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Created March 5, 2015 14:27
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#!/bin/bash
#
# Script to make a proxy (ie HAProxy) capable of monitoring Percona XtraDB Cluster nodes properly
#
# Authors:
# Raghavendra Prabhu <raghavendra.prabhu@percona.com>
# Olaf van Zandwijk <olaf.vanzandwijk@nedap.com>
#
# Based on the original script from Unai Rodriguez and Olaf (https://github.com/olafz/percona-clustercheck)
#
# Grant privileges required:
# GRANT PROCESS ON *.* TO 'clustercheckuser'@'localhost' IDENTIFIED BY 'clustercheckpassword!';
if [[ $1 == '-h' || $1 == '--help' ]];then
echo "Usage: $0 <user> <pass> <available_when_donor=0|1> <log_file> <available_when_readonly=0|1> <defaults_extra_file>"
exit
fi
MYSQL_USERNAME="${1-clustercheckuser}"
MYSQL_PASSWORD="${2-clustercheckpassword!}"
MYSQL_HOST="${3-mysqlhost!}"
AVAILABLE_WHEN_DONOR=${4:-0}
ERR_FILE="${5:-/dev/null}"
AVAILABLE_WHEN_READONLY=${6:-1}
DEFAULTS_EXTRA_FILE=${7:-/etc/my.cnf}
#Timeout exists for instances where mysqld may be hung
TIMEOUT=10
if [[ -n "$MYSQL_USERNAME" ]]; then
EXTRA_ARGS="$EXTRA_ARGS --user=${MYSQL_USERNAME}"
fi
if [[ -n "$MYSQL_PASSWORD" ]]; then
EXTRA_ARGS="$EXTRA_ARGS --password=${MYSQL_PASSWORD}"
fi
if [[ -n "$MYSQL_HOST" ]]; then
EXTRA_ARGS="$EXTRA_ARGS --host=${MYSQL_HOST}"
fi
if [[ -r $DEFAULTS_EXTRA_FILE ]];then
MYSQL_CMDLINE="mysql --defaults-extra-file=$DEFAULTS_EXTRA_FILE -nNE --connect-timeout=$TIMEOUT \
${EXTRA_ARGS}"
else
MYSQL_CMDLINE="mysql -nNE --connect-timeout=$TIMEOUT ${EXTRA_ARGS}"
fi
#
# Perform the query to check the wsrep_local_state
#
WSREP_STATUS=$($MYSQL_CMDLINE -e "SHOW STATUS LIKE 'wsrep_local_state';" \
2>${ERR_FILE} | tail -1 2>>${ERR_FILE})
if [[ "${WSREP_STATUS}" == "4" ]] || [[ "${WSREP_STATUS}" == "2" && ${AVAILABLE_WHEN_DONOR} == 1 ]]
then
# Check only when set to 0 to avoid latency in response.
if [[ $AVAILABLE_WHEN_READONLY -eq 0 ]];then
READ_ONLY=$($MYSQL_CMDLINE -e "SHOW GLOBAL VARIABLES LIKE 'read_only';" \
2>${ERR_FILE} | tail -1 2>>${ERR_FILE})
if [[ "${READ_ONLY}" == "ON" ]];then
# Percona XtraDB Cluster node local state is 'Synced', but it is in
# read-only mode. The variable AVAILABLE_WHEN_READONLY is set to 0.
# => return HTTP 503
# Shell return-code is 1
echo -en "HTTP/1.1 503 Service Unavailable\r\n"
echo -en "Content-Type: text/plain\r\n"
echo -en "Connection: close\r\n"
echo -en "Content-Length: 43\r\n"
echo -en "\r\n"
echo -en "Percona XtraDB Cluster Node is read-only.\r\n"
sleep 0.1
exit 1
fi
fi
# Percona XtraDB Cluster node local state is 'Synced' => return HTTP 200
# Shell return-code is 0
echo -en "HTTP/1.1 200 OK\r\n"
echo -en "Content-Type: text/plain\r\n"
echo -en "Connection: close\r\n"
echo -en "Content-Length: 40\r\n"
echo -en "\r\n"
echo -en "Percona XtraDB Cluster Node is synced.\r\n"
sleep 0.1
exit 0
else
# Percona XtraDB Cluster node local state is not 'Synced' => return HTTP 503
# Shell return-code is 1
echo -en "HTTP/1.1 503 Service Unavailable\r\n"
echo -en "Content-Type: text/plain\r\n"
echo -en "Connection: close\r\n"
echo -en "Content-Length: 44\r\n"
echo -en "\r\n"
echo -en "Percona XtraDB Cluster Node is not synced.\r\n"
sleep 0.1
exit 1
fi
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