前言
MHA（Master High Availability）目前在MySQL高可用方面是一个相对成熟的解决方案，它由日本DeNA公司youshimaton(现就职于Facebook公司)开发，是一套优秀的作为MySQLy高可用环境下故障切换和主从提升的高可用软件。在MySQL故障切换过程中，MHA能做到在0~30秒之内自动完成数据库的故障切换操作，并且在进行故障切换过程中，MHA能在最大程度上保证数据的一致性，以达到真正意义上的高可用。
它由两部分组成：MHA Manager(管理节点)和MHA Node(数据节点)。MHA Manager可以单独部署在一台独立的机器上管理多个master-slave集群，也可以部署在一台slave上。
MHA node运行在每台MySQL服务器上，MHA Manager会定时探测集群中的master节点,当master 出现故障时，它可以自动将最新数据的slave提升为新的master,然后将所有其他的slave重新指向新的master。整个故障转移过程对应用程序是完全透明的。
1. 安装部署MHA前准备
MHA架构图
具体搭建如表：
角色 | IP地址 | 主机名 | serverID | 类型 |
Monitor host | 192.168.127.100 | MHA | 监控集群组 | |
Master | 192.168.127.101 | master | 101 | 写入 |
Candicate master | 192.168.127.102 | slave01 | 102 | 读 |
slave | 192.168.127.103 | slave02 | 103 | 读 |
vi /etc/hosts
127.0.0.1 localhost localhost.localdomain localhost4 localhost4.localdomain4
::1 localhost localhost.localdomain localhost6 localhost6.localdomain6
192.168.127.100 MHA
192.168.127.101 master
192.168.127.102 slave01
192.168.127.103 slave02
1.1． percona-mysql安装（master、slave01、slave02 三台安装）
注意：三台的server_id 不一样，为了做主从同步
创建mysql用户：
useradd mysql
创建安装目录与数据目录：
mkdir /app
mkdir -p /data/mysql3306
解决percona-mysql软件：
tar zxvf Percona-Server-5.6.27-rel75.0-Linux.x86_64.ssl101.tar.gz
注意：安装的软件需要根据openssl版本来下载
rpm -qa | grep ssl
openssl-1.0.1e-15.el6.x86_64
把解压文件移动相应目录：
mv Percona-Server-5.6.27-rel75.0-Linux.x86_64.ssl101 /app/mysql5.6
创建放慢查询日志目录：
mkdir /app/mysql5.6/logs
给目录权限：
chown -R mysql:mysql /app/mysql5.6
chown -R mysql:mysql /data/mysql3306
创建配置文件
vi /app/mysql5.6/my.cnf
[client]
socket=/app/mysql5.6/mysql.sock
default-character-set=utf8
port=3306
[mysql]
prompt=\\u@\\d \\r:\\m:\\s>
no-auto-rehash
[mysqld_safe]
log-error=/data/mysql3306/mysqld.error
[mysqld]
socket=/app/mysql5.6/mysql.sock
pid-file=/app/mysql5.6/mysqld.pid
basedir=/app/mysql5.6
datadir=/data/mysql3306
port=3306
server_id=101
character-set-server=utf8
skip-external-locking
skip-name-resolve
max_connections=1024
max_connect_errors=1000
wait_timeout = 400
interactive_timeout = 400
table_definition_cache=500
table_open_cache=500
sort_buffer_size = 16M
tmp_table_size = 200M
read_buffer_size = 1M
read_rnd_buffer_size = 4M
myisam_sort_buffer_size = 64M
thread_cache_size = 8
query_cache_type=0
query_cache_size=0
thread_concurrency = 16
lower_case_table_names = 1
log_bin_trust_function_creators = 1
#################slow log####################
slow-query_log=1
slow-query_log_file=/app/mysql5.6/logs/mysql.slow
long_query_time=2
####################binlog######################
log-bin=mysql-bin
binlog-format=ROW
expire_logs_days=5
sync_binlog=1
################replication##########
log-slave-updates=1
################INNODB################
sql_mode=NO_ENGINE_SUBSTITUTION,STRICT_TRANS_TABLES
transaction-isolation=READ-COMMITTED
innodb_buffer_pool_size=10G
innodb_flush_log_at_trx_commit=2
innodb_strict_mode=1
innodb_flush_method=O_DIRECT
innodb_file_format=Barracuda
innodb_log_files_in_group=3
innodb_file_per_table=1
innodb_io_capacity=500
innodb_support_xa=1
innodb_additional_mem_pool_size=16M
innodb_log_buffer_size=64M
[mysqldump]
quick
max_allowed_packet=128M
myisam_max_sort_sort_file_size=2G
初始化数据库
启动脚本
cp /app/mysql5.6/support-files/mysql.server /etc/init.d/mysql
vi /etc/init.d/mysql
basedir=/app/mysql5.6
datadir=/data/mysql3306
注意：修改以上两处即可
启动数据库
Starting MySQL (Percona Server).... [ OK ]
环境变量配置
vi /etc/profile
export MYSQL_HOME=/app/mysql5.6
export MY_baseDIR_VERSION=/app/mysql5.6
export PATH=/app/mysql5.6/bin:/app/mysql5.6/scripts:$PATH
export LD_LIBRARY_PATH=/app/mysql5.6/lib
生效环境变量
source /etc/profile
1.2 .主从同步搭建
注意：防火墙需要关闭
创建复制账号（master、slave1(mha新主)）
GRANT REPLICATION SLAVE ON *.* TO 'repl'@'192.168.127.%' IDENTIFIED BY 'repl';
flush privileges;
查看master binlog POS点信息
root@(none) 06:47:05>show master status;
+------------------+----------+--------------+------------------+-------------------+
| File | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+------------------+----------+--------------+------------------+-------------------+
| mysql-bin.000004 | 409 | | | |
+------------------+----------+--------------+------------------+-------------------+
1 row in set (0.01 sec)
建立主从复制（slave01、slave02）
[root@slave01 ~]# mysql
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 2
Server version: 5.6.27-75.0-log Percona Server (GPL), Release 75.0, Revision 8bb53b6
Copyright (c) 2009-2015 Percona LLC and/or its affiliates
Copyright (c) 2000, 2015, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
