HaProxy+Keepalived+Mycat高可用集群配置
部署图：
集群部署图理解：
1、keepalived和haproxy必须装在同一台机器上（如192.168.46.161机器上，keepalived和haproxy都要安装），keepalived负责为该服务器抢占vip（虚拟ip），抢占到vip后，对该主机的访问可以通过原来的ip（192.168.46.161）访问，也可以直接通过vip（192.168.46.180）访问。
2、192.168.46.162上的keepalived也会去抢占vip，抢占vip时有优先级，配置keepalived.conf中的（priority 150 #数值愈大，优先级越高,192.168.46.162上改为120，master和slave上该值配置不同）决定。但是一般哪台主机上的keepalived服务先启动就会抢占到vip，即使是slave，只要先启动也能抢到。
3、haproxy负责将对vip的请求分发到mycat上。起到负载均衡的作用，同时haproxy也能检测到mycat是否存活，haproxy只会将请求转发到存活的mycat上。
4、如果一台服务器（keepalived+haproxy服务器）宕机，另外一台上的keepalived会立刻抢占vip并接管服务。如果一台mycat服务器宕机，haporxy转发时不会转发到宕机的mycat上，所以mycat依然可用。
1、Haproxy的安装
1.1、配置haprxoy
（下载地址: http://www.haproxy.org/#down）
useradd haproxy
cd haproxy-1.4.27/
make TARGET=linux26 PREFIX=/usr/local/haproxy ARCH=x86_64
make install PREFIX=/usr/local/haproxy
cd /usr/local/haproxy
vi haproxy.cfg
增加如下内容：
global
log 127.0.0.1 local0
maxconn 4096
chroot /usr/local/haproxy
user haproxy
group haproxy
daemon
defaults
log global
option dontlognull
retries 3
option redispatch
maxconn 2000
contimeout 5000
clitimeout 50000
srvtimeout 50000
listen admin_stats 192.168.46.180:48800
stats uri /admin-status
stats auth admin:admin
mode http
option httplog
listen mycat_service 192.168.46.180:18066
mode tcp
option tcplog
option httpchk OPTIONS * HTTP/1.1 Host: www
balance roundrobin
server mycat_161 192.168.46.161:8066 check port 48700 inter 5s rise 2 fall 3
server mycat_162 192.168.46.162:8066 check port 48700 inter 5s rise 2 fall 3
srvtimeout 20000
listen mycat_admin 192.168.46.180:19066
mode tcp
option tcplog
option httpchk OPTIONS * HTTP/1.1 Host: www
balance roundrobin
server mycat_161 192.168.46.161:9066 check port 48700 inter 5s rise 2 fall 3
server mycat_162 192.168.46.162:9066 check port 48700 inter 5s rise 2 fall 3
srvtimeout 20000
1.2、配置haproxy记录日志功能
yum install rsyslog -y
cd /etc/rsyslog.d/
vi haproxy.conf
增加内容：
$ModLoad imudp
$UDPServerRun 514
local0.* /var/log/haproxy.log
vi /etc/rsyslog.conf
在#### RULES ####上面一行加入以下内容
# Include all config files in /etc/rsyslog.d/
$IncludeConfig /etc/rsyslog.d/*.conf
在local7.* /var/log/boot.log下面加入以下内容
local0.* /var/log/haproxy.log
重启rsyslog服务并将rsyslog加入自动启动服务
service rsyslog restart
chkconfig --add rsyslog
chkconfig --level 2345 rsyslog on
1.3 配置监听mycat是否存活(在Mycat server1 Mycat server2上都需要添加检测端口48700的脚本，为此需要用到xinetd，xinetd为linux系统的基础服务)
yum install xinetd -y
cd /etc/xinetd.d
vi mycat_status
增加内容：
service mycat_status
{
flags = REUSE
socket_type = stream
port = 48700
wait = no
user = nobody
server = /usr/local/bin/mycat_status
log_on_failure += USERID
disable = no
}
vi /usr/local/bin/mycat_status (创建xinetd启动服务脚本)
增加内容：
#!/bin/bash
#/usr/local/bin/mycat_status.sh
# This script checks if a mycat server is healthy running on localhost. It will
# return:
#
# "HTTP/1.x 200 OK " (if mycat is running smoothly)
#
# "HTTP/1.x 503 Internal Server Error " (else)
mycat=`/usr/local/mycat/bin/mycat status |grep 'not running'| wc -l`
if [ "$mycat" = "0" ];
then
/bin/echo -e "HTTP/1.1 200 OK "
else
/bin/echo -e "HTTP/1.1 503 Service Unavailable "
fi
修改脚本文件权限
chmod 777 /usr/local/bin/mycat_status
chmod 777 /etc/xinetd.d/mycat_status
将启动脚本加入服务
vi /etc/services
末尾增加：
