#!/bin/sh # ######################################################################## # This program is part of $PROJECT_NAME$ # License: GPL License (see COPYING) # Authors: # Baron Schwartz # ######################################################################## # ######################################################################## # Redirect STDERR to STDOUT; Nagios doesn't handle STDERR. # ######################################################################## exec 2>&1 # ######################################################################## # Set up constants, etc. # ######################################################################## STATE_OK=0 STATE_WARNING=1 STATE_CRITICAL=2 STATE_UNKNOWN=3 STATE_DEPENDENT=4 # ######################################################################## # Run the program. # ######################################################################## main() { # Get options for o; do case "${o}" in -c) shift; OPT_CRIT="${1}"; shift; ;; --defaults-file) shift; OPT_DEFT="${1}"; shift; ;; -H) shift; OPT_HOST="${1}"; shift; ;; -l) shift; OPT_USER="${1}"; shift; ;; -L) shift; OPT_LOPA="${1}"; shift; ;; -p) shift; OPT_PASS="${1}"; shift; ;; -P) shift; OPT_PORT="${1}"; shift; ;; -S) shift; OPT_SOCK="${1}"; shift; ;; -w) shift; OPT_WARN="${1}"; shift; ;; --version) grep -A2 '^=head1 VERSION' "$0" | tail -n1; exit 0 ;; --help) perl -00 -ne 'm/^ Usage:/ && print' "$0"; exit 0 ;; -*) echo "Unknown option ${o}. Try --help."; exit 1; ;; esac done if [ -e '/etc/nagios/mysql.cnf' ]; then OPT_DEFT="${OPT_DEFT:-/etc/nagios/mysql.cnf}" fi if is_not_sourced; then if [ -n "$1" ]; then echo "WARN spurious command-line options: $@" exit 1 fi fi # Set the exit status in case there are any problems. NOTE="UNK could not determine the PID file location." # Set up files to hold one or more PID file locations. local TEMP=$(mktemp -t "${0##*/}.XXXXXX") || exit $? local FILES=$(mktemp -t "${0##*/}.XXXXXX") || exit $? trap "rm -f '${TEMP}' '${FILES}' >/dev/null 2>&1" EXIT # If any connection option was given, then try to log in to find the PID # file. if [ "${OPT_DEFT}${OPT_HOST}${OPT_USER}${OPT_PASS}${OPT_PORT}${OPT_SOCK}" ]; then # If this fails (e.g. we can't log in), then there will be no line in the # file, and later we won't change the exit code / note away from "UNK". if mysql_exec "SHOW GLOBAL VARIABLES" > "${TEMP}"; then get_pidfile "${TEMP}" >> "${FILES}" fi else # Find all MySQL server instances. for pid in $(_pidof mysqld); do ps -p ${pid} -o pid,command | grep "${pid}" >> "${TEMP}" done # The ${TEMP} file may now contain lines like the following sample: # 13822 /usr/sbin/mysqld --defaults-file=/var/lib/mysql/my.cnf \ # --basedir=/usr --datadir=/var/lib/mysql/data/ \ # --pid-file=/var/run/mysqld/mysqld.pid \ # --socket=/var/run/mysqld/mysqld.sock # Now the task is to read find any reference to a --pid-file or --pid_file option. # We store these into the $FILES temp file. while read pid command; do if echo "${command}" | grep pid.file >/dev/null 2>&1; then # Strip off everything up to and including --pid-file= command="${command##*--pid?file=}" # Strip off any options that follow this, assuming that there's not # a space followed by a dash in the pidfile's path. echo "${command%% -*}" >> "${FILES}" fi done < "${TEMP}" fi # TODO: maybe in the future we can also check whether the PID in the file is # correct. TODO: maybe we should also alert on which PID is missing its # pidfile. MISSING="" NOTE2="" while read pidfile; do if [ ! -e "${pidfile}" ]; then MISSING=1 NOTE2="${NOTE2:+${NOTE2}; }missing ${pidfile}" fi NOTE="OK all PID files exist." done < "${FILES}" if [ "${MISSING}" ]; then if [ "${OPT_CRIT}" ]; then NOTE="CRIT ${NOTE2}" else NOTE="WARN ${NOTE2}" fi fi echo $NOTE } # ######################################################################## # Execute a MySQL command. # ######################################################################## mysql_exec() { mysql ${OPT_DEFT:+--defaults-file="${OPT_DEFT}"} \ ${OPT_LOPA:+--login-path="${OPT_LOPA}"} \ ${OPT_HOST:+-h"${OPT_HOST}"} ${OPT_PORT:+-P"${OPT_PORT}"} \ ${OPT_USER:+-u"${OPT_USER}"} ${OPT_PASS:+-p"${OPT_PASS}"} \ ${OPT_SOCK:+-S"${OPT_SOCK}"} -ss -e "$1" } # ######################################################################## # A wrapper around pidof, which might not exist. The first argument