Apache Restart

Overview

Restarts apache if load gets above a certain threshold. Has logging and locking functionality.

Script

#!/bin/bash

#Load Threshold for doing a dump.
THRESH=20

#Number of lines to keep in log
LOGROTATE=1000

#Email Alerts
EMAILTO=""

function plog {

	echo "[ `date` ][ $LOAD ] $1" >> /var/log/apacherestart
	if [ EMAILTO ]
	then
		echo "[ `date` ][ $LOAD ] $1"
	fi

	if [ "`wc -l /var/log/apacherestart | awk '{print $1}'`" -gt "$LOGROTATE" ]
	then
		sed -i -e "1d" /var/log/apacherestart
	fi
	return
}

function restartapache {
	plog "Restarting Apache"
	echo $$ > /var/run/.apacherestart
	service httpd restart
	rm -f /var/run/.apacherestart
	plog "Apache Restart Completed"
	return
}

function enablecron {
	if [ -e "/etc/cron.d/apacherestart.sh" ]
	then
		echo "Cron already enabled, use change to set new time"
	else
		echo "What time would you like to set the cron to"
		echo "[IE: */1 * * * * ]"
		read crontime;
		if [ ! $crontime ] 
		then
			crontime="*/1 * * * *"
		fi
		echo "SHELL=/bin/bash" > /etc/cron.d/apacherestart.sh
		if [ $EMAILTO ]
		then
			echo 'MAILTO="$MAILTO"' > /etc/cron.d/apacherestart.sh
		fi
		echo "$crontime root $(readlink -f $0)" >> /etc/cron.d/apacherestart.sh
		chmod 0644 /etc/cron.d/apacherestart.sh
		echo "Cron enabled [$crontime root $(readlink -f $0)]"
		return
	fi
	return
}
 
function disablecron {
	if [ -e "/etc/cron.d/apacherestart.sh" ]
	then
		rm -f /etc/cron.d/apacherestart.sh
		echo "Cron disabled"
	else
		echo "Cron not enabled"
	fi
 	return
}

function checkload {
	LOAD=`cat /proc/loadavg | awk '{print $1}' | awk -F '.' '{print $1}'`

	if [ $LOAD -gt $THRESH ]
	then
		if [ ! -e "/var/run/.apacherestart" ]
		then
			restartapache
		else
			opid=`cat /var/run/.apacherestart`
			if [ ! "`ps ax | grep $opid | grep ${0##*/}`" ]
			then
				plog "Stale Lock File Removed"
				rm -f /var/run/.apacherestart
				restartapache
			else
				plog "Active Lock File Found"
			fi
		fi
	fi
}

case $1 in
        --cron)
                case $2 in
			on)
				enablecron
				;;
			off)
				disablecron
				;;
			change)
				disablecron
				enablecron
				;;
		esac
                ;;
        --help)
                echo "Apache Restart usage:"
		echo " --cron [on, change, off]"
		echo "	on: Turns on cron job and asks for time"
		echo "	change: Changes the cron time"
		echo "	off: Turns off the cron job"
                ;;
        *)
                checkload
                ;;
  esac

What to change

THRESH load threshold before trying to restart apache

LOGROTATE number of lines to keep in the log before rotating.