Bash – How to convert Ubuntu init script to Amazon Linux AMI init script

amazon ec2bashlinuxshellUbuntu

I had a Ubuntu based Amazon EC2 server where I was running my java based application. For this I had written a init script which was running perfectly and as follows

 #! /bin/sh
# set the environment variables that are used
PATH=/sbin:/usr/sbin:/bin:/usr/bin
JAVA_HOME=/usr/lib/jvm/java-6-sun/jre
JAVA=$JAVA_HOME/bin/java
DESC="My Application"
NAME="myserver"
DAEMON=$JAVA
DAEMON_HOME="/home/ganesh/MyServer/"
JAR=$DAEMON_HOME/MyServer.jar
DAEMON_ARGS="-Xms512m -Xmx4112m -jar $JAR"
PIDFILE=/var/run/$NAME.pid
SCRIPTNAME=/etc/init.d/myserver
#the user that will run the script
USER=ganesh

# Load the VERBOSE setting and other rcS variables
. /lib/init/vars.sh

# Define LSB log_* functions.
# Depend on lsb-base (>= 3.0-6) to ensure that this file is present.
. /lib/lsb/init-functions

#
# Function that starts the daemon/service
#
do_start()
{
        start-stop-daemon -N -10 -b --start -d $DAEMON_HOME --quiet --chuid $USER -m -p $PIDFILE --exec $DAEMON -- $DAEMON_ARGS \
                || return 2


        #Test to see if the engine has started
        start-stop-daemon -b --test --start -d $DAEMON_HOME --quiet --chuid $USER -m -p $PIDFILE --exec $DAEMON -- $DAEMON_ARGS >/dev/null 2>&1

    case "$?" in
        0) echo "[ FAIL ] App Engine has not started";;
        1) echo "[ OK ] App Engine has started";;
    esac                               
}

#
# Function that stops the daemon/service
#
do_stop()
{
        start-stop-daemon --stop --retry 120 --oknodo --pidfile $PIDFILE
        RETVAL="$?"
        rm -f $PIDFILE
        return "$RETVAL"
}

case "$1" in
  start)
        [ "$VERBOSE" != no ] && log_daemon_msg "Starting $DESC" "$NAME"
        echo "Starting $DESC" "$NAME"

        do_start
        case "$?" in
                0|1) [ "$VERBOSE" != no ] && log_end_msg 0 ;;
                2) [ "$VERBOSE" != no ] && log_end_msg 1
                                echo "[ FAIL ]";;              
        esac
        ;;

  stop)
        [ "$VERBOSE" != no ] && log_daemon_msg "Stopping $DESC" "$NAME"
        echo "Stopping $DESC" "$NAME"
        do_stop
        case "$?" in
                0|1) [ "$VERBOSE" != no ] && log_end_msg 0 ;;
                2) [ "$VERBOSE" != no ] && log_end_msg 1 ;;
        esac
        echo "[ OK ]"
        ;;
  restart)
        #
        # If the "reload" option is implemented then remove the
        # 'force-reload' alias
        #
        log_daemon_msg "Restarting $DESC" "$NAME"
        echo "Restarting $DESC" "$NAME"
        do_stop
        case "$?" in
          0|1)
                do_start
                case "$?" in
                        0) log_end_msg 0 ;;
                        1) log_end_msg 1 ;; # Old process is still running
                        *) log_end_msg 1 ;; # Failed to start
                esac
                ;;
          *)
                # Failed to stop
                log_end_msg 1
                ;;
        esac
        ;;
  *)
        echo "Usage: $SCRIPTNAME {start|stop|restart}" >&2
        exit 3
        ;;
esac

:

Now I have moved my server from Ubuntu to Amazon Linux AMI. So I have changed above init script as follows

