为解决Mysql数据库单点问题，实现两台MySQL数据库互为主备，双向replication。当一Master出现问题，则将Slave切换为Master继续工作.
环境说明
系统版本：CentOS Linux release 7.6.1810 (Core)
MySQL版本：mysql Ver 14.14 Distrib 5.7.27
keepalived版本：Keepalived v1.2.13
序号 服务器IP 用途
1 192.168.158.10 Master
2 192.168.158.20 Slave
3 192.168.158.30 VIP
一、MySQL互为主从配置
1.> 两台安装相同版本的MySQL数据库.
2.> 主备机NTP时钟同步
3.> 双机互信配置ssh免密认证
4.> 数据库配置(Master的配置和Slave的配置server-id不能一致,别的都可以一样)
4.1> 修改Master主机上MySQL数据库的配置文件，然后新启动MySQL
#vim /ect/my.cnf [mysqld] log-bin=mysql-bin server-id=100 expire_logs_days = 10 datadir=/var/lib/mysql socket=/var/lib/mysql/mysql.sock symbolic-links=0 log-error=/var/log/mysqld.log pid-file=/var/run/mysqld/mysqld.pid validate_password=off #关闭密码安全策略 default_password_lifetime=0 #设置密码不过期 log_bin=/var/log/mysql/mysql-bin
4.2> 修改Slave主机上MySQL数据库的配置文件，然后新启动MySQL
#vim /ect/my.cnf [mysqld] log-bin=mysql-bin server-id=101 expire_logs_days = 10 datadir=/var/lib/mysql socket=/var/lib/mysql/mysql.sock symbolic-links=0 log-error=/var/log/mysqld.log pid-file=/var/run/mysqld/mysqld.pid validate_password=off default_password_lifetime=0 log_bin=/var/log/mysql/mysql-bin
5.> 启动MySQL服务
# systemctl start mysqld
6.> 查询相关状态，以Master主机为例，如下
mysql> show master status; +------------------+----------+--------------+------------------+-------------------+ | File | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set | +------------------+----------+--------------+------------------+-------------------+ | mysql-bin.000001 | 154 | | | | +------------------+----------+--------------+------------------+-------------------+ 1 row in set (0.00 sec)
7.> 创建复制账号并同步
7.1> 在Master库和Slave库分别执行，创建数据同步复制账号.
mysql> GRANT REPLICATION SLAVE,REPLICATION CLIENT ON *.* TO replication@'%' IDENTIFIED BY 'replication'; mysql> flush privileges;
7.2> 7.2> 在Master主机上,执行同步操作(注意master_host参数主备机相互指向),如下：
mysql> change master to master_host='192.168.158.20',master_port=3306,master_user='replication',master_password='replication',master_log_file='mysql-bin.000001',master_log_pos=154; mysql> start slave;
7.3> 在Slave主机上,执行同步操作(注意master_host参数主备机相互指向),如下：
mysql> change master to master_host='192.168.158.10',master_port=3306,master_user='replication',master_password='replication',master_log_file='mysql-bin.000001',master_log_pos=154; mysql> start slave;
7.4> 在Master、Slave主机上，查询同步状态“show slave statusG”，检查结果中Slave_IO_Running: Yes和Slave_SQL_Running: Yes，否则有异常。
8.> 配置密文命令访问(两台主机都配置)
Mysql数据库使用mysql或mysqldump等相关命令时，需要在命令行界面输入密码，当使用脚本时，在脚本里填写密码显然不太安全，因此可以设置Mysql的密文文件。
# mysql_config_editor set --login-path=local --user=root --port=3306 --password # mysql_config_editor print --all
9.> 创建切换脚本
切换脚本规划，如本次是mysql切换，因此在该目录下创建mysql目录,将所有切换脚本放在/home/mysql目录下,本次相关脚本说明如下：
进入/home/mysql目录，如下文件：
Logs //存储日志的文件目录
mybackup.sh //清空slave配置，重新获取远程日志文件及Pos,并开启同步
mycheck.sh //检查mysql运行状态，如果运行正常，退出。如果运行不正常调用pkill keepalived
mymaster.sh //先判断同步复制是否执行完成，如果未执行完成等待1分钟后，停止同步（stop slave;），并且记录切换后的日志和pos