root@(none) 07:03:39>CHANGE MASTER TO MASTER_HOST='192.168.127.101',MASTER_PORT=3306,MASTER_USER='repl',MASTER_PASSWORD='repl',MASTER_LOG_FILE='mysql-bin.000004',MASTER_LOG_POS=409;
Query OK, 0 rows affected, 2 warnings (0.05 sec)
root@(none) 07:03:41>start slave;
Query OK, 0 rows affected (0.02 sec)
查看主从复制
root@(none) 07:03:42>show slave status\G;
*************************** 1. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: 192.168.127.101
Master_User: repl
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: mysql-bin.000004
Read_Master_Log_Pos: 409
Relay_Log_File: mysqld-relay-bin.000002
Relay_Log_Pos: 283
Relay_Master_Log_File: mysql-bin.000004
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
Replicate_Do_DB:
Replicate_Ignore_DB:
Replicate_Do_Table:
Replicate_Ignore_Table:
Replicate_Wild_Do_Table:
Replicate_Wild_Ignore_Table:
Last_Errno: 0
Last_Error:
Skip_Counter: 0
Exec_Master_Log_Pos: 409
Relay_Log_Space: 457
Until_Condition: None
Until_Log_File:
Until_Log_Pos: 0
Master_SSL_Allowed: No
Master_SSL_CA_File:
Master_SSL_CA_Path:
Master_SSL_Cert:
Master_SSL_Cipher:
Master_SSL_Key:
Seconds_Behind_Master: 0
Master_SSL_Verify_Server_Cert: No
Last_IO_Errno: 0
Last_IO_Error:
Last_SQL_Errno: 0
Last_SQL_Error:
Replicate_Ignore_Server_Ids:
Master_Server_Id: 101
Master_UUID: 8b1cf62d-e063-11e5-84ba-000c2908253f
Master_Info_File: /data/mysql3306/master.info
SQL_Delay: 0
SQL_Remaining_Delay: NULL
Slave_SQL_Running_State: Slave has read all relay log; waiting for the slave I/O thread to update it
Master_Retry_Count: 86400
Master_Bind:
Last_IO_Error_Timestamp:
Last_SQL_Error_Timestamp:
Master_SSL_Crl:
Master_SSL_Crlpath:
Retrieved_Gtid_Set:
Executed_Gtid_Set:
Auto_Position: 0
1 row in set (0.02 sec)
ERROR:
No query specified
以上主从已经搭建好，下面我们安装与配置MHA
（1）slave服务器(192.168.127.102,192.168.103)设置read only;
mysql> set global read_only=1;
（2）设置relay log清除方式（在每个slave 下）
mysql> set global relay_log_purge=0;
(3)创建监控用户,在所有MYSQL上执行
mysql> grant all privileges on *.* to 'root'@'192.168.127.%' identified by '123456';
mysql>flush privileges;
（4）在slave01(192.168.127.102)上创建复制用户：
mysql> grant replication slave on *.* to 'repl'@'192.168.127.%' identified by 'repl';
mysql>flush privileges;
2.安装部署MHA
2.1安装MHA node(在所有Mysql服务器上安装)
（1）安装依赖包
rpm -Uvh dl.fedoraproject.org/pub/epel/6/x86_64/epel-release-6-8.noarch.rpm
rpm --import /etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-6
yum -y install perl-DBD-MySQL perl-Config-Tiny perl-Log-Dispatch perl-Parallel-ForkManager perl-Config-IniFiles perl-Time-HiRes perl-Time-HiRes perl-CPAN
（2）在所有的节点上安装mha node:
tar zxvf mha4mysql-node-0.56.tar.gz
cd mha4mysql-node-0.56
perl Makefile.PL
make
make install
2.2.安装MHA Manager
MHA Manager中主要包括了几个管理员的命令行工具，例如masterha_manager，masterha_master_switch等。
（1） 安装依赖包
rpm -Uvh dl.fedoraproject.org/pub/epel/6/x86_64/epel-release-6-8.noarch.rpm
rpm --import /etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-6
yum -y install perl-DBD-MySQL perl-Config-Tiny perl-Log-Dispatch perl-Parallel-ForkManager perl-Config-IniFiles perl-Time-HiRes perl-Time-HiRes perl-CPAN
（2） 安装MHA node软件包。注意，在MHA Manger的主机上也要安装MHA node.
tar zxvf mha4mysql-node-0.56.tar.gz
cd mha4mysql-node-0.56
perl Makefile.PL
make
make install
（3） 安装MHA Manager软件包。
tar zxvf mha4mysql-manager-0.56.tar.gz
cd mha4mysql-manager-0.56
perl Makefile.PL
make
make install
2.3. 配置SSH 登录无密码验证
（1） 在manager （192.168.127.100）上配置到所有节点的无密码验证
ssh-keygen -t rsa
ssh-copy-id -i ~/.ssh/id_rsa.pub root@MHA
ssh-copy-id -i ~/.ssh/id_rsa.pub root@master
ssh-copy-id -i ~/.ssh/id_rsa.pub root@slave01
ssh-copy-id -i ~/.ssh/id_rsa.pub root@slave02
（2） 在MHA Node master(192.168.127.101)上：
ssh-keygen -t rsa
ssh-copy-id -i ~/.ssh/id_rsa.pub root@MHA
ssh-copy-id -i ~/.ssh/id_rsa.pub root@master
ssh-copy-id -i ~/.ssh/id_rsa.pub root@slave01
ssh-copy-id -i ~/.ssh/id_rsa.pub root@slave02
（3） 在MHA Node slave01(192.168.127.102)上：
ssh-keygen -t rsa
ssh-copy-id -i ~/.ssh/id_rsa.pub root@MHA
ssh-copy-id -i ~/.ssh/id_rsa.pub root@master
ssh-copy-id -i ~/.ssh/id_rsa.pub root@slave01
ssh-copy-id -i ~/.ssh/id_rsa.pub root@slave02
（4） 在MHA Node slave02(192.168.127.103)上：
ssh-keygen -t rsa
ssh-copy-id -i ~/.ssh/id_rsa.pub root@MHA
ssh-copy-id -i ~/.ssh/id_rsa.pub root@master
ssh-copy-id -i ~/.ssh/id_rsa.pub root@slave01
ssh-copy-id -i ~/.ssh/id_rsa.pub root@slave02
在每台做以下步骤
ln -s /app/mysql5.6/bin/* /usr/local/bin/
把脚本拷贝相关目录
[root@MHA ~]# cp /root/mha4mysql-manager-0.56/samples/scripts/master_ip_failover /usr/local/bin/