#!/bin/bash

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

RETVAL=0
prog="myserver"
LOCKFILE=/var/lock/subsys/$prog
PIDFILE=/var/run/$prog.pid
PATH=/sbin:/usr/sbin:/bin:/usr/bin
JAVA=/usr/bin/java
DESC="MY Application"
DAEMON=$JAVA
DAEMON_HOME="/home/ganesh/MyServer"
JAR=$DAEMON_HOME/MyServer.jar
DAEMON_ARGS="-Xms512m -Xmx4112m -jar $JAR"
PIDFILE=/var/run/$NAME.pid
SCRIPTNAME=/etc/init.d/myserver
#the user that will run the script
USER=root

echo "All value sets"

start() {
        echo "IN start"
        echo -n "Starting $prog: "
        daemon --user $USER --chdir $DAEMON_HOME --pidfile $PIDFILE $DAEMON -- $DAEMON_ARGS
        RETVAL=$?
        [ $RETVAL -eq 0 ] && touch $LOCKFILE
        echo
        return $RETVAL
}

stop() {
        echo -n "Shutting down $prog: "
        killproc --pidfile
        RETVAL=$?
        [ $RETVAL -eq 0 ] && rm -f $LOCKFILE
        echo
        return $RETVAL
}

status() {
        echo -n "Checking $prog status: "
        RETVAL=$?
        return $RETVAL
}

case "$1" in
    start)
        start
        ;;
    stop)
        stop
        ;;
    status)
        status
        ;;
    restart)
        stop
        start
        ;;
    *)
        echo "Usage1: $prog {start|stop|status|restart}"
        exit 1
        ;;
esac
exit $RETVAL

I have a trouble in replacing the following main lines in start and stop functions 

start-stop-daemon -N -10 -b --start -d $DAEMON_HOME --quiet --chuid
$USER -m -p $PIDFILE --exec $DAEMON -- $DAEMON_ARGS \
              || return 2

and 

start-stop-daemon --stop --retry 120 --oknodo --pidfile $PIDFILE

Amazon Linux replaces 'start-stop-daemon' with 'daemon' and with the help of man page I have changed above lines as follows

daemon --user $USER --chdir $DAEMON_HOME --pidfile $PIDFILE $DAEMON -- $DAEMON_ARGS

and 

killproc --pidfile

But it is giving following error.

Starting myserver: ./myserver: Usage: daemon
[+/-nicelevel] {program}

Will anybody guide me to write the proper init script for Amazon Linux AMI?

EDIT:

In start function I did the following changes and now this script starts the daemon but fails to create a pidfile and hence it fails to stop the daemon

cd $DAEMON_HOME
daemon --user $USER --pidfile $PIDFILE $DAEMON $DAEMON_ARGS >/dev/null 2>&1 &

So can anyone suggest me about what is wrong in it and what i need to do so it should create pid file auomatically?

Best Answer

I updated my script to following code. Although it is not able to create pidfile but it is working as I want. If anybody has better script then kindly post your answer.

#!/bin/bash

# chkconfig: 2345 95 05
# description: MY Application

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

RETVAL=0
prog="myserver"
PIDFILE=/var/run/$prog.pid
LOCKFILE=/var/lock/subsys/$prog
PATH=/sbin:/usr/sbin:/bin:/usr/bin
JAVA=/usr/bin/java
DESC="MY Application"
DAEMON=$JAVA
DAEMON_HOME="/home/ganesh/MyServer/"
JAR=$DAEMON_HOME/MyServer.jar
DAEMON_ARGS="-Xms512m -Xmx4112m -jar $JAR"
SCRIPTNAME=/etc/init.d/myserver
#the user that will run the script
USER=root

