环境准备：
三节点PXC，部署过程见：http://blog.itpub.net/30135314/viewspace-2219505/
192.168.8.51
192.168.8.52
192.168.8.53
haproxy+keepalived
192.168.8.59
192.168.8.61
工具包版本：
percona-xtrabackup-2.4.11-Linux-x86_64.libgcrypt145.tar.gz
Percona-XtraDB-Cluster-5.7.21-rel20-29.26.1.Linux.x86_64.ssl101.tar.gz
keepalived-2.0.5.tar.gz
haproxy-1.8.9.tar.gz
本文只介绍PXC+haproxy+keepalived环境搭建过程，各个工具包安装过程略。
一、添加集群检查用户
grant process on *.* to 'clustercheckuser'@'localhost' identified by 'mysql';
flush privileges;
select user,host from mysql.user;
二、修改clustercheck脚本
#!/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="${2-mysql}"
AVAILABLE_WHEN_DONOR=${3:-0}
ERR_FILE="${4:-/dev/null}"
AVAILABLE_WHEN_READONLY=${5:-1}
DEFAULTS_EXTRA_FILE=${6:-/mysql/data/3306/my.cnf}
#Timeout exists for instances where mysqld may be hung
TIMEOUT=10
EXTRA_ARGS=""
if [[ -n "$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 [[ -r $DEFAULTS_EXTRA_FILE ]];then
MYSQL_CMDLINE="/mysql/app/mysql/bin/mysql --defaults-extra-file=$DEFAULTS_EXTRA_FILE -nNE --connect-timeout=$TIMEOUT \
${EXTRA_ARGS}"
else
MYSQL_CMDLINE="/mysql/app/mysql/bin/mysql -nNE --connect-timeout=$TIMEOUT ${EXTRA_ARGS}"
fi
#
# Perform the query to check the wsrep_local_state
#
WSREP_STATUS=($($MYSQL_CMDLINE -e "SHOW GLOBAL STATUS LIKE 'wsrep_%';" \
2>${ERR_FILE} | grep -A 1 -E 'wsrep_local_state$|wsrep_cluster_status$' \
| sed -n -e '2p' -e '5p' | tr '\n' ' '))
if [[ ${WSREP_STATUS[1]} == 'Primary' && ( ${WSREP_STATUS[0]} -eq 4 || \
( ${WSREP_STATUS[0]} -eq 2 && $AVAILABLE_WHEN_DONOR -eq 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: 57\r\n"
echo -en "\r\n"
echo -en "Percona XtraDB Cluster Node is not synced or non-PRIM. \r\n"
sleep 0.1
exit 1
fi
三、xinetd 守护进程（PXC所有节点）
mount /dev/cdrom /media
yum -y install xinetd
yum -y install telnet
echo "mysqlchk 9200/tcp #add mysqlchk" >> /etc/services
vi /etc/xinetd.d/mysqlchk
# default: on
# description: mysqlchk
service mysqlchk
{
# this is a config for xinetd, place it in /etc/xinetd.d/
disable = no
flags = REUSE
socket_type = stream
port = 9200
wait = no
user = nobody
server = /mysql/app/mysql/bin/clustercheck
log_on_failure += USERID
only_from = 0.0.0.0/0
# recommended to put the IPs that need
# to connect exclusively (security purposes)
per_source = UNLIMITED
}
chmod u+x /etc/xinetd.d/mysqlchk
从负载均衡节点测试PXC三个端口状态
[root@node2 bin]# telnet 192.168.8.51 9200
Trying 192.168.8.51...
Connected to 192.168.8.51.
Escape character is '^]'.
HTTP/1.1 200 OK
Content-Type: text/plain
Connection: close
Content-Length: 40
Percona XtraDB Cluster Node is synced.
Connection closed by foreign host.