.mysqlenv //脚本运行环境文件
mystop.sh //设置参数保证数据不丢失，最后检查看是否还有写操作，最后1分钟退出
syncposfile //每次切换后，Master最后一次File值和Position值。
10.环境文件
10.1> Master主机端的环境文件
[root@localhost mysql]# vim .mysqlenv MYSQL=/usr/bin/mysql MYSQL_CMD="--login-path=local" #远端主机的IP地址 REMOTE_IP=192.168.158.20 export mysql="$MYSQL $MYSQL_CMD "
10.2> Slave主机端的环境文件
[root@localhost mysql]# vim .mysqlenv MYSQL=/usr/bin/mysql MYSQL_CMD="--login-path=local" #远端主机的IP地址 REMOTE_IP=192.168.158.10 export mysql="$MYSQL $MYSQL_CMD"
11.> 服务检查脚本
11.1> mycheck.sh
[root@localhost mysql]# vim mycheck.sh #!/bin/sh ################################################## #File Name : mycheck.sh #Description: mysql is working MYSQL_OK is 1 # mysql is down MYSQL_OK is 0 ################################################## BASEPATH=/home/mysql LOGSPATH=$BASEPATH/logs source $BASEPATH/.mysqlenv CHECK_TIME=3 MYSQL_OK=1 ################################################################## function check_mysql_helth (){ $mysql -e "show status;" >/dev/null 2>&1 if [ $? == 0 ] then MYSQL_OK=1 else MYSQL_OK=0 #systemctl status keepalived fi return $MYSQL_OK } #check_mysql_helth while [ $CHECK_TIME -ne 0 ] #不等于 do let "CHECK_TIME -= 1" check_mysql_helth if [ $MYSQL_OK = 1 ] ; then CHECK_TIME=0 echo "$(date "+%Y-%m-%d %H:%M:%S") The scripts mycheck.sh is running ..." >> $LOGSPATH/mysql_switch.log exit 0 fi if [ $MYSQL_OK -eq 0 ] && [ $CHECK_TIME -eq 0 ] #等于 then systemctl stop keepalived echo "$(date "+%Y-%m-%d %H:%M:%S") The mycheck.sh, mysql is down, after switch..." >> $LOGSPATH/mysql_switch.log exit 1 fi sleep 1 done [root@localhost mysql]#
11.2> 切换脚本
[root@localhost mysql]# vim mymaster.sh #!/bin/sh ################################################## #File Name : mymaster.sh #Description: First determine whether synchronous # replication is performed, and if no # execution is completed, wait for 1 # minutes. Log logs and POS after # switching, and record files synchronously. ################################################## BASEPATH=/home/mysql LOGSPATH=$BASEPATH/logs source $BASEPATH/.mysqlenv $mysql -e "show slave statusG" > $LOGSPATH/mysqlslave.states Master_Log_File=`cat $LOGSPATH/mysqlslave.states | grep -w Master_Log_File | awk -F": " '{print $2}'` Relay_Master_Log_File=`cat $LOGSPATH/mysqlslave.states | grep -w Relay_Master_Log_File | awk -F": " '{print $2}'` Read_Master_Log_Pos=`cat $LOGSPATH/mysqlslave.states | grep -w Read_Master_Log_Pos | awk -F": " '{print $2}'` Exec_Master_Log_Pos=`cat $LOGSPATH/mysqlslave.states | grep -w Exec_Master_Log_Pos | awk -F": " '{print $2}'` i=1 while true do if [ $Master_Log_File = $Relay_Master_Log_File ] && [ $Read_Master_Log_Pos -eq $Exec_Master_Log_Pos ];then echo "$(date "+%Y-%m-%d %H:%M:%S") The mymaster.sh, slave sync ok... " >> $LOGSPATH/mysql_switch.log break else sleep 1 if [ $i -gt 60 ];then break fi continue let i++ fi done $mysql -e "stop slave;" $mysql -e "set global innodb_support_xa=0;" $mysql -e "set global sync_binlog=0;" $mysql -e "set global innodb_flush_log_at_trx_commit=0;" $mysql -e "flush logs;GRANT ALL PRIVILEGES ON *.