/tools/hotplug/Linux/init.d/xencommons	Tue Jun 29 14:56:28 2010 +0100
@@ -42,21 +42,28 @@
 		test -z "$XENSTORED_ROOTDIR" || XENSTORED_ROOTDIR="/var/lib/xenstored"
 		rm -f "$XENSTORED_ROOTDIR"/tdb* &>/dev/null
 		test -z "$XENSTORED_TRACE" || XENSTORED_ARGS=" -T /var/log/xen/xenstored-trace.log"
+
+		echo Starting xenstored...
 		xenstored --pid-file=/var/run/xenstore.pid $XENSTORED_ARGS
+		echo Setting domain 0 name...
 		xenstore-write "/local/domain/0/name" "Domain-0"
 	fi
 
+	echo Starting xenconsoled...
 	test -z "$XENCONSOLED_TRACE" || XENCONSOLED_ARGS=" -T /var/log/xen/xenstored-trace.log"
 	xenconsoled --pid-file=$XENCONSOLED_PIDFILE $XENCONSOLED_ARGS
 	test -z "$XENBACKENDD_DEBUG" || XENBACKENDD_ARGS="-d"
 	test "`uname`" != "NetBSD" || xenbackendd $XENBACKENDD_ARGS
 }
 do_stop () {
+        echo Stopping xenconsoled
 	if read 2>/dev/null <$XENCONSOLED_PIDFILE pid; then
 		kill $pid
 		while kill -9 $pid >/dev/null 2>&1; do sleep 0.1; done
 		rm -f $XENCONSOLED_PIDFILE
 	fi
+
+	echo WARNING: Not stopping xenstored, as it cannot be restarted.
 }
 
 case "$1" in

[PATCH 2 of 2] xencommons: Wait for xenstored to start before setting dom0 name

[George Dunlap]

On one of my boxes, the xenstore-write setting dom0's name starts
before xenstored is actually ready to handle the connection properly,
resulting in the name set failing.  Wait for xenstored to be up and
responding to reads before continuing, timing out after 30 seconds.

Signed-off-by: George Dunlap <george.dunlap@eu.citrix.com>

diff -r ad0f9cc72415 -r dc49f02fc463 tools/hotplug/Linux/init.d/xencommons
--- a/tools/hotplug/Linux/init.d/xencommons	Tue Jun 29 14:56:28 2010 +0100
+++ b/tools/hotplug/Linux/init.d/xencommons	Tue Jun 29 14:56:28 2010 +0100
@@ -37,14 +37,32 @@
 fi
 
 do_start () {
+        local time=0
+	local timeout=30
+
 	if ! `xenstore-read -s / >/dev/null 2>&1`
 	then
 		test -z "$XENSTORED_ROOTDIR" || XENSTORED_ROOTDIR="/var/lib/xenstored"
 		rm -f "$XENSTORED_ROOTDIR"/tdb* &>/dev/null
 		test -z "$XENSTORED_TRACE" || XENSTORED_ARGS=" -T /var/log/xen/xenstored-trace.log"
 
-		echo Starting xenstored...
+		echo -n Starting xenstored...
 		xenstored --pid-file=/var/run/xenstore.pid $XENSTORED_ARGS
+
+		# Wait for xenstored to actually come up, timing out after 30 seconds
+                while [ $time -lt $timeout ] && ! `xenstore-read -s / >/dev/null 2>&1` ; do
+                    echo -n .
+		    time=$(($time+1))
+                    sleep 1
+                done
+		echo
+
+		# Exit if we timed out
+		if ! [ $time -lt $timeout ] ; then
+		    echo Could not start xenstored
+		    exit 1
+		fi
+
 		echo Setting domain 0 name...
 		xenstore-write "/local/domain/0/name" "Domain-0"
 	fi

Re: [PATCH 2 of 2] xencommons: Wait for xenstored to start before setting dom0 name

[Ian Campbell]

On Tue, 2010-06-29 at 14:56 +0100, George Dunlap wrote:
> On one of my boxes, the xenstore-write setting dom0's name starts
> before xenstored is actually ready to handle the connection properly,
> resulting in the name set failing.  Wait for xenstored to be up and
> responding to reads before continuing, timing out after 30 seconds.

Does this make the xenstored in a stub-dom case more complicated? (due
to use of "-s")

Is the domain 0 name node special enough that we could just make
xenstored set it itself at start of day? 

Ian.

