HAProxy介绍
反向代理服务器,支持双机热备支持虚拟主机,但其配置简单,拥有非常不错的服务器健康检查功能,当其代理的后端服务器出现故障, HAProxy会自动将该服务器摘除,故障恢复后再自动将该服务器加入｡引入了frontend,backend；frontend根据任意 HTTP请求头内容做规则匹配,然后把请求定向到相关的backend.
Keepalived介绍
Keepalived是一个基于VRRP协议来实现的WEB 服务高可用方案，可以利用其来避免单点故障。一个WEB服务至少会有2台服务器运行Keepalived，一台为主服务器（MASTER），一台为备份服务器（BACKUP），但是对外表现为一个虚拟IP，主服务器会发送特定的消息给备份服务器，当备份服务器收不到这个消息的时候，即主服务器宕机的时候，备份服务器就会接管虚拟IP，继续提供服务，从而保证了高可用性。
环境情况：
OS：CentOS release 6.6 x86_64系统
MySQL版本 ：Percona-XtraDB-Cluster-5.6.22-25.8
pxc三个节点 :192.168.79.3:3306、192.168.79.4:3306、192.168.79.5:3306
HAPproxy节点 ：192.168.79.128 、 192.168.79.5
HAproxy版本 ：1.5.2
keepalived版本：keepalived-1.2.13-4.el6.x86_64 vip：192.168.79.166
一、PXC环境的搭建
配置服务器ssh登录无密码验证
ssh-keygen实现四台主机之间相互免密钥登录，保证四台主机之间能ping通
1)在所有的主机上执行：
# ssh-keygen -t rsa
2)将所有机子上公钥（id_rsa.pub）导到一个主机的/root/.ssh/authorized_keys文件中,然后将authorized_keys分别拷贝到所有主机上
cat /root/.ssh/id_rsa.pub >> /root/.ssh/authorized_keys
ssh 192.168.79.4 cat /root/.ssh/id_rsa.pub >> /root/.ssh/authorized_keys
ssh 192.168.79.5 cat /root/.ssh/id_rsa.pub >> /root/.ssh/authorized_keys
scp /root/.ssh/authorized_keys 192.168.79.4:/root/.ssh/authorized_keys
scp /root/.ssh/authorized_keys 192.168.79.5:/root/.ssh/authorized_keys
测试：ssh xxxxx date
在所有的节点上pxc所需安装软件包
# rpm -ivh perl-DBD-MySQL-4.013-3.el6.x86_64.rpm
# rpm -ivh perl-IO-Socket-SSL-1.31-2.el6.noarch.rpm
# rpm -ivh nc-1.84-22.el6.x86_64.rpm
# rpm -ivh socat-1.7.2.4-1.el6.rf.x86_64.rpm
# rpm -ivh mysql-libs-5.1.73-3.el6_5.x86_64.rpm
# rpm -ivh zlib-1.2.3-29.el6.x86_64.rpm
# rpm -ivh zlib-devel-1.2.3-29.el6.x86_64.rpm
# rpm -ivh percona-release-0.1-3.noarch.rpm
# rpm -ivh perl-Time-HiRes-1.9721-136.el6.x86_64.rpm
# rpm -ivh percona-xtrabackup-2.2.9-5067.el6.x86_64.rpm
ps:安装epel用网络yum源。yum localinstall xx.rpm解决本地包依赖
在所有的节点上mysql用户，用户组，
# groupadd mysql
# useradd mysql -g mysql -s /sbin/nologin -d /opt/mysql
解压Percona-XtraDB-Cluster二进制安装包，安装文件放在/opt/mysql,并对解压后的mysql目录加一个符号连接，mysql，这样读mysql目录操作会更方便
# cd /opt/mysql
# tar -zxvf Percona-XtraDB-Cluster-5.6.22-rel72.0-25.8.978.Linux.x86_64.tar.gz
#cd /usr/local
# ln -s /opt/mysql/Percona-XtraDB-Cluster-5.6.22-rel72.0-25.8.978.Linux.x86_64 mysql
#chown -R mysql:mysql /usr/local/mysql/
# ln -sf /usr/lib64/libssl.so.10 /usr/lib64/libssl.so.6
# ln -sf /usr/lib64/libcrypto.so.10 /usr/lib64/libcrypto.so.6
创建安装mysql的目标，并赋予权限
# mkdir -p /data/mysql/mysql_3306/{data,logs,tmp}
chown -R mysql:mysql /data/mysql/
chown -R mysql:mysql /usr/local/mysql/
加环境变量,解决找不到mysql命令的问题
echo 'export PATH=$PATH:/usr/local/mysql/bin' >> /etc/profile
source /etc/profile
echo 'export PATH=$PATH:/usr/local/mysql/bin' >> /etc/bashrc //装mhs写到这里，perl只能调用/root/.bashrc或者/etc/bashrc
my.cnf关键参数配置
###############################
# Percona XtraDB Cluster
default_storage_engine = InnoDB