* TO 'replication'@'%' IDENTIFIED BY 'replication';flush privileges;" $mysql -e "show master status;" > $LOGSPATH/master_status_$(date "+%y%m%d-%H%M").txt # sync pos file /usr/bin/scp $LOGSPATH/master_status_$(date "+%y%m%d-%H%M").txt root@$REMOTE_IP:$BASEPATH/syncposfile/backup_master.status echo "$(date "+%Y-%m-%d %H:%M:%S") The mymaster.sh, Sync pos file sucess." >> $LOGSPATH/mysql_switch.log [root@localhost mysql]#
11.3> 回切脚本
[root@localhost mysql]# vim mybackup.sh #!/bin/sh ################################################## #File Name : mybackup.sh #Description: Empty the slave configuration, retrieve # the remote log file and Pos, and open # the synchronization ################################################## BASEPATH=/home/mysql LOGSPATH=$BASEPATH/logs source $BASEPATH/.mysqlenv $mysql -e "GRANT ALL PRIVILEGES ON *.* TO 'replication'@'%' IDENTIFIED BY 'replication';flush privileges;" $mysql -e "set global innodb_support_xa=0;" $mysql -e "set global sync_binlog=0;" $mysql -e "set global innodb_flush_log_at_trx_commit=0;" $mysql -e "flush logs;" $mysql -e "reset slave all;" if [ -f $BASEPATH/syncposfile/backup_master.status ];then New_ReM_File=`cat $BASEPATH/syncposfile/backup_master.status | grep -v File |awk '{print $1}'` New_ReM_Position=`cat $BASEPATH/syncposfile/backup_master.status | grep -v File |awk '{print $2}'` echo "$(date "+%Y-%m-%d %H:%M:%S") This mybackup.sh, New_ReM_File:$New_ReM_File,New_ReM_Position:$New_ReM_Position" >> $LOGSPATH/mysql_switch.log $mysql -e "change master to master_host='$REMOTE_IP',master_port=3306,master_user='replication',master_password='replication',master_log_file='$New_ReM_File',master_log_pos=$New_ReM_Position;" $mysql -e "start slave;" $mysql -e "show slave statusG;" > $LOGSPATH/slave_status_$(date "+%y%m%d-%H%M").txt cat $LOGSPATH/slave_status_$(date "+%y%m%d-%H%M").txt >> $LOGSPATH/mysql_switch.log rm -f $BASEPATH/syncposfile/backup_master.status else echo "$(date "+%Y-%m-%d %H:%M:%S") The scripts mybackup.sh running error..." >> $LOGSPATH/mysql_switch.log fi [root@localhost mysql]#
11.4> 停止脚本
[root@localhost mysql]# vim mystop.sh #!/bin/sh ################################################## #File Name : mystop.sh #Description: Set parameters to ensure that the data # is not lost, and finally check to see # if there are still write operations, # the last 1 minutes to exit ################################################## BASEPATH=/home/mysql LOGSPATH=$BASEPATH/logs source $BASEPATH/.mysqlenv $mysql -e "GRANT ALL PRIVILEGES ON *.