Re: [PATCH 2 of 2] xencommons: Wait for xenstored to start before setting dom0 name

[Jeremy Fitzhardinge]

On 06/29/2010 03:56 PM, George Dunlap wrote:
> On one of my boxes, the xenstore-write setting dom0's name starts
> before xenstored is actually ready to handle the connection properly,
> resulting in the name set failing.  Wait for xenstored to be up and
> responding to reads before continuing, timing out after 30 seconds.
>
> Signed-off-by: George Dunlap <george.dunlap@eu.citrix.com>
>
> diff -r ad0f9cc72415 -r dc49f02fc463 tools/hotplug/Linux/init.d/xencommons
> --- a/tools/hotplug/Linux/init.d/xencommons	Tue Jun 29 14:56:28 2010 +0100
> +++ b/tools/hotplug/Linux/init.d/xencommons	Tue Jun 29 14:56:28 2010 +0100
> @@ -37,14 +37,32 @@
>  fi
>  
>  do_start () {
> +        local time=0
> +	local timeout=30
> +
>  	if ! `xenstore-read -s / >/dev/null 2>&1`
>  	then
>  		test -z "$XENSTORED_ROOTDIR" || XENSTORED_ROOTDIR="/var/lib/xenstored"
>  		rm -f "$XENSTORED_ROOTDIR"/tdb* &>/dev/null
>  		test -z "$XENSTORED_TRACE" || XENSTORED_ARGS=" -T /var/log/xen/xenstored-trace.log"
>  
> -		echo Starting xenstored...
> +		echo -n Starting xenstored...
>  		xenstored --pid-file=/var/run/xenstore.pid $XENSTORED_ARGS
>   

Why isn't xenstored ready by the time the main process exits?  Seems
like a bug in xenstored. Does oxenstored get this right?

    J


> +
> +		# Wait for xenstored to actually come up, timing out after 30 seconds
> +                while [ $time -lt $timeout ] && ! `xenstore-read -s / >/dev/null 2>&1` ; do
> +                    echo -n .
> +		    time=$(($time+1))
> +                    sleep 1
> +                done
> +		echo
> +
> +		# Exit if we timed out
> +		if ! [ $time -lt $timeout ] ; then
> +		    echo Could not start xenstored
> +		    exit 1
> +		fi
> +
>  		echo Setting domain 0 name...
>  		xenstore-write "/local/domain/0/name" "Domain-0"
>  	fi
>
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xensource.com
> http://lists.xensource.com/xen-devel
>
>   

Re: [PATCH 2 of 2] xencommons: Wait for xenstored to start before setting dom0 name

[Ian Campbell]

On Tue, 2010-06-29 at 15:37 +0100, Jeremy Fitzhardinge wrote:
> 
> 
> Why isn't xenstored ready by the time the main process exits?  Seems
> like a bug in xenstored. Does oxenstored get this right? 

Looks like Bastian tried to fix this in C xenstored years ago with:
        changeset:   17296:21d9575c669e
        user:        Keir Fraser <keir.fraser@citrix.com>
        date:        Wed Mar 26 13:21:42 2008 +0000
        files:       tools/misc/xend tools/xenstore/xenstored_core.c
        description:
        xenstored: Delay forking until after listening sockets are
        opened. Also, in startup xend script, delay further startup until
        xenstored initial child process has exited. This serialises xenstored
        startup with that of other daemons (e.g., xenconsoled).
        
        Signed-off-by: Bastian Blank <waldi@debian.org>
But it was reverted shortly after:
        changeset:   17304:ed67f68ae2a7
        user:        Keir Fraser <keir.fraser@citrix.com>
        date:        Thu Mar 27 09:12:09 2008 +0000
        files:       tools/misc/xend tools/xenstore/xenstored_core.c
        description:
        Revert 17296:21d9575c669e.
        Signed-off-by: Keir Fraser <keir.fraser@citrix.com>
because it broke something. The thread at
http://lists.xensource.com/archives/html/xen-devel/2008-03/msg00758.html
has more details.

I'm not especially inclined to fix the C xenstored, lets hasten the
switch to oxenstored instead.

Ian.

Re: [PATCH 2 of 2] xencommons: Wait for xenstored to start before setting dom0 name

[Keir Fraser]

On 29/06/2010 16:02, "Ian Campbell" <Ian.Campbell@citrix.com> wrote:

> because it broke something. The thread at
> http://lists.xensource.com/archives/html/xen-devel/2008-03/msg00758.html
> has more details.
> 
> I'm not especially inclined to fix the C xenstored, lets hasten the
> switch to oxenstored instead.

I'd suggest disabling C xenstored build by default and install xenstored as
a symlink to oxenstored.

 -- Keir