#innodb_locks_unsafe_for_binlog = 1
innodb_autoinc_lock_mode = 2
wsrep_cluster_name = pxc_taotao #Cluster 集群的名字
wsrep_cluster_address = gcomm://192.168.79.3,192.168.79.4,192.168.79.5 #Cluster集群中的所有节点IP
wsrep_node_address = 192.168.79.3 #Cluster 集群当前节点的IP
wsrep_provider = /usr/local/mysql/lib/libgalera_smm.so
#wsrep_provider_options="gcache.size = 1G;debug = yes"
wsrep_provider_options="gcache.size = 1G;"
#wsrep_sst_method = rsync //很大，上T用这个
wsrep_sst_method = xtrabackup-v2 // 100-200G用
wsrep_sst_auth = sst:taotao
#wsrep_sst_donor = #从那个节点主机名同步数据
###############################333333
scp /etc/my.cnf 192.168.79.4:/etc/my.cnf
scp /etc/my.cnf 192.168.79.5:/etc/my.cnf
注：不同机子需要修改这两个参数
wsrep_node_address 参数为Cluster集群节点的当前机器的IP地址
server-id 的标识
在第一个节点上初始化数据库，启动集群第一个节点，配置备份用户
1）在第一个节点的basedir下初始化数据库：
# /usr/local/mysql/scripts/mysql_install_db --datadir=/data/mysql/mysql_3306/data --basedir=/usr/local/mysql
2）启动集群的第一个节点：
# cp /usr/local/mysql/support-files/mysql.server /etc/init.d/mysqld
# /etc/init.d/mysqld bootstrap-pxc
Bootstrapping PXC (Percona XtraDB Cluster)Starting MySQL (Percona XtraDB Cluster)................[ OK ]
# ps -ef |grep mysqld
root 8114 1 0 13:11 pts/1 00:00:00 /bin/sh /usr/local/mysql/bin/mysqld_safe --datadir=/data/mysql/mysql_3306/data --pid-file=/data/mysql/mysql_3306/data/node1.localdomain.pid --wsrep-new-cluster
mysql 9326 8114 28 13:11 pts/1 00:00:15 /usr/local/mysql/bin/mysqld --basedir=/usr/local/mysql --datadir=/data/mysql/mysql_3306/data --plugin-dir=/usr/local/mysql/lib/mysql/plugin --user=mysql --wsrep-provider=/usr/local/mysql/lib/libgalera_smm.so --wsrep-new-cluster --log-error=/data/mysql/mysql_3306/logs/error.log --pid-file=/data/mysql/mysql_3306/data/node1.localdomain.pid --socket=/tmp/mysql.sock --port=3306 --wsrep_start_position=00000000-0000-0000-0000-000000000000:-1
root 9435 6397 2 13:12 pts/1 00:00:00 grep mysqld
3）配置备份用户
# mysql
delete from mysql.user where user != 'root' or host != 'localhost';
truncate mysql.db;
drop database test;
grant all privileges on *.* to 'sst'@'localhost' identified by 'taotao'; //这一个就可以啦，供本地的innobackupex使用的
flush privileges;
其他集群节点启动：
其它节点无需初始化数据库，数据会从第一个节点上拉过来
cp /usr/local/mysql/support-files/mysql.server /etc/init.d/mysqld
# /etc/init.d/mysqld start
查看集群状态：
> show global status like 'wsrep%';
二、Haproxy负载均衡
PXC安装完成后，我们采用HARPOXY分发连接对数据库进行访问
如下在192.168.79.128 和192.168.79.5上haprox的安装配置操作，两个服务器上操作一样
1、安装haproxy(如果安装在pxc mysql节点注意端口号)
#tar -zxvf haproxy-1.5.2.tar.gz
#cd haproxy-1.5.2
#make TARGET=linux2628
#make install
ps：默认安装到/usr/local/sbin/下面，可以用PREFIX指定软件安装路径
也可以直接使用yum安装：yum install –y haproxy
2、在haproxy服务器上安装配置HAproxy
1）/etc/haproxy/haproxy.cfg配置如下：
#mkdir /etc/haproxy
# cp examples/haproxy.cfg /etc/haproxy/
# cat /etc/haproxy/haproxy.cfg
global