* TO 'replication'@'%' IDENTIFIED BY 'replication';flush privileges;" $mysql -e "set global innodb_support_xa=1;" $mysql -e "set global sync_binlog=1;" $mysql -e "set global innodb_flush_log_at_trx_commit=1;" $mysql -e "show master statusG" > $LOGSPATH/mysqlmaster0.states M_File1=`cat $LOGSPATH/mysqlmaster0.states | awk -F': ' '/File/{print $2}'` M_Position1=`cat $LOGSPATH/mysqlmaster0.states | awk -F': ' '/Position/{print $2}'` sleep 2 $mysql -e "show master statusG" > $LOGSPATH/mysqlmaster1.states M_File2=`cat $LOGSPATH/mysqlmaster1.states | awk -F': ' '/File/{print $2}'` M_Position2=`cat $LOGSPATH/mysqlmaster1.states | awk -F': ' '/Position/{print $2}'` i=1 while true do if [ $M_File1 = $M_File2 ] && [ $M_Position1 -eq $M_Position2 ];then echo "$(date "+%Y-%m-%d %H:%M:%S") The mystop.sh, master sync ok.." >> $LOGSPATH/mysql_switch.log exit 0 else sleep 1 if [$i -gt 60 ];then break fi continue let i++ fi done echo "$(date "+%Y-%m-%d %H:%M:%S") The mystop.sh, master sync exceed one minutes..." >> $LOGSPATH/mysql_switch.log [root@localhost mysql]#
二、Keepalived安装与配置
1.两台都安装Keepalived(略)
2.切换原理
Keepalived可实现将虚拟IP地址在实体物理机上来回漂移。Keepalived在转换状态时会依照状态来呼叫配置文件中内置的定义。
当进入Master状态时会呼叫notify_master定义的脚本
当进入Backup状态时会呼叫notify_backup定义的脚本
当keepalived程序终止时呼叫notify_stop定义的脚本
当发现异常情况时进入Fault状态呼叫notify_fault定义的脚本
切换的过程如下：
1.>在Master主机上keepalived运行时执行mycheck.sh脚本不停的检查mysql的运行状态，当发现mysql停止后将keepalived进程杀掉。
2.>此时Slave主机上会接管虚拟IP地址，并调用notify_master定义的脚本
3.>当原Master主机上的mysql和keepalived进程恢复正常后，会调用notify_backup定义的脚本，此时数据库的主端还在Savle主机上。
4.>回切，关闭Slave端的keepavlied进程，会调用notify_stop脚本，同时Master主机上会调用notify_master定义的脚本。此时数据库的主端在Master主机上
5.>启动Slave端的keepavlied进程，会调用notify_backup脚本，此时完成数据同步。
3.Keepalived的配置
在Master端和Savle端均安装好keepalived后，进行配置，修改/etc/keepalived/keepalived.conf文件.
3.1> Master端配置
[root@localhost keepalived]# cat keepalived.conf global_defs { router_id MySQL-HA } vrrp_script check_run { script "/home/mysql/mycheck.sh" interval 10 } vrrp_sync_group VG1 { group { VI_1 } } vrrp_instance VI_1 { state MASTER #state BACKUP interface enp0s3 virtual_router_id 51 priority 100 advert_int 1 #nopreempt authentication { auth_type PASS auth_pass 1234 } track_script { check_run } notify_master /home/mysql/mymaster.sh notify_backup /home/mysql/mybackup.sh notify_stop /home/mysql/mystop.sh virtual_ipaddress { 192.168.158.30/24 } }
3.2> Slave端配置
[root@localhost keepalived]# cat keepalived.conf global_defs { router_id MySQL-HA } vrrp_script check_run { script "/home/mysql/mycheck.sh" interval 10 } vrrp_sync_group VG1 { group { VI_1 } } vrrp_instance VI_1 { state MASTER #state BACKUP interface enp0s3 virtual_router_id 51 priority 90 advert_int 1 #nopreempt authentication { auth_type PASS auth_pass 1234 } track_script { check_run } notify_master /home/mysql/mymaster.sh notify_backup /home/mysql/mybackup.sh notify_stop /home/mysql/mystop.sh virtual_ipaddress { 192.168.158.30/24 } } [root@localhost keepalived]#
3.3> 重新启动相关服务
# systemctl restart keepalived
三、切换验证
1. 保证两台主机上面keepalived、MySQL服务都是正常启动着的.
