MySQL replication monitor - Seconds_Behind_Master - mysql

Question

I'm using Nagios and the check_mysql_health plugin to monitor my MySQL databases. I need to keep an eye on my Seconds_Behind_Master values in my replicated databases, but I am unable to use SHOW SLAVE STATUS in a subquery to get at that value specifically. Does anyone know another way to get at the value of the Seconds_Behind_Master values of my slave databases as a single value? For the check_mysql_health plugin to work I need to return just a single numeric value that will be monitored.

Answer 1

#!/bin/bash
#########################################################################
# Script: check_mysql_slavestatus.sh #
# Author: Claudio Kuenzler www.claudiokuenzler.com #
# Purpose: Monitor MySQL Replication status with Nagios #
# Description: Connects to given MySQL hosts and checks for running #
# SLAVE state and delivers additional info #
# Original: This script is a modified version of #
# check mysql slave sql running written by dhirajt #
# Thanks to: Victor Balada Diaz for his ideas added on 20080930 #
# Soren Klintrup for stuff added on 20081015 #
# Marc Feret for Slave_IO_Running check 20111227 #
# Peter Lecki for his mods added on 20120803 #
# Serge Victor for his mods added on 20131223 #
# Omri Bahumi for his fix added on 20131230 #
# History: #
# 2008041700 Original Script modified #
# 2008041701 Added additional info if status OK #
# 2008041702 Added usage of script with params -H -u -p #
# 2008041703 Added bindir variable for multiple platforms #
# 2008041704 Added help because mankind needs help #
# 2008093000 Using /bin/sh instead of /bin/bash #
# 2008093001 Added port for MySQL server #
# 2008093002 Added mysqldir if mysql binary is elsewhere #
# 2008101501 Changed bindir/mysqldir to use PATH #
# 2008101501 Use $() instead of `` to avoid forks #
# 2008101501 Use ${} for variables to prevent problems #
# 2008101501 Check if required commands exist #
# 2008101501 Check if mysql connection works #
# 2008101501 Exit with unknown status at script end #
# 2008101501 Also display help if no option is given #
# 2008101501 Add warning/critical check to delay #
# 2011062200 Add perfdata #
# 2011122700 Checking Slave_IO_Running #
# 2012080300 Changed to use only one mysql query #
# 2012080301 Added warn and crit delay as optional args #
# 2012080302 Added standard -h option for syntax help #
# 2012080303 Added check for mandatory options passed in #
# 2012080304 Added error output from mysql #
# 2012080305 Changed from 'cut' to 'awk' (eliminate ws) #
# 2012111600 Do not show password in error output #
# 2013042800 Changed PATH to use existing PATH, too #
# 2013050800 Bugfix in PATH export #
# 2013092700 Bugfix in PATH export #
# 2013092701 Bugfix in getopts #
# 2013101600 Rewrite of threshold logic and handling #
# 2013101601 Optical clean up #
# 2013101602 Rewrite help output #
# 2013101700 Handle Slave IO in 'Connecting' state #
# 2013101701 Minor changes in output, handling UNKWNON situations now #
# 2013101702 Exit CRITICAL when Slave IO in Connecting state #
# 2013123000 Slave_SQL_Running also matched Slave_SQL_Running_State #
#########################################################################
# Usage: ./check_mysql_slavestatus.sh -H dbhost -P port -u dbuser -p dbpass -s connection -w integer -c integer
#########################################################################
help="\ncheck_mysql_slavestatus.sh (c) 2008-2014 GNU GPLv2 licence
Usage: check_mysql_slavestatus.sh -H host -P port -u username -p password [-s connection] [-w integer] [-c integer]\n
Options:\n-H Hostname or IP of slave server\n-P Port of slave server\n-u Username of DB-user\n-p Password of DB-user\n-s Connection name (optional, with multi-source replication)\n-w Delay in seconds for Warning status (optional)\n-c Delay in seconds for Critical status (optional)\n
Attention: The DB-user you type in must have CLIENT REPLICATION rights on the DB-server. Example:\n\tGRANT REPLICATION CLIENT on *.* TO 'nagios'#'%' IDENTIFIED BY 'secret';"
STATE_OK=0 # define the exit code if status is OK
STATE_WARNING=1 # define the exit code if status is Warning (not really used)
STATE_CRITICAL=2 # define the exit code if status is Critical
STATE_UNKNOWN=3 # define the exit code if status is Unknown
export PATH=$PATH:/usr/local/bin:/usr/bin:/bin # Set path
