0、本次集羣架構如下（先搭建好主從同步）：
集羣架構圖(如上）
1、分別在主、備庫上創建同步複製賬號：
create user 'bak'@'10.161.181.%' identified by 'root123';
grant replication slave on *.* to 'bak'@'10.161.181.%';
flush privileges;
2、先在備庫上10.161.181.224主機上配置同步信息：
mysql -uroot -proot123;
change master to master_host='10.161.181.223',master_user='bak',master_password='root123',master_auto_position=1;
start slave;
3、之後再在主庫上10.161.181.223上配置主從同步信息：
change master to master_host='10.161.181.224',master_user='bak',master_password='root123',master_auto_position=1;
start slave;
show slave status\G;
到此，雙主同步建立完成。
備註：
允許root用戶連接（授予下面權限）：mysql -h 10.161.181.223 -uroot -proot123 -P3306 -e "show status"
create user 'root'@'10.161.181.%' identified by 'root123';
grant select,insert,update,delete on root.* to 'root'@'10.161.181.%' identified by 'root123';
4、分別在兩臺主機上安裝keepalived軟件包:
https://keepalived.org/download.html （本次下載：keepalived-1.4.5.tar.gz）或yum源安裝：yum -y install keepalived;
源碼安裝：
4.1先安裝keepalived環境條件：
yum -y install curl gcc openssl-devel libnl3-devel net-snmp-devel
yum -y install libnl libnl-devel
yum install -y libnfnetlink-devel
4.2解壓安裝包:
tar -zxvf keepalived-1.4.5.tar.gz
cd keepalived-1.4.5
mkdir /usr/local/keepalived
chmod 775 /usr/local/keepalived/
./configure --prefix=/usr/local/keepalived
make && make install
make && make install如下：
4.3安裝完成，生成相應文檔：
cp /usr/local/keepalived/etc/sysconfig/keepalived /etc/sysconfig/keepalived #cp啓動腳本文檔到操作系統配置文件下：
cp /usr/local/keepalived/sbin/keepalived /usr/sbin/keepalived #添加keepalived啓動程序到系統環境命令：
cp /root/wlp/keepalived-1.4.5/keepalived/etc/init.d/keepalived /etc/init.d/keepalived #keepalived啓動腳本（源碼目錄下），放到/etc/init.d/目錄下就可以使用service命令便捷調用
mkdir /etc/keepalived ； #將配置文件放到默認路徑下
cp /usr/local/keepalived/etc/keepalived/keepalived.conf /etc/keepalived/keepalived.conf
添加系統服務併爲自啓動：
4.4在兩臺主機上配置檢測mysql數據庫的腳本 ：
cd /etc/keepalived
vi checkmysql.sh
#!/bin/bash
#author=wlp
mysqlstr=/usr/local/mysql/bin/mysql
host=10.161.181.223
user=admin
password=root123
port=3306
##mysql service ok=1 ,else = 0
mysql_status=1
###check mysql status#####
$mysqlstr -h $host -u $user -p$password -P$port -e "show status;" >/dev/null 2>&1
if [ $? = 0 ] ; then
echo "mysql_status=1"
exit 0
else
/etc/init.d/keepalived stop
fi
chmod 775 /etc/keepalived/checkmysql.sh或chmod +x /etc/keepalived/checkmysql.sh
4.5創建checkmysql.sh腳本檢查用戶：
創建admin管理用戶：
create user 'admin'@'10.161.181.%' identified by 'root123';
grant all privileges on *.* to 'admin'@'10.161.181.%';
GRANT ALL PRIVILEGES ON *.* TO 'admin'@'%' IDENTIFIED BY 'root123' WITH GRANT OPTION;
flush privileges;
4.6修改兩臺主機keepalived配置文件：
223主機1:
vi /etc/keepalived/keealived.conf
! Configuration File for keepalived
vrrp_script vs_mysql_223 {
script "/etc/keepalived/checkmysql.sh"
interval 10
}
vrrp_instance VI_223 {
state BACKUP
nopreempt
interface eth0
virtual_router_id 223
priority 223
advert_int 5
authentication {
auth_type PASS
auth_pass root123
}
track_script {
vs_mysql_223
}
virtual_ipaddress {
10.161.181.226
}
}
224主機2:
! Configuration File for keepalived
vrrp_script vs_mysql_224 {
script "/etc/keepalived/checkmysql.sh"
interval 10
}
vrrp_instance VI_224 {
state BACKUP
nopreempt
interface eth0
virtual_router_id 223
priority 90
advert_int 5
authentication {
auth_type PASS
auth_pass root123
}
track_script {
vs_mysql_224
}
virtual_ipaddress {
10.161.181.226
}
}
4.7啓動兩臺主機keepalived進程：
使用另外一臺mysql 225，測試 vip是否可以連接到主庫223：
show status\s確定連接爲vip：
到此雙主架構建立完成。
5.故障模擬切換：
在主庫上關閉mysql服務：/usr/local/mysql/bin/mysqladmin -uroot -proot123 shutdown
查看keepalived日誌情況：tail -f /var/log/messages(vip removed &&keepalived stop）
備庫上查看keepalived日誌：tail -f /var/log/messages (keepalived backup轉換爲master&& vip切換到備機上）
此上不影響用戶使用，轉換時會間斷：mysql -uadmin -proot123 -h10.161.181.226
show status \s;
在225上通過vip驗證：
再把223主機mysql服務開啓：service mysqld start;
檢查同步，都正常了：mysql -uroot -proot123 ; show slave status\G;
切換原主節點到223：啓動223上主機keepalived:/etc/init.d/keepalived start;
關閉224上mysql：mysqladmin -uroot -proot123 shutdown;
檢查vip和mysql同步：已經切換到223節點並且服務正在連接：
開啓224上mysql並檢查主從同步:service mysqld restart
VIP測試連接正常：