mycat_status 48700/tcp # mycat_status
重启xinetd服务并将xinetd加入自启动服务
service xinetd restart
chkconfig --add xinetd
chkconfig --level 2345 xinetd on
验证mycat_status服务是否启动成功
netstat -antup|grep 48700
1.4、创建haproxy启停脚本
1.4.1、启动脚本
vi /usr/local/haproxy/sbin/start
增加内容：
#!/bin/sh
/usr/local/haproxy/sbin/haproxy -f /usr/local/haproxy/haproxy.cfg &
增加权限：
chmod +x /usr/local/haproxy/sbin/start
1.4.2、关闭脚本
vi /usr/local/haproxy/sbin/stop
增加内容：
#!/bin/sh
ps -ef | grep sbin/haproxy | grep -v grep |awk '{print $2}'|xargs kill -s 9
增加权限：
chmod +x /usr/local/haproxy/sbin/stop
1.4.3、授权
chown -R haproxy.haproxy /usr/local/haproxy/*
1.5、启动haproxy
启动haproxy前必须先启动keepalived，否则启动不了。
启动命令：
/usr/local/haproxy/sbin/haproxy -f /usr/local/haproxy/haproxy.cfg
启动haproxy异常情况
如果报以下错误：
[root@localhost bin]# /usr/local/haproxy/sbin/haproxy -f /usr/local/haproxy/haproxy.cfg
[ALERT] 183/115915 (12890) :Starting proxy admin_status: cannot bind socket
[ALERT] 183/115915 (12890) :Starting proxy allmycat_service: cannot bind socket
[ALERT] 183/115915 (12890) :Starting proxy allmycat_admin: cannot bind socket
原因为：该机器没有抢占到vip，如果另一台服务启动正常，这个错误可以忽略不管，如果另一台也一样，使用ping vip命令看看vip是否生效，如果没有生效，说明keepalived没有启动成功，回去检查keepalived的异常再说。启动后可以通过http://192.168.46.180:48800/admin-status (用户名密码都是admin，haproxy.cfg中配置的)
2、Keepalived安装
2.1 openssl安装
(下载地址：https://www.openssl.org/source/)
openssl必须安装，否则安装keepalived时无法编译，keepalived依赖openssl
tar -zxvf openssl-1.0.2l.tar.gz
cd openssl-1.0.2l
./config --prefix=/usr/local/openssl
./config -t
make depend
make
make test
make install
ln -s /usr/local/openssl /usr/local/ssl
vi /etc/ld.so.conf
在文件末尾加入以下内容
/usr/local/openssl/lib
修改环境变量
vi /etc/profile
在文件末尾加入以下内容
export OPENSSL=/usr/local/openssl/bin
export PATH=$PATH:$OPENSSL
source /etc/profile
安装openssl-devel
yum install openssl-devel -y
测试
ldd /usr/local/openssl/bin/openssl
linux-vdso.so.1 => (0x00007fff996b9000)
libdl.so.2 =>/lib64/libdl.so.2 (0x00000030efc00000)
libc.so.6 =>/lib64/libc.so.6 (0x00000030f0000000)
/lib64/ld-linux-x86-64.so.2 (0x00000030ef800000)
which openssl
/usr/bin/openssl
openssl version
OpenSSL 1.0.0-fips 29 Mar 2010
2.2 keepalived安装
在192.168.46.161，192.168.46.162两台机器进行keepalived安装
tar zxvf keepalived-1.2.13.tar.gz
cd keepalived-1.2.13
./configure --prefix=/usr/local/keepalived
make
make install
cp /usr/local/keepalived/sbin/keepalived /usr/sbin/
cp /usr/local/keepalived/etc/sysconfig/keepalived /etc/sysconfig/
cp /usr/local/keepalived/etc/rc.d/init.d/keepalived /etc/init.d/
mkdir /etc/keepalived
cd /etc/keepalived/
cp /usr/local/keepalived/etc/keepalived/keepalived.conf /etc/keepalived
mkdir -p /usr/local/keepalived/var/log
keepalived配置
建检查haproxy是否存活的脚本
mkdir /etc/keepalived/scripts
cd /etc/keepalived/scripts
vi /etc/keepalived/keepalived.conf
Master的配置：
! Configuration File for keepalived
vrrp_script chk_http_port {
script"/etc/keepalived/scripts/check_haproxy.sh"
interval 2
weight 2
}
vrrp_instance VI_1 {
state MASTER
interface eth1
virtual_router_id 51
priority 150
advert_int 1
authentication
auth_type PASS
auth_pass 1111
}
track_script {
chk_http_port
}
virtual_ipaddress {
192.168.46.180 dev eth1 scope global
}
notify_master /etc/keepalived/scripts/haproxy_master.sh