crit="No" # what is the answer of MySQL Slave_SQL_Running for a Critical status?
ok="Yes" # what is the answer of MySQL Slave_SQL_Running for an OK status?
for cmd in mysql awk grep [
do
if ! `which ${cmd} &>/dev/null`
then
echo "UNKNOWN: This script requires the command '${cmd}' but it does not exist; please check if command exists and PATH is correct"
exit ${STATE_UNKNOWN}
fi
done
# Check for people who need help - aren't we all nice ;-)
#########################################################################
if [ "${1}" = "--help" -o "${#}" = "0" ];
then
echo -e "${help}";
exit 1;
fi
# Important given variables for the DB-Connect
#########################################################################
while getopts "H:P:u:p:s:w:c:h" Input;
do
case ${Input} in
H) host=${OPTARG};;
P) port=${OPTARG};;
u) user=${OPTARG};;
p) password=${OPTARG};;
s) connection=\"${OPTARG}\";;
w) warn_delay=${OPTARG};;
c) crit_delay=${OPTARG};;
h) echo -e "${help}"; exit 1;;
\?) echo "Wrong option given. Please use options -H for host, -P for port, -u for user and -p for password"
exit 1
;;
esac
done
# Connect to the DB server and check for informations
#########################################################################
# Check whether all required arguments were passed in
if [ -z "${host}" -o -z "${port}" -o -z "${user}" -o -z "${password}" ];then
echo -e "${help}"
exit ${STATE_UNKNOWN}
fi
# Connect to the DB server and store output in vars
ConnectionResult=`mysql -h ${host} -P ${port} -u ${user} --password=${password} -e "show slave ${connection} status\G" 2>&1`
if [ -z "`echo "${ConnectionResult}" |grep Slave_IO_State`" ]; then
echo -e "CRITICAL: Unable to connect to server ${host}:${port} with username '${user}' and given password"
exit ${STATE_CRITICAL}
fi
check=`echo "${ConnectionResult}" |grep Slave_SQL_Running: | awk '{print $2}'`
checkio=`echo "${ConnectionResult}" |grep Slave_IO_Running: | awk '{print $2}'`
masterinfo=`echo "${ConnectionResult}" |grep Master_Host: | awk '{print $2}'`
delayinfo=`echo "${ConnectionResult}" |grep Seconds_Behind_Master: | awk '{print $2}'`
# Output of different exit states
#########################################################################
if [ ${check} = "NULL" ]; then
echo "CRITICAL: Slave_SQL_Running is answering NULL"; exit ${STATE_CRITICAL};
fi
if [ ${check} = ${crit} ]; then
echo "CRITICAL: ${host}:${port} Slave_SQL_Running: ${check}"; exit ${STATE_CRITICAL};
fi
if [ ${checkio} = ${crit} ]; then
# Checking local node replication role
# LOCAL_NODE=`hostname`
ROLE=`mysql -h $host -u slave_user -p'ZAQ!2wsx' --execute="SHOW master STATUS\G;" | grep Binlog_Do_DB | cut -d ' ' -f 6`
if [[ -n "$ROLE" ]];
then
echo "OK: This node is Master"; exit ${STATE_OK};
else
echo "CRITICAL: ${host} Slave_IO_Running: ${checkio}"; exit ${STATE_CRITICAL};
fi
fi
if [ ${checkio} = "Connecting" ]; then
echo "CRITICAL: ${host} Slave_IO_Running: ${checkio}"; exit ${STATE_CRITICAL};
fi
if [ ${check} = ${ok} ] && [ ${checkio} = ${ok} ]; then
# Delay thresholds are set
if [[ -n ${warn_delay} ]] && [[ -n ${crit_delay} ]]; then
if ! [[ ${warn_delay} -gt 0 ]]; then echo "Warning threshold must be a valid integer greater than 0"; exit $STATE_UNKNOWN; fi
if ! [[ ${crit_delay} -gt 0 ]]; then echo "Warning threshold must be a valid integer greater than 0"; exit $STATE_UNKNOWN; fi
if [[ -z ${warn_delay} ]] || [[ -z ${crit_delay} ]]; then echo "Both warning and critical thresholds must be set"; exit $STATE_UNKNOWN; fi
if [[ ${warn_delay} -gt ${crit_delay} ]]; then echo "Warning threshold cannot be greater than critical"; exit $STATE_UNKNOWN; fi
if [[ ${delayinfo} -ge ${crit_delay} ]]
then echo "CRITICAL: Slave is ${delayinfo} seconds behind Master | delay=${delayinfo}s"; exit ${STATE_CRITICAL}
elif [[ ${delayinfo} -ge ${warn_delay} ]]
then echo "WARNING: Slave is ${delayinfo} seconds behind Master | delay=${delayinfo}s"; exit ${STATE_WARNING}
else echo "OK: Slave SQL running: ${check} Slave IO running: ${checkio} / master: ${masterinfo} / slave is ${delayinfo} seconds behind master | delay=${delayinfo}s"; exit ${STATE_OK};
fi
else
# Without delay thresholds
echo "OK: Slave SQL running: ${check} Slave IO running: ${checkio} / master: ${masterinfo} / slave is ${delayinfo} seconds behind master | delay=${delayinfo}s"
exit ${STATE_OK};
fi
fi
echo "UNKNOWN: should never reach this part (Slave_SQL_Running is ${check}, Slave_IO_Running is ${checkio})"
exit ${STATE_UNKNOWN}