log 127.0.0.1 local0
log 127.0.0.1 local1 notice
maxconn 4096
#ulimit-n 10240
#chroot /usr/share/haproxy
uid 99
gid 99
daemon
#nbproc
#pidfile /var/run/haproxy/haproxy.pid
#stats socket /var/run/haproxy/haproxy.sock level operator
#debug
#quiet
defaults
log global
mode http
option tcplog
option dontlognull
retries 3
option redispatch
maxconn 2000
timeout connect 50000
timeout client 50000
timeout server 50000
frontend stats-front
bind *:8088
mode http
default_backend stats-back
frontend pxc-front
bind *:3307
mode tcp
default_backend pxc-back
frontend pxc-onenode-front
bind *:3308
mode tcp
default_backend pxc-onenode-back
backend stats-back
mode http
balance roundrobin
stats uri /haproxy/stats
stats auth admin:admin
backend pxc-back
mode tcp
balance leastconn
option httpchk
server taotao 192.168.79.3:3306 check port 9200 inter 12000 rise 3 fall 3
server candidate 192.168.79.4:3306 check port 9200 inter 12000 rise 3 fall 3
server slave 192.168.79.5:3306 check port 9200 inter 12000 rise 3 fall 3
backend pxc-onenode-back
mode tcp
balance leastconn
option httpchk
server taotao 192.168.79.3:3306 check port 9200 inter 12000 rise 3 fall 3
server candidate 192.168.79.4:3306 check port 9200 inter 12000 rise 3 fall 3 backup
server slave 192.168.79.5:3306 check port 9200 inter 12000 rise 3 fall 3 backup
2）配置haproxy的日志：
安装完HAProxy后，默认情况下，HAProxy为了节省读写IO所消耗的性能，默认情况下没有日志输出，一下是开启日志的过程
# rpm -qa |grep rsyslog
rsyslog-5.8.10-8.el6.x86_64
# rpm -ql rsyslog |grep conf$
# vim /etc/rsyslog.conf
...........
$ModLoad imudp
$UDPServerRun 514 //rsyslog 默认情况下，需要在514端口监听UDP，所以可以把这两行注释掉
.........
local0.* /var/log/haproxy.log //和haproxy的配置文件中定义的log level一致
# service rsyslog restart
Shutting down system logger: [ OK ]
Starting system logger: [ OK ]
# service rsyslog status
rsyslogd (pid 11437) is running...
3、在每个PXC 每个mysql节点安装mysql健康状态检查脚本(需要在pxc的每个节点执行)
1）脚本拷贝
# cp /usr/local/mysql/bin/clustercheck /usr/bin/
# cp /usr/local/mysql/xinetd.d/mysqlchk /etc/xinetd.d/
ps：clustercheck和脚本都是默认值没有修改
2）创建mysql用户，用于mysql健康检查（在任一节点即可）：
> grant process on *.* to 'clustercheckuser'@'localhost' identified by 'clustercheckpassword!';
> flush privileges;
ps：如不使用clustercheck中默认用户名和密码，将需要修改clustercheck脚本，MYSQL_USERNAME和MYSQL_PASSWORD值
3）更改/etc/services添加mysqlchk的服务端口号：
# echo 'mysqlchk 9200/tcp # mysqlchk' >> /etc/services
4）安装xinetd服务，通过守护进程来管理mysql健康状态检查脚本
# yum -y install xinetd
# /etc/init.d/xinetd restart
Stopping xinetd: [FAILED]
Starting xinetd: [ OK ]
# chkconfig --level 2345 xinetd on
# chkconfig --list |grep xinetd
xinetd 0:off 1:off 2:on 3:on 4:on 5:on 6:off
测试检测脚本：
# clustercheck
HTTP/1.1 200 OK
Content-Type: text/plain
Connection: close
Content-Length: 40
Percona XtraDB Cluster Node is synced.