is the # command name to match. # ######################################################################## _pidof() { if ! pidof "${1}" 2>/dev/null; then ps axo pid,ucomm | awk -v comm="${1}" '$2 == comm { print $1 }' fi } # ######################################################################## # Unfortunately, MySQL 5.0 doesn't have a system variable @@pid_file, so # we have to use SHOW VARIABLES and a temp file. In 5.1 and newer we # could have done it in a single SQL statement: # SELECT IF(@@pid_file LIKE '/%', @@pid_file, # CONCAT(@@basedir, @@pid_file))" >> "${FILES}" # The first argument is the file that contains SHOW VARIABLES. # ######################################################################## get_pidfile() { awk ' /^pid_file/ { pid_file = $2 } /^basedir/ { basedir = $2 } END { if ( substr(pid_file, 1, 1) != "/" ) { pid_file = basedir pid_file; } print pid_file; } ' "$1" } # ######################################################################## # Determine whether this program is being executed directly, or sourced/included # from another file. # ######################################################################## is_not_sourced() { [ "${0##*/}" = "pmp-check-mysql-pidfile" ] || [ "${0##*/}" = "bash" -a "$_" = "$0" ] } # ######################################################################## # Execute the program if it was not included from another file. # This makes it possible to include without executing, and thus test. # ######################################################################## if is_not_sourced; then OUTPUT=$(main "$@") EXITSTATUS=$STATE_UNKNOWN case "${OUTPUT}" in UNK*) EXITSTATUS=$STATE_UNKNOWN; ;; OK*) EXITSTATUS=$STATE_OK; ;; WARN*) EXITSTATUS=$STATE_WARNING; ;; CRIT*) EXITSTATUS=$STATE_CRITICAL; ;; esac echo "${OUTPUT}" exit $EXITSTATUS fi # ############################################################################ # Documentation # ############################################################################ : <<'DOCUMENTATION' =pod =head1 NAME pmp-check-mysql-pidfile - Alert when the mysqld PID file is missing. =head1 SYNOPSIS Usage: pmp-check-mysql-pidfile [OPTIONS] Options: -c CRIT Critical threshold; makes a missing PID file critical. --defaults-file FILE Only read mysql options from the given file. Defaults to /etc/nagios/mysql.cnf if it exists. -H HOST MySQL hostname. -l USER MySQL username. -L LOGIN-PATH Use login-path to access MySQL (with MySQL client 5.6). -p PASS MySQL password. -P PORT MySQL port. -S SOCKET MySQL socket file. -w WARN Warning threshold; ignored. --help Print help and exit. --version Print version and exit. Options must be given as --option value, not --option=value or -Ovalue. Use perldoc to read embedded documentation with more details. =head1 DESCRIPTION This Nagios plugin checks to make sure that the MySQL PID file is not missing. The PID file contains the process ID of the MySQL server process, and is used by init scripts to start and stop the server. If it is deleted for some reason, then it is likely that the init script will not work correctly. The file can be deleted by poorly written scripts, an accident, or a mistaken attempt to restart MySQL while it is already running, especially if mysqld is executed directly instead of using the init script. The plugin accepts the -w and -c options for compatibility with standard Nagios plugin conventions, but they are not based on a threshold. Instead, the plugin raises a warning by default, and if the -c option is given, it raises an error instead, regardless of the option. By default, this plugin will attempt to detect all running instances of MySQL, and verify the PID file's existence for each one. It does this purely by examining the Unix process table with the C tool. However, in some cases the process's command line does not list the path to the PID file. If the tool fails to detect the MySQL server process, or if you wish to limit the check to a single instance in the event that there are multiple instances on a single server, then you can specify MySQL authentication options. This will cause the plugin to skip examining the Unix processlist, log into MySQL, and examine the pid_file variable from SHOW VARIABLES to find the location of the PID file. =head1 PRIVILEGES This plugin executes the following commands against MySQL: =over =item * C