四、配置haproxy
global
log 127.0.0.1 local0 notice
#user haproxy
#group haproxy
daemon
#quiet
nbproc 1
pidfile /usr/local/haproxy/haproxy.pid
defaults
log global
retries 3
option dontlognull
option redispatch
maxconn 2000
timeout queue 1m
timeout http-request 10s
timeout connect 10s
timeout server 1m
timeout client 1m
timeout http-keep-alive 10s
timeout check 10s
balance roundrobin
listen mysql_pxc_gwpt1_read
bind 192.168.8.98:3307
mode tcp
balance leastconn
stats hide-version
option httpchk
server node1 192.168.8.51:3306 check port 9200 inter 12000 rise 3 fall 3
server node2 192.168.8.52:3306 check port 9200 inter 12000 rise 3 fall 3
server node3 192.168.8.53:3306 check port 9200 inter 12000 rise 3 fall 3
listen mysql_pxc_gwpt1_write
bind 192.168.8.98:3308
mode tcp
balance leastconn
stats hide-version
option httpchk
server node1 192.168.8.51:3306 check port 9200 inter 12000 rise 3 fall 3
server node2 192.168.8.52:3306 check port 9200 inter 12000 rise 3 fall 3 backup
server node3 192.168.8.53:3306 check port 9200 inter 12000 rise 3 fall 3 backup
listen haproxy_stats
mode http
bind *:8888
option httplog
stats refresh 5s
stats uri /haproxy-stat
stats realm www.zdd.com moritor
stats realm Haproxy Manager
stats auth haproxy:haproxy
/etc/rc.d/init.d/haproxy stop
/etc/rc.d/init.d/haproxy start
systemctl stop keepalived
systemctl start keepalived
五、从负载均衡节点访问PXC进行测试
[root@slave2 haproxy]# mysql -uroot -pmysql -h292.168.8.98 -P3308 -e "select @@hostname;"
mysql: [Warning] Using a password on the command line interface can be insecure.
+------------+
| @@hostname |
+------------+
| node1 |
+------------+
[root@slave2 haproxy]# mysql -uroot -pmysql -h292.168.8.98 -P3308 -e "select @@hostname;"
mysql: [Warning] Using a password on the command line interface can be insecure.
+------------+
| @@hostname |
+------------+
| node1 |
+------------+
[root@slave2 haproxy]# mysql -uroot -pmysql -h292.168.8.98 -P3308 -e "select @@hostname;"
mysql: [Warning] Using a password on the command line interface can be insecure.
+------------+
| @@hostname |
+------------+
| node1 |
+------------+
[root@slave2 haproxy]# mysql -uroot -pmysql -h292.168.8.98 -P3308 -e "select @@hostname;"
mysql: [Warning] Using a password on the command line interface can be insecure.
+------------+
| @@hostname |
+------------+
| node1 |
+------------+
[root@slave2 haproxy]# mysql -uroot -pmysql -h292.168.8.98 -P3307 -e "select @@hostname;"
mysql: [Warning] Using a password on the command line interface can be insecure.
+------------+
| @@hostname |
+------------+
| node1 |
+------------+
[root@slave2 haproxy]# mysql -uroot -pmysql -h292.168.8.98 -P3307 -e "select @@hostname;"
mysql: [Warning] Using a password on the command line interface can be insecure.
+------------+
| @@hostname |
+------------+
| node2 |
+------------+
[root@slave2 haproxy]# mysql -uroot -pmysql -h292.168.8.98 -P3307 -e "select @@hostname;"
mysql: [Warning] Using a password on the command line interface can be insecure.
+------------+
| @@hostname |
+------------+
| node3 |
+------------+
[root@slave2 haproxy]# mysql -uroot -pmysql -h292.168.8.98 -P3307 -e "select @@hostname;"
mysql: [Warning] Using a password on the command line interface can be insecure.
+------------+
| @@hostname |
+------------+
| node1 |
+------------+
[root@slave2 haproxy]# mysql -uroot -pmysql -h292.168.8.98 -P3307 -e "select @@hostname;"
mysql: [Warning] Using a password on the command line interface can be insecure.
+------------+
| @@hostname |
+------------+
| node2 |
+------------+
[root@slave2 haproxy]# mysql -uroot -pmysql -h292.168.8.98 -P3307 -e "select @@hostname;"
mysql: [Warning] Using a password on the command line interface can be insecure.
+------------+
| @@hostname |
+------------+
| node3 |
+------------+
可以看到，端口3307监控的是读操作，三个节点为轮询机制，访问3308一直访问到node1，因为node2和node3为backup，只有node1宕掉时候才会被访问到。
六、查看haproxy控制台状态
http://192.168.8.98:8888/haproxy-stat