# curl -I 192.168.79.5:9200
HTTP/1.1 503 Service Unavailable
Content-Type: text/plain
Connection: close
Content-Length: 57
# cp /usr/local/mysql/bin/mysql /usr/bin/
# curl -I 192.168.79.5:9200
HTTP/1.1 200 OK
Content-Type: text/plain
Connection: close
Content-Length: 40
ps：要保证状态为200，否则检测不通过，可能是mysql服务不正常，或者环境不对致使haproxy无法使用mysql
haproxy如何侦测 MySQL Server 是否存活，靠着就是 9200 port，透过 Http check 方式，让 HAProxy 知道 PXC 状态
在mysql集群的其他节点执行上面操作，保证各个节点返回状态为200，如下：
# curl -I 192.168.79.4:9200
HTTP/1.1 200 OK
Content-Type: text/plain
Connection: close
Content-Length: 40
# curl -I 192.168.79.5:9200
HTTP/1.1 200 OK
Content-Type: text/plain
Connection: close
Content-Length: 40
4、HAproxy启动和关闭
在haproxy服务器上启动haproxy服务:
# /usr/local/sbin/haproxy -f /etc/haproxy/haproxy.cfg
关闭：
#pkill haproxy
# /usr/local/sbin/haproxy -f /etc/haproxy/haproxy.cfg
# ps -ef |grep haproxy
nobody 5751 1 0 21:18 ? 00:00:00 /usr/local/sbin/haproxy -f /etc/haproxy/haproxy.cfg
root 5754 2458 0 21:19 pts/0 00:00:00 grep haproxy
]# netstat -nlap |grep haproxy
tcp 0 0 0.0.0.0:8088 0.0.0.0:* LISTEN 5751/haproxy
tcp 0 0 0.0.0.0:3307 0.0.0.0:* LISTEN 5751/haproxy
tcp 0 0 0.0.0.0:3308 0.0.0.0:* LISTEN 5751/haproxy
udp 0 0 0.0.0.0:45891 0.0.0.0:* 5751/haproxy
# cp /usr/local/sbin/haproxy /usr/sbin/haproxy
cd /opt/soft/haproxy-1.5.3/examples
[root@db169 examples]# cp haproxy.init /etc/init.d/haproxy
[root@db169 examples]# chmod +x /etc/init.d/haproxy
5、haproxy测试
在mysql pxc创建测试账号：
#grant all privileges on *.* to 'taotao'@’%’ identified by ‘taotao’;
#for i in `seq 1 1000`; do mysql -h 192.168.79.128 -P3307 -utaotao -ptaotao -e "select @@hostname;"; done
#for i in `seq 1 1000`; do mysql -h 192.168.79.128 -P3308 -utaotao -ptaotao -e "select @@hostname;"; done
注：其实可以只允许haproxy侧的IP访问即可，因用户通过vip访问mysql集群，haproxy根据调度策略使用自己的ip创建与后端mysql服务器的连接。
查看Haproxy状态：
http://192.168.79.128:8088/haproxy/stats
输入用户密码：stats auth admin admin
三、用keepalived实现haproxy 的高可用
接着在192.168.79.128 和192.168.79.5节点，安装配置keepalived，防止是HAPROXY单点故障对数据库的访问产生影响，给服务器之间通过KEEPALIVED进行心跳检测，如果其中的某个机器出现问题，其中的一台将会接管，对用户来说整个过程透明
在192.168.79.128和192.168.79.5上安装配置：
# yum install keepalived -y
#yum install MySQL-python -y
# mv /etc/keepalived/keepalived.conf /etc/keepalived/keepalived.conf.bak
# vim /etc/keepalived/keepalived.conf
! Configuration File for keepalived
global_defs {
router_id haproxy_ha #keepalived组的名称
}
vrrp_script chk_haprocy {
script "/etc/keepalived/check_haproxy.sh"
interval 2
weight 2
}
vrrp_instance VI_HAPROXY {
state MASTER #备份机是BACKUP
