not to run duplicate instances of service - linux

Question

I am writing a init.d script for kibana
as of not script is running partially, but the issue is if I run run service kibana start even if service is running then second instance start which bothers me I want to add check before starting service, if service is running then dont start second instance. I tried to put if check on "/var/lock/subsys/kibana" but didn't work. Here is my script :
#!/bin/bash
KIBANA_PATH="/opt/kibana4"
DESC="Kibana Daemon"
NAME=kibana
DAEMON=bin/kibana
CONFIG_DIR=$KIBANA_PATH/config/kibana.yml
LOGFILE=/var/log/kibana/kibana.log
#ARGS="agent --config ${CONFIG_DIR} --log ${LOGFILE}"
SCRIPTNAME=/etc/init.d/kibana
PIDFILE=/var/run/kibana.pid
base=kibana
# Exit if the package is not installed
if [ ! -x "$KIBANA_PATH/$DAEMON" ]; then
{
echo "Couldn't find $DAEMON"
exit 99
}
fi
. /etc/init.d/functions
#
# Function that starts the daemon/service
#
do_start()
{
cd $KIBANA_PATH && \
($DAEMON >> $LOGFILE &) && \
success || failure;
}
set_pidfile()
{
pgrep -f "kibana.jar" > $PIDFILE
}
#
# Function that stops the daemon/service
#
do_stop()
{
pid=`cat $PIDFILE`
if checkpid $pid 2>&1; then
# TERM first, then KILL if not dead
kill -TERM $pid >/dev/null 2>&1
usleep 100000
if checkpid $pid && sleep 1 &&
checkpid $pid && sleep $delay &&
checkpid $pid ; then
kill -KILL $pid >/dev/null 2>&1
usleep 100000
fi
fi
checkpid $pid
RC=$?
[ "$RC" -eq 0 ] && failure $"$base shutdown" || success $"$base shutdown"
}
case "$1" in
start)
echo -n "Starting $DESC: "
do_start
touch /var/lock/subsys/$NAME
set_pidfile
;;
stop)
echo -n "Stopping $DESC: "
do_stop
rm /var/lock/subsys/$NAME
rm $PIDFILE
;;
restart|reload)
echo -n "Restarting $DESC: "
do_stop
do_start
touch /var/lock/subsys/$NAME
set_pidfile
;;
status)
echo $DESC
status -p $PIDFILE
echo $!
;;
*)
echo "Usage: $SCRIPTNAME {start|stop|status|restart}" >&2
exit 3
;;
esac
echo
exit 0
any help here ?
Thanks

Answer 1

use lockfile -r0 /path/to/lock/file.lck when you start the service. every new access then will retry zero times to create the file. so if that command fails do nothing or start the service otherwise.
lockfile -r0 /path/to/lock/file.lck
if [ "$?" == "0" ]; then
echo "lock does not exist. enter devils land :)"
fi

Answer 2

The following is a pretty standard implementation of this feature used by most init.d scripts.
start () {
[ -d /var/run/nscd ] || mkdir /var/run/nscd
[ -d /var/db/nscd ] || mkdir /var/db/nscd
echo -n $"Starting $prog: "
daemon /usr/sbin/nscd $NSCD_OPTIONS
RETVAL=$?
echo
[ $RETVAL -eq 0 ] && touch /var/lock/subsys/nscd
return $RETVAL
}
...
# See how we were called.
case "$1" in
start)
[ -e /var/lock/subsys/nscd ] || start
RETVAL=$?
;;
...