Binary Talks

Update 1.3: Apache check plugin for Nagios

09.08.09 | 8 Comments

Long time no see. Sorry for the long downtime, but I’ve been on vacation for quite some time and spent my time out of reach of any electronical device except my phone. Anyway, strength and motivation for work during spare time is back again! Expect a few updates of various plugins I’ve written in the past within the next weeks.

For the beginning here’s the revised version of the Apache check plugin for Nagios. It now doesn’t write temporary files anymore, the code is cleaner and it should be a bit faster. Note that I haven’t done much testing for now (will be done tomorrow and on Wednesday). Therefore it might won’t work out of the box for you. At least in my environments it works well. Let me know if you have any problems or if you stumble upon something which is completely nonsense.

Copy’n'paste below or svn co via svn.matejunkie.com/nagios-plugins/trunk/check_apache/.

#!/bin/sh
 
#   This program is free software; you can redistribute it and/or modify
#   it under the terms of the GNU General Public License as published by
#   the Free Software Foundation; either version 2 of the License, or
#   (at your option) any later version.
#
#   This program is distributed in the hope that it will be useful,
#   but WITHOUT ANY WARRANTY; without even the implied warranty of
#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#   GNU General Public License for more details.
#
#   You should have received a copy of the GNU General Public License
#   along with this program; if not, write to the Free Software
#   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 
PROGNAME=`basename $0`
VERSION="Version 1.3,"
AUTHOR="2009, Mike Adolphs (http://www.matejunkie.com/)"
 
print_version() {
    echo "$VERSION $AUTHOR"
}
 
print_help() {
    print_version $PROGNAME $VERSION
    echo ""
    echo "Description:"
    echo "$PROGNAME is a Nagios plugin to check the Apache's server status."
    echo "It monitors requests per second, bytes per second/request, "
    echo "amount of busy/idle workers and its CPU load."
    echo ""
    echo "Example call:"
    echo "./$PROGNAME -H localhost -P 80 -t 3 -b /usr/sbin -p /var/run \\"
    echo "-n apache2.pid -s status_page [-S] [-R] [-wr] 100 [-cr] 250"
    echo ""
    echo "Options:"
    echo "  -H|--hostname)"
    echo "    Sets the hostname. Default is: localhost"
    echo "  -P|--port)"
    echo "    Sets the port. Default is: 80"
    echo "  -t|--timeout)"
    echo "    Sets a timeout within the server's status page must've been"
    echo "    accessed. Otherwise the check will go into an error state."
    echo "    Default is: 3"
    echo "  -b|--binary-path)"
    echo "    Sets the path to the apache binary. Used for getting Apache's"
    echo "    CPU load. Default is: /usr/sbin"
    echo "  -p|--pid-path)"
    echo "    Path to Apache's pid file. Default is: /var/run"
    echo "  -n|--pid-name)"
    echo "    Name of Apache's pid file. Default is: apache2.pid"
    echo "  -s|--status-page)"
    echo "    Defines the name of the status page. Default is: server-status"
    echo "  -R|--remote-server)"
    echo "    Disabled the pid check so that remote Apaches can be queried."
    echo "    Default is: off"
    echo "  -S|--secure)"
    echo "    Enables HTTPS (no certificate check though). Default is: off"
    echo "  -wr|--warning-req)"
    echo "    Sets a warning level for requests per second. Default is: off"
    echo "  -cr|--critical-req)"
    echo "    Sets a critical level for requests per second. Default is: off"
    exit $ST_UK
}
 
ST_OK=0
ST_WR=1
ST_CR=2
ST_UK=3
 
hostname="localhost"
port=80
remote_srv=0
path_binary="/usr/sbin"
path_pid="/var/run"
name_pid="apache2.pid"
status_page="server-status"
timeout=3
secure=0
running=0
 
wcdiff_req=0
wclvls_req=0
 
while test -n "$1"; do
    case "$1" in
        --help|-h)
            print_help
            exit $ST_UK
            ;;
        --version|-v)
            print_version $PROGNAME $VERSION
            exit $ST_UK
            ;;
        --hostname|-H)
            hostname=$2
            shift
            ;;
        --port|-P)
            port=$2
            shift
            ;;
        --timeout|-t)
            timeout=$2
            shift
            ;;
        --remote-server|-R)
            remote_srv=1
            ;;
        --binary_path|-b)
            path_binary=$2
            shift
            ;;
        --pid_path|-p)
            path_pid=$2
            shift
            ;;
        --pid_name|-n)
            name_pid=$2
            shift
            ;;
        --status-page|-s)
            status_page=$2
            shift
            ;;
        --secure|-S)
            secure=1
            ;;
        --warning-req|-wr)
            warn_req=$2
            shift
            ;;
        --critical-req|-cr)
            crit_req=$2
            shift
            ;;
        *)
            echo "Unknown argument: $1"
            print_help
            exit $ST_UK
            ;;
    esac
    shift
done
 
