EL6 initscript feedback.

* EL6 initscript feedback.
@ 2013-05-21  3:01 Steven Haigh
  2013-05-21 11:20 ` Stefano Stabellini
  0 siblings, 1 reply; 8+ messages in thread
From: Steven Haigh @ 2013-05-21  3:01 UTC (permalink / raw)
  To: xen-devel

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Hi all,

I'm throwing in my initscript here that I've been pushing to autostart 
xen domains on system boot.

There are at least one issue right now that I'm not 100% sure how to 
handle - and that is domains created by libvirt. These continue to show 
in an xm/xl list output even when they are not paused / running / 
blocked - causing my initscript to think they are still running.

The ways I can think of detecting this are *very* hacky and I wouldn't 
feel comfortable to including them in widely used packages.

I'm wondering if people have some spare time that they review the logic 
in this initscript and provide feedback / suggestions / fixes / 
improvements that I can roll into the scripts to enhance them for all.

Thanks.

-- 
Steven Haigh

Email: netwiz@crc.id.au
Web: https://www.crc.id.au
Phone: (03) 9001 6090 - 0412 935 897
Fax: (03) 8338 0299

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#!/bin/bash
#
# /etc/init.d/xendomains
# Start / stop domains automatically when domain 0 boots / shuts down.
#
# chkconfig: 345 99 00
# description: Start / stop Xen domains.
#
# Re-written from scratch by Steven Haigh <netwiz@crc.id.au> for EL6 as stock
# script has a lot of problems. May work on other distros, YMMV.
#
### BEGIN INIT INFO
# Provides:          xendomains
# Required-Start:    $syslog $remote_fs xenstored xenconsoled
# Should-Start:      xend
# Required-Stop:     $syslog $remote_fs xenstored xenconsoled
# Should-Stop:       xend
# Default-Start:     2 3 4 5
# Default-Stop:      0 1 6
# Short-Description: Start/stop secondary xen domains
# Description:       Start / stop domains automatically when domain 0 
#                    boots / shuts down.
### END INIT INFO

## Check if Xend is running, if so, use xm, else xl.
XEND=`pidof -x xend`
if [ $? -eq 0 ]; then
	CMD=`which xm`
else
	CMD=`which xl`
fi

## Check to see if we're running as Dom0. If so, the following file should
## exist.
if ! [ -e /proc/xen/privcmd ]; then
	echo "Not running as Domain0. Exiting..."
	exit 0
fi

## Load the xendomains options, bailing if we can't.
if [ -r /etc/sysconfig/xendomains ]; then
	. /etc/sysconfig/xendomains
else
	echo "/etc/sysconfig/xendomains not found or unreadable. This is an issue. Exiting..."
	exit 0
fi

if [ -d /var/lock/subsys ]; then
	LOCKFILE=/var/lock/subsys/xendomains
else
	LOCKFILE=/var/lock/xendomains
fi

## Source function library.
. /etc/init.d/functions

get_domu_name() {
    DOMU_NAME=$(awk '/^name/ {print $3}' $1)
}

watchdog() {
	## Launch a command and wait until the timeout before killing forcefully.
	for WAIT in `seq 0 $XENDOMAINS_STOP_MAXWAIT`; do
		RESULT=`ps -p $PID`
		if [ $? -eq 1 ]; then
			success; echo
			break
		fi
		echo -n "."
		sleep 1
	done
	RESULT=`ps -p $PID`
	if [ $? -eq 0 ]; then
		warning; echo
		kill $PID
	fi
	echo
}

start() {
	touch $LOCKFILE

	## Check to see if we should restore saved DomUs on start
	## Also check if the restore directory actually exists.
	if [ "$XENDOMAINS_RESTORE" = "true" ] && [ -d $XENDOMAINS_SAVE ] && [ -n "$XENDOMAINS_SAVE" ]; then
		for DOMU in $XENDOMAINS_SAVE/*; do
			if [ -r $DOMU ]; then
				HEADER=`head -c 16 $DOMU | head -n 1 2> /dev/null`
				if [ "$HEADER" = "LinuxGuestRecord" ] || [ "$HEADER" = "Xen saved domain" ]; then
					echo -n "Restoring Xen Domain ${DOMU##*/}"
					RESULT=`$CMD restore $DOMU 2>&1 1>/dev/null`
					if [ $? -ne 0 ]; then
						failure; echo
					else
						success; echo
					fi
					rm -f "$DOMU"
				fi
			fi
		done
	fi

	## Check to see if our autostart directory exists and is actually set.
	if [ -d $XENDOMAINS_AUTO ] && [ -n $XENDOMAINS_AUTO ]; then
		## Start each domain in our autostart directory.
		for DOMU in $XENDOMAINS_AUTO/*; do
			get_domu_name $DOMU
			echo -n $"Starting Xen auto domain $DOMU_NAME: "