[root@MHA ~]# cp /root/mha4mysql-manager-0.56/samples/scripts/master_ip_online_change /usr/local/bin/
[root@MHA~]#cp /root/mha4mysql-manager-0.56/samples/scripts/send_report /usr/local/bin/
[root@MHA ~]# cp /root/mha4mysql-manager-0.56/bin/masterha_secondary_check /usr/bin/
3.配置MHA
配置MHA的步骤如下。
（1） 创建MHA工作目录，并且创建相关配置文件：
mkdir -p /etc/masterha
mkdir -p /masterha/app1
配置如下
vi /etc/masterha/app1.cnf
[server default]
manager_workdir=/masterha/app1
manager_log=/masterha/app1/app1.log
master_ip_failover_script=/usr/local/bin/master_ip_failover
master_ip_online_change_script=/usr/local/bin/master_ip_online_change
user=root
password=123456
ssh_user=root
repl_user=repl
repl_password=repl
ping_interval=1
remote_workdir=/tmp
report_script=/usr/local/bin/send_report
secondary_check_script=/usr/bin/masterha_secondary_check -s MHA -s slave02 --user=root --master_host=master --master_ip=192.168.127.101 --master_port=3306 --password=123456
shutdown_script=""
report_script=""
[server1]
hostname=192.168.127.101
master_binlog_dir=/data/mysql3306
candidate_master=1
[server2]
hostname=192.168.127.102
master_binlog_dir=/data/mysql3306
candidate_master=1
check_repl_delay=0
[server3]
hostname=192.168.127.103
master_binlog_dir=/data/mysql3306
no_master=1
4.检查SSH的配置
检查MHA Manager到所有MHA node的SSH连接状态：
[root@MHA ~]# masterha_check_ssh --conf=/etc/masterha/app1.cnf
Wed Mar 2 19:03:30 2016 - [warning] Global configuration file /etc/masterha_default.cnf not found. Skipping.
Wed Mar 2 19:03:30 2016 - [info] Reading application default configuration from /etc/masterha/app1.cnf..
Wed Mar 2 19:03:30 2016 - [info] Reading server configuration from /etc/masterha/app1.cnf..
Wed Mar 2 19:03:30 2016 - [info] Starting SSH connection tests..
Wed Mar 2 19:03:31 2016 - [debug]
Wed Mar 2 19:03:30 2016 - [debug] Connecting via SSH from root@192.168.127.101(192.168.127.101:22) to root@192.168.127.102(192.168.127.102:22)..
Wed Mar 2 19:03:30 2016 - [debug] ok.
Wed Mar 2 19:03:30 2016 - [debug] Connecting via SSH from root@192.168.127.101(192.168.127.101:22) to root@192.168.127.103(192.168.127.103:22)..
Wed Mar 2 19:03:30 2016 - [debug] ok.
Wed Mar 2 19:03:31 2016 - [debug]
Wed Mar 2 19:03:30 2016 - [debug] Connecting via SSH from root@192.168.127.102(192.168.127.102:22) to root@192.168.127.101(192.168.127.101:22)..
Wed Mar 2 19:03:31 2016 - [debug] ok.
Wed Mar 2 19:03:31 2016 - [debug] Connecting via SSH from root@192.168.127.102(192.168.127.102:22) to root@192.168.127.103(192.168.127.103:22)..
Wed Mar 2 19:03:31 2016 - [debug] ok.
Wed Mar 2 19:03:32 2016 - [debug]
Wed Mar 2 19:03:31 2016 - [debug] Connecting via SSH from root@192.168.127.103(192.168.127.103:22) to root@192.168.127.101(192.168.127.101:22)..
Wed Mar 2 19:03:31 2016 - [debug] ok.
Wed Mar 2 19:03:31 2016 - [debug] Connecting via SSH from root@192.168.127.103(192.168.127.103:22) to root@192.168.127.102(192.168.127.102:22)..
Wed Mar 2 19:03:32 2016 - [debug] ok.
Wed Mar 2 19:03:32 2016 - [info] All SSH connection tests passed successfully.
5.检查整个复制环境
[root@MHA ~]# masterha_check_ssh --conf=/etc/masterha/app1.cnf
Wed Mar 2 19:03:30 2016 - [warning] Global configuration file /etc/masterha_default.cnf not found. Skipping.
Wed Mar 2 19:03:30 2016 - [info] Reading application default configuration from /etc/masterha/app1.cnf..
Wed Mar 2 19:03:30 2016 - [info] Reading server configuration from /etc/masterha/app1.cnf..
Wed Mar 2 19:03:30 2016 - [info] Starting SSH connection tests..
Wed Mar 2 19:03:31 2016 - [debug]
Wed Mar 2 19:03:30 2016 - [debug] Connecting via SSH from root@192.168.127.101(192.168.127.101:22) to root@192.168.127.102(192.168.127.102:22)..
Wed Mar 2 19:03:30 2016 - [debug] ok.
Wed Mar 2 19:03:30 2016 - [debug] Connecting via SSH from root@192.168.127.101(192.168.127.101:22) to root@192.168.127.103(192.168.127.103:22)..
Wed Mar 2 19:03:30 2016 - [debug] ok.
Wed Mar 2 19:03:31 2016 - [debug]
Wed Mar 2 19:03:30 2016 - [debug] Connecting via SSH from root@192.168.127.102(192.168.127.102:22) to root@192.168.127.101(192.168.127.101:22)..
Wed Mar 2 19:03:31 2016 - [debug] ok.
Wed Mar 2 19:03:31 2016 - [debug] Connecting via SSH from root@192.168.127.102(192.168.127.102:22) to root@192.168.127.103(192.168.127.103:22)..
Wed Mar 2 19:03:31 2016 - [debug] ok.
Wed Mar 2 19:03:32 2016 - [debug]
Wed Mar 2 19:03:31 2016 - [debug] Connecting via SSH from root@192.168.127.103(192.168.127.103:22) to root@192.168.127.101(192.168.127.101:22)..
Wed Mar 2 19:03:31 2016 - [debug] ok.