#nopreempt #非抢占模式
interface eth0
virtual_router_id 51 #同一集群中该数值要相同,只能从1-255
priority 100 //备库可以90
advert_int 1
authentication {
auth_type PASS #Auth 用密码，但密码不要超过8位
auth_pass 1111
}
track_script {
chk_haprocy
}
virtual_ipaddress {
192.168.79.166/24
}
}
这里state不配置MASTER，是期望在MASTER宕机后再恢复时，不主动将MASTER状态抢过来，避免MySQL服务的波动。
由于不存在使用lvs进行负载均衡，不需要配置虚拟服务器virtual server，下同。
#vim /etc/keepalived/check_haproxy.sh
#!/bin/bash
A=`ps -C haproxy --no-header |wc -l`
if [ $A -eq 0 ];then
/usr/local/sbin/haproxy -f /etc/haproxy/haproxy.cfg
sleep 3
if [ `ps -C haproxy --no-header |wc -l` -eq 0 ];then
/etc/init.d/keepalived stop
fi
fi
#chmod 755 /etc/keepalived/check_haproxy.sh
启用keepalived
#service keepalived start
# chkconfig --level 2345 keepalived on
# tail -f /var/log/messages //keepalived的日志
ps：先启动，你内心期望成为对外服务的机器，确认VIP绑定到那台机器上， keepalived进入到master状态持有vip
keepalived 三种状态 1)backup 2)master 3)尝试进入master状态，没成功: FAULT
haproxy高可用测试：
check_haproxy.sh脚本可知，测试如果是只关闭haproxy服务，还是会自动重新，如果haproxy服务重启成功，是不会关闭keepalived的，
vip也不会飘到haproxy备机上，所以给测试需要关闭keepalived或关闭服务器才能达到效果。当master的挂掉后，处于backup的keepalived可以自动接管，
当master启动后vip会自动偏移过来。
在其中某台机子上关闭keepalived服务,/etc/init.d/keepalived stop,在经过1s的心跳检测后，会自动切换到另一台机子上，可以通过/var/log/messages进行查看
192.168.79.128：
# ip a
2: eth0:
link/ether 00:0c:29:7c:e0:ce brd ff:ff:ff:ff:ff:ff
inet 192.168.79.128/24 brd 192.168.79.255 scope global eth0
inet 192.168.79.166/32 scope global eth0
192.168.79.5:
# ip a
2: eth0:
link/ether 00:0c:29:d2:83:87 brd ff:ff:ff:ff:ff:ff
inet 192.168.79.5/24 brd 192.168.79.255 scope global eth0
192.168.79.128：
# /etc/init.d/keepalived stop
Stopping keepalived: [ OK ]
[root@taotao ~]# ip a
2: eth0:
link/ether 00:0c:29:7c:e0:ce brd ff:ff:ff:ff:ff:ff
inet 192.168.79.128/24 brd 192.168.79.255 scope global eth0
inet6 fe80::20c:29ff:fe7c:e0ce/64 scope link
valid_lft forever preferred_lft forever
192.168.79.5:
# ip a
2: eth0:
link/ether 00:0c:29:d2:83:87 brd ff:ff:ff:ff:ff:ff
inet 192.168.79.5/24 brd 192.168.79.255 scope global eth0
inet 192.168.79.166/32 scope global eth0
inet6 fe80::20c:29ff:fed2:8387/64 scope link
valid_lft forever preferred_lft forever
192.168.79.128：
# /etc/init.d/keepalived start
Starting keepalived: [ OK ]
# ip a
2: eth0:
link/ether 00:0c:29:7c:e0:ce brd ff:ff:ff:ff:ff:ff
inet 192.168.79.128/24 brd 192.168.79.255 scope global eth0
inet 192.168.79.166/32 scope global eth0
# ip a
2: eth0:
link/ether 00:0c:29:d2:83:87 brd ff:ff:ff:ff:ff:ff
inet 192.168.79.5/24 brd 192.168.79.255 scope global eth0