			## Check if domain is already running.
			RESULT=`$CMD list $DOMU_NAME >& /dev/null`
			if [ $? -eq 0 ] && [ $? -ne 2 ]; then
				## DomU is already running.
				echo -n " (Skipped - Already running)"
			else
				## Start the DomU...
				RESULT=`$CMD create $DOMU >& /dev/null`
				if [ $? -eq 0 ]; then
					usleep $XENDOMAINS_CREATE_USLEEP
					success; echo
				else
					failure; echo
				fi
			fi
		done
	fi

	return 0
}

stop() {
	## Check to see if we should send a SysRq to the DomUs
	if [ -n "$XENDOMAINS_SYSRQ" ]; then
		IFS=$'\n'
		echo -n "Sending SYSRQs to Xen Domains:"
		for DOMU in `$CMD list | tail -n +3 | sort`; do
			unset IFS
			DOMU_NAME=`echo "$DOMU" | awk '{ print $1 }'`
			for sysrq in $XENDOMAINS_SYSRQ; do
				$CMD sysrq $DOMU_NAME $sysrq
				echo -n "."
			done
		done
		success; echo
	fi

	## Check to see if we should migrate running domains...
	if [ -n "$XENDOMAINS_MIGRATE" ]; then
		## We should be doing a migrate. We don't really do much, just pass the
		## values to XM/XL - if it fails, save or shutdown can have a go.
		IFS=$'\n'
		for DOMU in `$CMD list | tail -n +3 | sort`; do
			unset IFS
			DOMU_NAME=`echo "$DOMU" | awk '{ print $1 }'`
			echo -n "Migrating Xen domain $DOMU_NAME: "
			$CMD migrate $DOMU_NAME $XENDOMAINS_MIGRATE 2>&1 1>/dev/null &
			PID=$!
			watchdog
		done
	fi

	## Check to see if we are to save domains...
	if [ -d $XENDOMAINS_SAVE ] && [ -n "$XENDOMAINS_SAVE" ]; then
		## Cycle through the domains running and do what we need to do.
		IFS=$'\n'
		for DOMU in `$CMD list | tail -n +3 | sort`; do
			unset IFS
			DOMU_NAME=`echo "$DOMU" | awk '{ print $1 }'`

			## Now we set our ionice to lower than realtime as we don't want the
			## system to become unresponsive while saving a DomU. It still may
			## need to fulfil requests from other DomUs etc.
			ionice -c 2 -n 7 -p $$

			echo -n "Saving Xen Domain $DOMU_NAME: "
			$CMD save $DOMU_NAME $XENDOMAINS_SAVE/$DOMU_NAME > /dev/null 2>&1 &
			PID=$!
			watchdog
		done
	fi

	## Shut down the remaining domains...
	if [ -n "$XENDOMAINS_SHUTDOWN" ]; then
		if [ "$CMD" = `which xm` ]; then
			echo -n "Sending shutdown to all DomUs: "
			$CMD shutdown --all
			success; echo
		else
			IFS=$'\n'
			for DOMU in `$CMD list | tail -n +3 | sort`; do
				unset IFS
				DOMU_NAME=`echo "$DOMU" | awk '{ print $1 }'`
				echo -n "Sending shutdown to DomU $DOMU_NAME:"
				$CMD shutdown -F "$DOMU_NAME"
				success; echo
			done
		fi

		echo "Waiting for all DomUs to complete shutdown"
		for WAIT in `seq 0 $XENDOMAINS_STOP_MAXWAIT`; do
			echo -n "."
			## Check to see how many guests are still running.
			NUM_DOMU=$((`$CMD list | wc -l`-2))
			if [ $NUM_DOMU -eq "0" ]; then
				success; echo
				break
			fi
			sleep 1
		done

		## Look for stray DomUs
		NUM_DOMU=$((`$CMD list | wc -l`-2))
		if [ $NUM_DOMU -ne "0" ]; then
			## Forcefully close any remaining DomUs
			warning; echo
			IFS=$'\n'
			for DOMU in `$CMD list | tail -n +3 | sort`; do
				unset IFS
				DOMU_NAME=`echo "$DOMU" | awk '{ print $1 }'`
				ID=`echo "$DOMU" | awk '{ print $2 }'`
				if [ -n "$ID" ]; then
					echo -n "Forcefully destroying $DOMU_NAME:"
					$CMD destroy $DOMU_NAME 2>&1 1>/dev/null &
					success; echo
				fi
			done
		fi
	fi

	rm -f $LOCKFILE
	return 0
}

status() {
	## We've already passed the test to see if Xen Dom0 is running, so here
	## we check the number of lines returned from a list command and minus
	## 2 from it (Header + Domain-0) and also some memory stats.
	NUM_DOMU=$((`$CMD list | wc -l`-2))
	MEM_FREE=`$CMD info | grep free_memory | cut -f2 -d":"`
	MEM_TOTAL=`$CMD info | grep total_memory | cut -f2 -d":"`
	echo "Xen running with $NUM_DOMU DomUs. $MEM_FREE MB of$MEM_TOTAL MB free."
	return 0
}

case "$1" in
    start)
        start
        RETVAL=$?
        ;;
    stop)
        stop
        RETVAL=$?
        ;;
    status)
        status
        RETVAL=$?
        ;;
    restart)
	stop
	start
	;;
esac

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