Wed Mar 2 19:03:31 2016 - [debug] Connecting via SSH from root@192.168.127.103(192.168.127.103:22) to root@192.168.127.102(192.168.127.102:22)..
Wed Mar 2 19:03:32 2016 - [debug] ok.
Wed Mar 2 19:03:32 2016 - [info] All SSH connection tests passed successfully.
[root@MHA ~]# masterha_check_repl --conf=/etc/masterha/app1.cnf
Wed Mar 2 19:04:12 2016 - [warning] Global configuration file /etc/masterha_default.cnf not found. Skipping.
Wed Mar 2 19:04:12 2016 - [info] Reading application default configuration from /etc/masterha/app1.cnf..
Wed Mar 2 19:04:12 2016 - [info] Reading server configuration from /etc/masterha/app1.cnf..
Wed Mar 2 19:04:12 2016 - [info] MHA::MasterMonitor version 0.56.
Wed Mar 2 19:04:12 2016 - [info] GTID failover mode = 0
Wed Mar 2 19:04:12 2016 - [info] Dead Servers:
Wed Mar 2 19:04:12 2016 - [info] Alive Servers:
Wed Mar 2 19:04:12 2016 - [info] 192.168.127.101(192.168.127.101:3306)
Wed Mar 2 19:04:12 2016 - [info] 192.168.127.102(192.168.127.102:3306)
Wed Mar 2 19:04:12 2016 - [info] 192.168.127.103(192.168.127.103:3306)
Wed Mar 2 19:04:12 2016 - [info] Alive Slaves:
Wed Mar 2 19:04:12 2016 - [info] 192.168.127.102(192.168.127.102:3306) Version=5.6.27-75.0-log (oldest major version between slaves) log-bin:enabled
Wed Mar 2 19:04:12 2016 - [info] Replicating from 192.168.127.101(192.168.127.101:3306)
Wed Mar 2 19:04:12 2016 - [info] Primary candidate for the new Master (candidate_master is set)
Wed Mar 2 19:04:12 2016 - [info] 192.168.127.103(192.168.127.103:3306) Version=5.6.27-75.0-log (oldest major version between slaves) log-bin:enabled
Wed Mar 2 19:04:12 2016 - [info] Replicating from 192.168.127.101(192.168.127.101:3306)
Wed Mar 2 19:04:12 2016 - [info] Not candidate for the new Master (no_master is set)
Wed Mar 2 19:04:12 2016 - [info] Current Alive Master: 192.168.127.101(192.168.127.101:3306)
Wed Mar 2 19:04:12 2016 - [info] Checking slave configurations..
Wed Mar 2 19:04:12 2016 - [info] Checking replication filtering settings..
Wed Mar 2 19:04:12 2016 - [info] binlog_do_db= , binlog_ignore_db=
Wed Mar 2 19:04:12 2016 - [info] Replication filtering check ok.
Wed Mar 2 19:04:12 2016 - [info] GTID (with auto-pos) is not supported
Wed Mar 2 19:04:12 2016 - [info] Starting SSH connection tests..
Wed Mar 2 19:04:14 2016 - [info] All SSH connection tests passed successfully.
Wed Mar 2 19:04:14 2016 - [info] Checking MHA Node version..
Wed Mar 2 19:04:15 2016 - [info] Version check ok.
Wed Mar 2 19:04:15 2016 - [info] Checking SSH publickey authentication settings on the current master..
Wed Mar 2 19:04:15 2016 - [info] HealthCheck: SSH to 192.168.127.101 is reachable.
Wed Mar 2 19:04:15 2016 - [info] Master MHA Node version is 0.56.
Wed Mar 2 19:04:15 2016 - [info] Checking recovery script configurations on 192.168.127.101(192.168.127.101:3306)..
Wed Mar 2 19:04:15 2016 - [info] Executing command: save_binary_logs --command=test --start_pos=4 --binlog_dir=/data/mysql3306 --output_file=/tmp/save_binary_logs_test --manager_version=0.56 --start_file=mysql-bin.000004
Wed Mar 2 19:04:15 2016 - [info] Connecting to root@192.168.127.101(192.168.127.101:22)..
Creating /tmp if not exists.. ok.
Checking output directory is accessible or not..
ok.
Binlog found at /data/mysql3306, up to mysql-bin.000004
Wed Mar 2 19:04:15 2016 - [info] Binlog setting check done.
Wed Mar 2 19:04:15 2016 - [info] Checking SSH publickey authentication and checking recovery script configurations on all alive slave servers..
Wed Mar 2 19:04:15 2016 - [info] Executing command : apply_diff_relay_logs --command=test --slave_user='root' --slave_host=192.168.127.102 --slave_ip=192.168.127.102 --slave_port=3306 --workdir=/tmp --target_version=5.6.27-75.0-log --manager_version=0.56 --relay_log_info=/data/mysql3306/relay-log.info --relay_dir=/data/mysql3306/ --slave_pass=xxx
Wed Mar 2 19:04:15 2016 - [info] Connecting to root@192.168.127.102(192.168.127.102:22)..
Checking slave recovery environment settings..
Opening /data/mysql3306/relay-log.info ... ok.
Relay log found at /data/mysql3306, up to mysqld-relay-bin.000002
Temporary relay log file is /data/mysql3306/mysqld-relay-bin.000002
Testing mysql connection and privileges..Warning: Using a password on the command line interface can be insecure.
done.
Testing mysqlbinlog output.. done.
Cleaning up test file(s).. done.
Wed Mar 2 19:04:16 2016 - [info] Executing command : apply_diff_relay_logs --command=test --slave_user='root' --slave_host=192.168.127.103 --slave_ip=192.168.127.103 --slave_port=3306 --workdir=/tmp --target_version=5.6.27-75.0-log --manager_version=0.56 --relay_log_info=/data/mysql3306/relay-log.info --relay_dir=/data/mysql3306/ --slave_pass=xxx
Wed Mar 2 19:04:16 2016 - [info] Connecting to root@192.168.127.103(192.168.127.103:22)..
Checking slave recovery environment settings..
Opening /data/mysql3306/relay-log.info ... ok.
Relay log found at /data/mysql3306, up to mysqld-relay-bin.000002
Temporary relay log file is /data/mysql3306/mysqld-relay-bin.000002
Testing mysql connection and privileges..Warning: Using a password on the command line interface can be insecure.
done.