# check functions
val_wcdiff_req() {
    if [ ! -z "$warn_req" -a ! -z "$crit_req" ]
    then
        wclvls_req=1
 
        if [ ${warn_req} -gt ${crit_req} ]
        then
            wcdiff_req=1
        fi
    elif [ ! -z "$warn_req" -a -z "$crit_req" ]
    then
        wcdiff_req=2
    elif [ -z "$warn_req" -a ! -z "$crit_req" ]
    then
        wcdiff_req=3
    fi
}
 
check_pid() {
    if [ -f "$path_pid/$name_pid" ]
    then
        retval=0
    else
        retval=1
    fi
}
 
check_processes() {
    if [ $1 -lt 1 ]
    then
        echo "UNKNOWN - Your Apache server seems not to run. Is your Nagios \
privileged to run 'ps ax' and is the Apache2 binary really located in \
$path_binary?"
        exit $ST_UK
    fi
}
 
check_output() {
    stat_output=`stat -c %s ${output_dir}/server-status`
    if [ "$stat_output" = 0 ]
    then
        echo "UNKNOWN - Local copy of server-status is empty. Are we \
allowed to access http://${hostname}:${port}/server-status?"
        exit $ST_UK
    fi
}
 
# get functions
get_status() {
    if [ "$secure" = 1 ]
    then
        server_status1=`wget -qO- --no-check-certificate -t 3 \
-T ${timeout} https://${hostname}:${port}/${status_page}?auto`
    sleep 1
        server_status2=`wget -qO- --no-check-certificate -t 3 \
-T ${timeout} https://${hostname}:${port}/${status_page}?auto`
    else
        server_status1=`wget -qO- -t 3 -T ${timeout} \
http://${hostname}:${port}/${status_page}?auto`
        sleep 1
        server_status2=`wget -qO- -t 3 -T ${timeout} \
http://${hostname}:${port}/${status_page}?auto`
    fi
}
 
get_vals() {
    cpu_load="$(cpu_load=0; ps -Ao pcpu,args | grep "$path_binary/apache2" \
| awk '{print $1}' | while read line
    do
        cpu_load=`echo "scale=3; $cpu_load + $line" | bc -l`
    echo $cpu_load
    done)"
    cpu_load=`echo $cpu_load | awk '{print $NF}' | sed 's/^\./0./'`
 
    tmp1_req_psec=`echo ${server_status1} | awk '{print $3}'`
    tmp2_req_psec=`echo ${server_status2} | awk '{print $3}'`
    req_psec=`echo "scale=2; ${tmp2_req_psec} - ${tmp1_req_psec}" | bc -l \
| sed 's/^\./0./'`
 
    bytes_psec=`echo ${server_status1} | awk '{print $14}' | sed 's/^\./0./'`
    bytes_preq=`echo ${server_status1} | awk '{print $16}' | sed 's/^\./0./'`
    wkrs_busy=`echo ${server_status1} | awk '{print $18}' | sed 's/^\./0./'`
    wkrs_idle=`echo ${server_status1} | awk '{print $20}' | sed 's/^\./0./'`
}
 
do_output() {
    output="Apache serves $req_psec Requests per second with an average CPU \
utilization of $cpu_load%. Busy workers: $wkrs_busy, idle: $wkrs_idle"
}
 
do_perfdata() {
    perfdata="'cpu_load'=$cpu_load 'req_psec'=$req_psec \
'bytes_psec'=$bytes_psec 'bytes_preq'=$bytes_preq 'workers_busy'=$wkrs_busy \
'workers_idle'=$wkrs_idle"
}
 
# Let's go
val_wcdiff_req
 
if [ "$wcdiff_req" = 1 ]
then
    echo "Please adjust your warning/critical thresholds. The warning must \
be lower than the critical level!"
    exit $ST_UK
elif [ "$wcdiff_req" = 2 ]
then
    echo "Please also set a critical value when you want to use \
warning/critical thresholds!"
    exit $ST_UK
elif [ "$wcdiff_req" = 3 ]
then
    echo "Please also set a warning value when you want to use \
warning/critical thresholds!"
    exit $ST_UK
else
    if [ "$remote_srv" = 0 ]
    then
        running=`check_pid`
        check_pid $running
    fi
 
    get_status
    get_vals
 
    do_output
    do_perfdata
 
    if [ ${wclvls_req} = 1 ]
    then
        if [ ${req_psec} -ge ${warn_req} -a ${req_psec} -lt ${crit_req} ]
        then
            echo "WARNING - ${output} | ${perfdata}"
            exit $ST_WR
        elif [ ${req_psec} -ge ${crit_req} ]
        then
            echo "CRITICAL - ${output} | ${perfdata}"
        exit $ST_CR
        else
            echo "OK - ${output} | ${perfdata}"
            exit $ST_OK
        fi
    else
        echo "OK - ${output} | ${perfdata}"
        exit $ST_OK
    fi
fi
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