notify_backup /etc/keepalived/scripts/haproxy_backup.sh
notify_fault /etc/keepalived/scripts/haproxy_fault.sh
notify_stop /etc/keepalived/scripts/haproxy_stop.sh
}
Slave的配置：
! Configuration File for keepalived
vrrp_script chk_http_port {
script"/etc/keepalived/scripts/check_haproxy.sh"
interval 2
weight 2
}
vrrp_instance VI_1 {
state BACKUP
interface eth1
virtual_router_id 51
priority 150
advert_int 1
authentication
auth_type PASS
auth_pass 1111
}
track_script {
chk_http_port
}
virtual_ipaddress {
192.168.46.180 dev eth1 scope global
}
notify_master /etc/keepalived/scripts/haproxy_master.sh
notify_backup /etc/keepalived/scripts/haproxy_backup.sh
notify_fault /etc/keepalived/scripts/haproxy_fault.sh
notify_stop /etc/keepalived/scripts/haproxy_stop.sh
}
1. virtual_router_id 51 这个代表一个集群组，如果同一个网段还有另一组集群，请使用不同的组编号区分。如换成52、53等。
2. interface eth1 和172.17.210.103 dev eth1 scope global中的eth1指的是网卡，如果是多网卡，可能会有
eth0，eth1，eth2…，可以使用ifconfig命令查看，确保eth0是本机存在的网卡地址。有些服务器如果只有一个网卡，但被人为把eth0改成eth1了，你再写eth0就找不到了的。
vi /etc/keepalived/scripts/check_haproxy.sh
#!/bin/bash
STARTHAPROXY="/usr/local/haproxy/sbin/haproxy -f /usr/local/haproxy/haproxy.cfg"
STOPKEEPALIVED="/etc/init.d/keepalived stop"
LOGFILE="/usr/local/keepalived/var/log/keepalived-haproxy-state.log"
echo "[check_haproxy status]" >> $LOGFILE
A=`ps -C haproxy --no-header |wc -l`
echo "[check_haproxy status]" >> $LOGFILE
date >> $LOGFILE
if [ $A -eq 0 ];then
echo $STARTHAPROXY >> $LOGFILE
$STARTHAPROXY >> $LOGFILE 2>&1
sleep 5
fi
if [ `ps -C haproxy --no-header |wc -l` -eq 0 ];then
exit 0
else
exit 1
fi
vi /etc/keepalived/scripts/haproxy_master.sh
#!/bin/bash
STARTHAPROXY=`/usr/local/haproxy/sbin/haproxy -f /usr/local/haproxy/haproxy.cfg`
STOPHAPROXY=`ps -ef | grep sbin/haproxy | grep -v grep | awk '{print $2}'| xargs kill -s 9`
LOGFILE="/usr/local/keepalived/var/log/keepalived-haproxy-state.log"
echo "[master]" >> $LOGFILE
date >> $LOGFILE
echo "Being master...." >> $LOGFILE 2>&1
echo "stop haproxy...." >> $LOGFILE 2>&1
$STOPHAPROXY >> $LOGFILE 2>&1
echo "start haproxy...." >> $LOGFILE 2>&1
$STARTHAPROXY >> $LOGFILE 2>&1
echo "haproxy stared ..." >> $LOGFILE
vi /etc/keepalived/scripts/haproxy_backup.sh
#!/bin/bash
STARTHAPROXY=`/usr/local/haproxy/sbin/haproxy -f /usr/local/haproxy/haproxy.cfg`
STOPHAPROXY=`ps -ef | grep sbin/haproxy | grep -v grep | awk '{print $2}'| xargs kill -s 9`
LOGFILE="/usr/local/keepalived/var/log/keepalived-haproxy-state.log"
echo "[backup]" >> $LOGFILE
date >> $LOGFILE
echo "Being backup...." >> $LOGFILE 2>&1
echo "stop haproxy...." >> $LOGFILE 2>&1
$STOPHAPROXY >> $LOGFILE 2>&1
echo "start haproxy...." >> $LOGFILE 2>&1
$STARTHAPROXY >> $LOGFILE 2>&1
echo "haproxy stared ..." >> $LOGFILE
vi /etc/keepalived/scripts/haproxy_fault.sh
#!/bin/bash
LOGFILE=/usr/local/keepalived/var/log/keepalived-haproxy-state.log
echo "[fault]" >> $LOGFILE
date >> $LOGFILE
vi /etc/keepalived/scripts/haproxy_stop.sh
#!/bin/bash
LOGFILE=/usr/local/keepalived/var/log/keepalived-haproxy-state.log
echo "[stop]" >> $LOGFILE
date >> $LOGFILE
赋予脚本可执行权限
chmod 777 /etc/keepalived/scripts/*
将keepalived加入自启动服务并启动
chkconfig --add keepalived
chkconfig --level 2345 keepalived on
service keepalived start
3、搭建完成
表明搭建完成！