Testing mysqlbinlog output.. done.
Cleaning up test file(s).. done.
Wed Mar 2 19:04:16 2016 - [info] Slaves settings check done.
Wed Mar 2 19:04:16 2016 - [info]
+--192.168.127.102(192.168.127.102:3306)
+--192.168.127.103(192.168.127.103:3306)
Wed Mar 2 19:04:16 2016 - [info] Checking replication health on 192.168.127.102..
Wed Mar 2 19:04:16 2016 - [info] ok.
Wed Mar 2 19:04:16 2016 - [info] Checking replication health on 192.168.127.103..
Wed Mar 2 19:04:16 2016 - [info] ok.
Wed Mar 2 19:04:16 2016 - [info] Checking master_ip_failover_script status:
Wed Mar 2 19:04:16 2016 - [info] /usr/local/bin/master_ip_failover --command=status --ssh_user=root --orig_master_host=192.168.127.101 --orig_master_ip=192.168.127.101 --orig_master_port=3306
Bareword "FIXME_xxx" not allowed while "strict subs" in use at /usr/local/bin/master_ip_failover line 93.
Execution of /usr/local/bin/master_ip_failover aborted due to compilation errors.
Wed Mar 2 19:04:16 2016 - [error][/usr/local/share/perl5/MHA/MasterMonitor.pm, ln226] Failed to get master_ip_failover_script status with return code 255:0.
Wed Mar 2 19:04:16 2016 - [error][/usr/local/share/perl5/MHA/MasterMonitor.pm, ln424] Error happened on checking configurations. at /usr/local/bin/masterha_check_repl line 48
Wed Mar 2 19:04:16 2016 - [error][/usr/local/share/perl5/MHA/MasterMonitor.pm, ln523] Error happened on monitoring servers.
Wed Mar 2 19:04:16 2016 - [info] Got exit code 1 (Not master dead).
MySQL Replication Health is NOT OK!
说明以上没有成功需要修改以上的问题
把93行#FIXME_xxx; 注释掉
[root@MHA ~]# masterha_check_repl --conf=/etc/masterha/app1.cnf
Wed Mar 2 19:04:52 2016 - [warning] Global configuration file /etc/masterha_default.cnf not found. Skipping.
Wed Mar 2 19:04:52 2016 - [info] Reading application default configuration from /etc/masterha/app1.cnf..
Wed Mar 2 19:04:52 2016 - [info] Reading server configuration from /etc/masterha/app1.cnf..
Wed Mar 2 19:04:52 2016 - [info] MHA::MasterMonitor version 0.56.
Wed Mar 2 19:04:52 2016 - [info] GTID failover mode = 0
Wed Mar 2 19:04:52 2016 - [info] Dead Servers:
Wed Mar 2 19:04:52 2016 - [info] Alive Servers:
Wed Mar 2 19:04:52 2016 - [info] 192.168.127.101(192.168.127.101:3306)
Wed Mar 2 19:04:52 2016 - [info] 192.168.127.102(192.168.127.102:3306)
Wed Mar 2 19:04:52 2016 - [info] 192.168.127.103(192.168.127.103:3306)
Wed Mar 2 19:04:52 2016 - [info] Alive Slaves:
Wed Mar 2 19:04:52 2016 - [info] 192.168.127.102(192.168.127.102:3306) Version=5.6.27-75.0-log (oldest major version between slaves) log-bin:enabled
Wed Mar 2 19:04:52 2016 - [info] Replicating from 192.168.127.101(192.168.127.101:3306)
Wed Mar 2 19:04:52 2016 - [info] Primary candidate for the new Master (candidate_master is set)
Wed Mar 2 19:04:52 2016 - [info] 192.168.127.103(192.168.127.103:3306) Version=5.6.27-75.0-log (oldest major version between slaves) log-bin:enabled
Wed Mar 2 19:04:52 2016 - [info] Replicating from 192.168.127.101(192.168.127.101:3306)
Wed Mar 2 19:04:52 2016 - [info] Not candidate for the new Master (no_master is set)
Wed Mar 2 19:04:52 2016 - [info] Current Alive Master: 192.168.127.101(192.168.127.101:3306)
Wed Mar 2 19:04:52 2016 - [info] Checking slave configurations..
Wed Mar 2 19:04:52 2016 - [info] Checking replication filtering settings..
Wed Mar 2 19:04:52 2016 - [info] binlog_do_db= , binlog_ignore_db=
Wed Mar 2 19:04:52 2016 - [info] Replication filtering check ok.
Wed Mar 2 19:04:52 2016 - [info] GTID (with auto-pos) is not supported
Wed Mar 2 19:04:52 2016 - [info] Starting SSH connection tests..
Wed Mar 2 19:04:54 2016 - [info] All SSH connection tests passed successfully.
Wed Mar 2 19:04:54 2016 - [info] Checking MHA Node version..
Wed Mar 2 19:04:54 2016 - [info] Version check ok.
Wed Mar 2 19:04:54 2016 - [info] Checking SSH publickey authentication settings on the current master..
Wed Mar 2 19:04:54 2016 - [info] HealthCheck: SSH to 192.168.127.101 is reachable.
Wed Mar 2 19:04:55 2016 - [info] Master MHA Node version is 0.56.
Wed Mar 2 19:04:55 2016 - [info] Checking recovery script configurations on 192.168.127.101(192.168.127.101:3306)..
Wed Mar 2 19:04:55 2016 - [info] Executing command: save_binary_logs --command=test --start_pos=4 --binlog_dir=/data/mysql3306 --output_file=/tmp/save_binary_logs_test --manager_version=0.56 --start_file=mysql-bin.000004
Wed Mar 2 19:04:55 2016 - [info] Connecting to root@192.168.127.101(192.168.127.101:22)..
Creating /tmp if not exists.. ok.
Checking output directory is accessible or not..
ok.
Binlog found at /data/mysql3306, up to mysql-bin.000004
Wed Mar 2 19:04:55 2016 - [info] Binlog setting check done.
Wed Mar 2 19:04:55 2016 - [info] Checking SSH publickey authentication and checking recovery script configurations on all alive slave servers..