#echo "All value sets"

start() {
    if [ -f $LOCKFILE ];
    then
        echo "$DESC is already running. Exiting."
        exit 1
    else
        echo -n "Starting $prog:"
        cd $DAEMON_HOME
        daemon --user $USER  --pidfile $PIDFILE $DAEMON $DAEMON_ARGS >/dev/null 2>&1 &
        RETVAL=$?
        echo
        [ $RETVAL -eq 0 ] && touch $LOCKFILE
    fi

    return $RETVAL
}

stop() {
        echo -n "Shutting down "$prog:
        kill -9  `ps -ef | grep "$JAR" | grep -v grep | awk '{ print $2 }'`        
        RETVAL=$?
        echo
        [ $RETVAL -eq 0 ] && rm -f $LOCKFILE
        return $RETVAL
}

check_status() {
        #echo -n "Checking $prog status: "
        status $prog
        RETVAL=$?
        return $RETVAL
}

case "$1" in
    start)
        start
        ;;
    stop)
        stop
        ;;
    status)
        check_status
        ;;
    restart)
        stop
        start
        ;;
    *)

        echo "Usage: $prog {start|stop|status|restart}"
        exit 1
        ;;
esac
exit $RETVAL

EDIT:

Another Version of above script where I am creating pid file and using it to get status and stop the application. I think the following script is more reliable than above.

#!/bin/bash

# chkconfig: 2345 95 05
# description: MY Application

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

RETVAL=0
prog="myserver"
PIDFILE=/var/run/$prog.pid
LOCKFILE=/var/lock/subsys/$prog
PATH=/sbin:/usr/sbin:/bin:/usr/bin
JAVA=/usr/bin/java
DESC="MY Application"
DAEMON=$JAVA
DAEMON_HOME="/home/ganesh/MyServer/"
JAR=$DAEMON_HOME/MyServer.jar
DAEMON_ARGS="-Xms512m -Xmx4112m -jar $JAR"
SCRIPTNAME=/etc/init.d/myserver
#the user that will run the script
USER=root

#echo "All value sets"

start() {
    if [ -f $PIDFILE ]; then
        PID=`cat $PIDFILE`
        if [ -z "`pgrep $PID`" ] && [ "$PID" != "`ps aux|grep -vE 'grep|runuser|bash'|grep -w "$JAR"|awk '{print $2}'`" ]; then
            printf "%s\n" "Process dead but pidfile exists"
        else
            printf "$prog is already running!\n"
        fi
    else
        printf "%-50s" "Starting $prog ..."
        cd $DAEMON_HOME
        daemon --user $USER $DAEMON $DAEMON_ARGS >/dev/null 2>&1 &
        sleep 5
        PID=`ps aux|grep -vE 'grep|runuser|bash'|grep -w "$JAR"|awk '{print $2}'`
        if [ -z "$PID" ]; then
            printf "[ \e[31mFAIL\033[0m ]\n"
        else
            echo $PID > $PIDFILE
            printf "[ \e[32mOK\033[0m ]\n"
        fi
    fi
}

stop() {
    printf "%-50s" "Shutting down $prog:"
    if [ -f $PIDFILE ]; then
        PID=`cat $PIDFILE`
        kill -HUP $PID 2>/dev/null
        printf "[ \e[32mOK\033[0m ]\n"
        rm -f $PIDFILE
    else
        printf "[ \e[31mFAIL\033[0m ]\n" 
    fi
}

check_status() {
    printf "%-50s" "Checking $prog ..."
    if [ -f $PIDFILE ]; then
        PID=`cat $PIDFILE`
        if [ -z "`pgrep $PID`" ] && [ "$PID" != "`ps aux|grep -vE 'grep|runuser|bash'|grep -w "$JAR"|awk '{print $2}'`" ]; then
            printf "%s\n" "Process dead but pidfile exists"
        else
            printf "[ \e[32mRUNNING\033[0m ]\n"
        fi
    else
        printf "[ \e[31mSTOPPED\033[0m ]\n"
    fi
}

case "$1" in
    start)
        start
        ;;
    stop)
        stop
        ;;
    status)
        check_status
        ;;
    restart)
        stop
        start
        ;;
    *)
        echo "Usage: $prog {start|stop|status|restart}"
        exit 1
        ;;
esac
exit 1
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