2. 停止主端
2.1> 将MySQL进程杀死
[root@localhost ~]# systemctl stop mysqld
2.2> 检查状态
主端查看脚本切换日志
[root@localhost ~]# tail -100f /home/mysql/logs/mysql_switch.log ...... 2019-08-27 23:34:34 The scripts mycheck.sh is running ... 2019-08-27 23:34:44 The scripts mycheck.sh is running ... 2019-08-27 23:34:54 The scripts mycheck.sh is running ... 2019-08-27 23:35:04 The scripts mycheck.sh is running ... 2019-08-27 23:35:14 The scripts mycheck.sh is running ... 2019-08-27 23:35:25 The mycheck.sh, mysql is down, after switch...
2.3> 主端查看浮动IP地址的切换过程。
#浮动IP地址原先在Master端，如下：
# 切换后，在从Master端验查看，浮动IP已被切走到备机
# 在Slave端查看验证，确认
# 外部ping浮动IP地址效果，有一个丢包
2.4> 主端Keepalived日志/var/log/messages如下：
Aug 27 23:35:16 localhost systemd: Stopping MySQL Server... Aug 27 23:35:19 localhost systemd: Stopped MySQL Server. Aug 27 23:35:24 localhost systemd: Stopping SYSV: Start and stop Keepalived... Aug 27 23:35:24 localhost Keepalived[10554]: Stopping Keepalived v1.2.13 (08/17,2019) Aug 27 23:35:24 localhost Keepalived_vrrp[10557]: VRRP_Instance(VI_1) sending 0 priority Aug 27 23:35:24 localhost Keepalived_vrrp[10557]: VRRP_Instance(VI_1) removing protocol VIPs. Aug 27 23:35:24 localhost Keepalived_healthcheckers[10556]: Netlink reflector reports IP 192.168.158.30 removed Aug 27 23:35:24 localhost keepalived: Stopping keepalived: [ OK ] Aug 27 23:35:24 localhost systemd: Stopped SYSV: Start and stop Keepalived. Aug 27 23:35:29 localhost systemd: Started Session 23 of user root. Aug 27 23:35:29 localhost systemd-logind: New session 23 of user root. Aug 27 23:35:29 localhost systemd-logind: Removed session 23.
2.5> 备端查看切换日志/home/mysql/logs/mysql_switch.log
2019-08-27 23:35:29 The scripts mycheck.sh is running ... 2019-08-27 23:35:30 The mymaster.sh, slave sync ok... 2019-08-27 23:35:32 The mymaster.sh, Sync pos file sucess. 2019-08-27 23:35:39 The scripts mycheck.sh is running ...
2.6> 备端查看/var/log/messages.log日志
Aug 27 23:35:28 localhost Keepalived_vrrp[23052]: VRRP_Instance(VI_1) Transition to MASTER STATE Aug 27 23:35:28 localhost Keepalived_vrrp[23052]: VRRP_Group(VG1) Syncing instances to MASTER state Aug 27 23:35:29 localhost Keepalived_vrrp[23052]: VRRP_Instance(VI_1) Entering MASTER STATE Aug 27 23:35:29 localhost Keepalived_vrrp[23052]: VRRP_Instance(VI_1) setting protocol VIPs. Aug 27 23:35:29 localhost Keepalived_healthcheckers[23051]: Netlink reflector reports IP 192.168.158.30 added Aug 27 23:35:29 localhost Keepalived_vrrp[23052]: VRRP_Instance(VI_1) Sending gratuitous ARPs on enp0s3 for 192.168.158.30 Aug 27 23:35:34 localhost Keepalived_vrrp[23052]: VRRP_Instance(VI_1) Sending gratuitous ARPs on enp0s3 for 192.168.158.30
# mysql_config_editor set --login-path=local --user=root --port=3306 --password# mysql_config_editor print --all