Wed Mar 2 19:04:55 2016 - [info] Executing command : apply_diff_relay_logs --command=test --slave_user='root' --slave_host=192.168.127.102 --slave_ip=192.168.127.102 --slave_port=3306 --workdir=/tmp --target_version=5.6.27-75.0-log --manager_version=0.56 --relay_log_info=/data/mysql3306/relay-log.info --relay_dir=/data/mysql3306/ --slave_pass=xxx
Wed Mar 2 19:04:55 2016 - [info] Connecting to root@192.168.127.102(192.168.127.102:22)..
Checking slave recovery environment settings..
Opening /data/mysql3306/relay-log.info ... ok.
Relay log found at /data/mysql3306, up to mysqld-relay-bin.000002
Temporary relay log file is /data/mysql3306/mysqld-relay-bin.000002
Testing mysql connection and privileges..Warning: Using a password on the command line interface can be insecure.
done.
Testing mysqlbinlog output.. done.
Cleaning up test file(s).. done.
Wed Mar 2 19:04:55 2016 - [info] Executing command : apply_diff_relay_logs --command=test --slave_user='root' --slave_host=192.168.127.103 --slave_ip=192.168.127.103 --slave_port=3306 --workdir=/tmp --target_version=5.6.27-75.0-log --manager_version=0.56 --relay_log_info=/data/mysql3306/relay-log.info --relay_dir=/data/mysql3306/ --slave_pass=xxx
Wed Mar 2 19:04:55 2016 - [info] Connecting to root@192.168.127.103(192.168.127.103:22)..
Checking slave recovery environment settings..
Opening /data/mysql3306/relay-log.info ... ok.
Relay log found at /data/mysql3306, up to mysqld-relay-bin.000002
Temporary relay log file is /data/mysql3306/mysqld-relay-bin.000002
Testing mysql connection and privileges..Warning: Using a password on the command line interface can be insecure.
done.
Testing mysqlbinlog output.. done.
Cleaning up test file(s).. done.
Wed Mar 2 19:04:55 2016 - [info] Slaves settings check done.
Wed Mar 2 19:04:55 2016 - [info]
+--192.168.127.102(192.168.127.102:3306)
+--192.168.127.103(192.168.127.103:3306)
Wed Mar 2 19:04:55 2016 - [info] Checking replication health on 192.168.127.102..
Wed Mar 2 19:04:55 2016 - [info] ok.
Wed Mar 2 19:04:55 2016 - [info] Checking replication health on 192.168.127.103..
Wed Mar 2 19:04:55 2016 - [info] ok.
Wed Mar 2 19:04:55 2016 - [info] Checking master_ip_failover_script status:
Wed Mar 2 19:04:55 2016 - [info] /usr/local/bin/master_ip_failover --command=status --ssh_user=root --orig_master_host=192.168.127.101 --orig_master_ip=192.168.127.101 --orig_master_port=3306
Wed Mar 2 19:04:55 2016 - [info] OK.
Wed Mar 2 19:04:55 2016 - [warning] shutdown_script is not defined.
Wed Mar 2 19:04:55 2016 - [info] Got exit code 0 (Not master dead).
MySQL Replication Health is OK.
说明成功
6.通过脚本管理 VIP
修改master_ip_failover文件（/usr/local/bin）
#!/usr/bin/env perl
# Copyright (C) 2011 DeNA Co.,Ltd.
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc.,
# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
## Note: This is a sample script and is not complete. Modify the script based on your environment.
use strict;
use warnings FATAL => 'all';
use Getopt::Long;
my (
$command, $ssh_user, $orig_master_host, $orig_master_ip,
$orig_master_port, $new_master_host, $new_master_ip, $new_master_port
);
my $vip='192.168.127.202/24';
my $key="2";
my $ssh_start_vip ="/sbin/ifconfig eth0:$key $vip";
my $ssh_stop_vip="/sbin/ifconfig eth0:$key down";
GetOptions(
'command=s' => \$command,
'ssh_user=s' => \$ssh_user,
'orig_master_host=s' => \$orig_master_host,
'orig_master_ip=s' => \$orig_master_ip,
'orig_master_port=i' => \$orig_master_port,
'new_master_host=s' => \$new_master_host,
'new_master_ip=s' => \$new_master_ip,
'new_master_port=i' => \$new_master_port,
);
exit &main();
sub main {
if ( $command eq "stop" || $command eq "stopssh" ) {
# $orig_master_host, $orig_master_ip, $orig_master_port are passed.
# If you manage master ip address at global catalog database,
# invalidate orig_master_ip here.
my $exit_code = 1;
eval {
print "Disabling the VIP on old master: $orig_master_host \n";
&stop_vip();
$exit_code = 0;
};
if ($@) {
warn "Got Error: $@\n";
exit $exit_code;
}
exit $exit_code;
}
elsif ( $command eq "start" ) {
# all arguments are passed.
# If you manage master ip address at global catalog database,
# activate new_master_ip here.
# You can also grant write access (create user, set read_only=0, etc) here.
my $exit_code = 10;
eval {
print "Enabling the VIP - $vip on the new master - $new_master_host \n";
&start_vip();
$exit_code = 0;
};
if ($@) {
warn $@;
# If you want to continue failover, exit 10.
exit $exit_code;
}
exit $exit_code;
}
elsif ( $command eq "status" ) {
print "Checking the Status of the script.. ok \n";
# do nothing
exit 0;
}
else {
&usage();
exit 1;
}
}
sub start_vip(){
`ssh $ssh_user\@$new_master_host \ " $ssh_start_vip \"`;
}
sub stop_vip(){
`ssh $ssh_user\@$orig_master_host \ " $ssh_stop_vip \"`;
}
sub usage {
print
"Usage: master_ip_failover --command=start|stop|stopssh|status --orig_master_host=host --orig_master_ip=ip --orig_master_port=port --new_master_host=host --new_master_ip=ip --new_master_port=port\n";
}
注意：首先启动VIP在192.168.127.101（master）上
7.开启MHA Manager监控
nohup masterha_manager --conf=/etc/masterha/app1.cnf > /masterha/app1/manager.log &1 &
8.查看启动状态
[root@MHA ~]# masterha_check_status --conf=/etc/masterha/app1.cnf
app1 (pid:27237) is running(0:PING_OK), master:192.168.127.101
9. 查看启动日志
[root@MHA ~]# tail -f /masterha/app1/app1.log
+--192.168.127.103(192.168.127.103:3306)
Wed Mar 2 19:08:34 2016 - [info] Checking master_ip_failover_script status:
Wed Mar 2 19:08:34 2016 - [info] /usr/local/bin/master_ip_failover --command=status --ssh_user=root --orig_master_host=192.168.127.101 --orig_master_ip=192.168.127.101 --orig_master_port=3306
Wed Mar 2 19:08:34 2016 - [info] OK.
Wed Mar 2 19:08:34 2016 - [warning] shutdown_script is not defined.
Wed Mar 2 19:08:34 2016 - [info] Set master ping interval 1 seconds.
Wed Mar 2 19:08:34 2016 - [info] Set secondary check script: /usr/bin/masterha_secondary_check -s MHA -s slave02 --user=root --master_host=master --master_ip=192.168.127.101 --master_port=3306 --password=123456
Wed Mar 2 19:08:34 2016 - [info] Starting ping health check on 192.168.127.101(192.168.127.101:3306)..
Wed Mar 2 19:08:34 2016 - [info] Ping(SELECT) succeeded, waiting until MySQL doesn't respond..
查看VIP
[root@master ~]# ip addr
1: lo:
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: eth0:
link/ether 00:0c:29:08:25:3f brd ff:ff:ff:ff:ff:ff
inet 192.168.127.101/24 brd 192.168.127.255 scope global eth0
inet 192.168.127.202/24 brd 192.168.127.255 scope global secondary eth0:2
inet6 fe80::20c:29ff:fe08:253f/64 scope link
valid_lft forever preferred_lft forever
3: pan0:
link/ether 0e:ed:39:ba:c1:1b brd ff:ff:ff:ff:ff:ff
10.测试切换
测试关闭主库
[root@master ~]# /etc/init.d/mysql stop
Shutting down MySQL (Percona Server)...... [ OK ]
查看slave02复制状态：
[root@slave02 ~]# mysql
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 27
Server version: 5.6.27-75.0-log Percona Server (GPL), Release 75.0, Revision 8bb53b6
Copyright (c) 2009-2015 Percona LLC and/or its affiliates
Copyright (c) 2000, 2015, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
root@(none) 07:42:08>show slave status\G;
*************************** 1. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: 192.168.127.102 #已经自动切换了
Master_User: repl
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: mysql-bin.000003
Read_Master_Log_Pos: 981
Relay_Log_File: mysqld-relay-bin.000002
Relay_Log_Pos: 283
Relay_Master_Log_File: mysql-bin.000003
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
Replicate_Do_DB:
Replicate_Ignore_DB:
Replicate_Do_Table:
Replicate_Ignore_Table:
Replicate_Wild_Do_Table:
Replicate_Wild_Ignore_Table:
Last_Errno: 0
Last_Error:
Skip_Counter: 0
Exec_Master_Log_Pos: 981
Relay_Log_Space: 457
Until_Condition: None
Until_Log_File:
Until_Log_Pos: 0
Master_SSL_Allowed: No
Master_SSL_CA_File:
Master_SSL_CA_Path:
Master_SSL_Cert:
Master_SSL_Cipher:
Master_SSL_Key:
Seconds_Behind_Master: 0
Master_SSL_Verify_Server_Cert: No
Last_IO_Errno: 0
Last_IO_Error:
Last_SQL_Errno: 0
Last_SQL_Error:
Replicate_Ignore_Server_Ids:
Master_Server_Id: 102
Master_UUID: 1bb38a96-e066-11e5-84cb-000c2976ee35
Master_Info_File: /data/mysql3306/master.info
SQL_Delay: 0
SQL_Remaining_Delay: NULL
Slave_SQL_Running_State: Slave has read all relay log; waiting for the slave I/O thread to update it
Master_Retry_Count: 86400
Master_Bind:
Last_IO_Error_Timestamp:
Last_SQL_Error_Timestamp:
Master_SSL_Crl:
Master_SSL_Crlpath:
Retrieved_Gtid_Set:
Executed_Gtid_Set:
Auto_Position: 0
1 row in set (0.00 sec)
ERROR:
No query specified
查看VIP漂移slave01(192.168.247.102)上
[root@slave01 ~]# ip addr
1: lo:
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: eth0:
link/ether 00:0c:29:76:ee:35 brd ff:ff:ff:ff:ff:ff
inet 192.168.127.102/24 brd 192.168.127.255 scope global eth0
inet 192.168.127.202/24 brd 192.168.127.255 scope global secondary eth0:2
inet6 fe80::20c:29ff:fe76:ee35/64 scope link
valid_lft forever preferred_lft forever
3: pan0:
link/ether 1e:77:57:63:5e:b0 brd ff:ff:ff:ff:ff:ff
10. 修改宕机的Master
通常情况自动切换后，原master 可能已经废弃掉，待原master 主机修改很复后，如果数据完整的情况，可能想把原master重新作为新主库的slave,这是我们就需要借助当时自动切换时刻的MHA日志来完成对原master的修复。下面是提取相关日志的命令：
[root@MHA ~]# grep -i 'change' /masterha/app1/app1.log
Wed Mar 2 19:09:23 2016 - [info] All other slaves should start replication from here. Statement should be: CHANGE MASTER TO MASTER_HOST='192.168.127.102', MASTER_PORT=3306, MASTER_LOG_FILE='mysql-bin.000003', MASTER_LOG_POS=981, MASTER_USER='repl', MASTER_PASSWORD='xxx';
Wed Mar 2 19:09:23 2016 - [info] Executed CHANGE MASTER.
11. 修复master变成从库
在master(192.168.127.101)操作如下：
[root@master ~]# /etc/init.d/mysql start
Starting MySQL (Percona Server).. [ OK ]
[root@master ~]# mysql
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 1
Server version: 5.6.27-75.0-log Percona Server (GPL), Release 75.0, Revision 8bb53b6
Copyright (c) 2009-2015 Percona LLC and/or its affiliates
Copyright (c) 2000, 2015, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
root@(none) 07:26:45>CHANGE MASTER TO MASTER_HOST='192.168.127.102', MASTER_PORT=3306, MASTER_LOG_FILE='mysql-bin.000003', MASTER_LOG_POS=981, MASTER_USER='repl', MASTER_PASSWORD='repl';
Query OK, 0 rows affected, 2 warnings (0.06 sec)
root@(none) 07:26:47>start slave;
Query OK, 0 rows affected (0.02 sec)
root@(none) 07:26:49>show slave status\G;
*************************** 1. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: 192.168.127.102
Master_User: repl
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: mysql-bin.000003
Read_Master_Log_Pos: 981
Relay_Log_File: mysqld-relay-bin.000002
Relay_Log_Pos: 283
Relay_Master_Log_File: mysql-bin.000003
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
Replicate_Do_DB:
Replicate_Ignore_DB:
Replicate_Do_Table:
Replicate_Ignore_Table:
Replicate_Wild_Do_Table:
Replicate_Wild_Ignore_Table:
Last_Errno: 0
Last_Error:
Skip_Counter: 0
Exec_Master_Log_Pos: 981
Relay_Log_Space: 457
Until_Condition: None
Until_Log_File:
Until_Log_Pos: 0
Master_SSL_Allowed: No
Master_SSL_CA_File:
Master_SSL_CA_Path:
Master_SSL_Cert:
Master_SSL_Cipher:
Master_SSL_Key:
Seconds_Behind_Master: 0
Master_SSL_Verify_Server_Cert: No
Last_IO_Errno: 0
Last_IO_Error:
Last_SQL_Errno: 0
Last_SQL_Error:
Replicate_Ignore_Server_Ids:
Master_Server_Id: 102
Master_UUID: 1bb38a96-e066-11e5-84cb-000c2976ee35
Master_Info_File: /data/mysql3306/master.info
SQL_Delay: 0
SQL_Remaining_Delay: NULL
Slave_SQL_Running_State: Slave has read all relay log; waiting for the slave I/O thread to update it
Master_Retry_Count: 86400
Master_Bind:
Last_IO_Error_Timestamp:
Last_SQL_Error_Timestamp:
Master_SSL_Crl:
Master_SSL_Crlpath:
Retrieved_Gtid_Set:
Executed_Gtid_Set:
Auto_Position: 0
1 row in set (0.00 sec)
ERROR:
No query specified
12. 开启新的MHA Manager监控
[root@MHA ~]# cd /etc/masterha/
[root@MHA masterha]# cp app1.cnf app2.cnf
修改配置如下，注意：红色是修改地方
[root@MHA masterha]# vi app2.cnf
[server default]
manager_workdir=/masterha/app1
manager_log=/masterha/app1/app1.log
master_ip_failover_script=/usr/local/bin/master_ip_failover
master_ip_online_change_script=/usr/local/bin/master_ip_online_change
user=root
password=123456
ssh_user=root
repl_user=repl
repl_password=repl
ping_interval=1
remote_workdir=/tmp
report_script=/usr/local/bin/send_report
secondary_check_script=/usr/bin/masterha_secondary_check -s master -s slave01 --user=root --master_host=slave01 --master_ip=192.168.127.102 --master_port=3306 --password=123456
shutdown_script=""
report_script=""
[server1]
hostname=192.168.127.102
master_binlog_dir=/data/mysql3306
candidate_master=1
[server2]
hostname=192.168.127.101
master_binlog_dir=/data/mysql3306
candidate_master=1
check_repl_delay=0
[server3]
hostname=192.168.127.103
master_binlog_dir=/data/mysql3306
no_master=1
查看
[root@MHA masterha]# masterha_check_status --conf=/etc/masterha/app1.cnf
app1 is stopped(2:NOT_RUNNING).
启动新的MHA监控
[root@MHA masterha]# nohup masterha_manager --conf=/etc/masterha/app2.cnf > /masterha/app1/manager.log &1 &
[1] 2089
查看启动状态
[root@MHA masterha]# masterha_check_status --conf=/etc/masterha/app2.cnf
app2 (pid:2089) is running(0:PING_OK), master:192.168.127.102
以上测试成功，为了保证稳定，反复测试一下。
13.MHA+半同步复制
为了保证数据一致性采用半同步复制
（1）Master(192.168.127.101),slave01(192.168.127.102)操作如下：
执行安装相关插入件启动半同步复制
INSTALL PLUGIN rpl_semi_sync_master SonAME 'semisync_master.so';
SET GLOBAL rpl_semi_sync_master_enabled=1;
SET GLOBAL rpl_semi_sync_master_timeout=10000;
切换时也可能当作从库，所以也操作如下步骤
INSTALL PLUGIN rpl_semi_sync_slave SonAME 'semisync_slave.so';
SET GLOBAL rpl_semi_sync_slave_enabled=1;
在配置文件my.cnf增加以下参数
#############半同步###########
rpl_semi_sync_master_enabled=1
rpl_semi_sync_master_timeout=1000
rpl_semi_sync_master_trace_level=32
rpl_semi_sync_master_wait_no_slave=on
rpl_semi_sync_slave_enabled=1
#################################
（2） 所以的从都操作如下：
Slave02(192.168.127.102)的操作
执行安装相关插入件启动半同步复制
INSTALL PLUGIN rpl_semi_sync_slave SonAME 'semisync_slave.so';
SET GLOBAL rpl_semi_sync_slave_enabled=1;
在配置文件my.cnf增加以下参数
#############半同步###########
rpl_semi_sync_slave_enabled=1
#################################
以上配置成功，不需要重启
查看主库的半同步
root@(none) 11:36:36>show variables like 'rpl%';
+------------------------------------+----------+
| Variable_name | Value |
+------------------------------------+----------+
| rpl_semi_sync_master_enabled | ON |
| rpl_semi_sync_master_timeout | 10000 |
| rpl_semi_sync_master_trace_level | 32 |
| rpl_semi_sync_master_wait_no_slave | ON |
| rpl_semi_sync_slave_enabled | ON |
| rpl_semi_sync_slave_trace_level | 32 |
| rpl_stop_slave_timeout | 31536000 |
+------------------------------------+----------+
7 rows in set (0.01 sec)
查看从库的半同步
root@(none) 11:36:36>show variables like 'rpl%';
+---------------------------------+----------+
| Variable_name | Value |
+---------------------------------+----------+
| rpl_semi_sync_slave_enabled | ON |
| rpl_semi_sync_slave_trace_level | 32 |
| rpl_stop_slave_timeout | 31536000 |
+---------------------------------+----------+
3 rows in set (0.01 sec)