MySQL+MHA的高可用集群解决方案

￡神魔★判官ぃ 2022-02-02 05:11 366阅读 0赞

> 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公司的youshimaton（现就职于Facebook公司）开发，是一套优秀的作为MySQL高可用性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的过程中，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。

该软件由两部分组成：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节点上。

> 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完全透明。

> 在MHA自动故障切换过程中，MHA试图从宕机的主服务器上保存二进制日志，最大程度的保证数据的不丢失，但这并不总是可行的。例如，如果主服务器硬件故障或无法通过ssh访问，MHA没法保存二进制日志，只进行故障转移而丢失了最新的数据。使用MySQL 5.5的半同步复制，可以大大降低数据丢失的风险。MHA可以与半同步复制结合起来。如果只有一个slave已经收到了最新的二进制日志，MHA可以将最新的二进制日志应用于其他所有的slave服务器上，因此可以保证所有节点的数据一致性。

> 目前MHA主要支持一主多从的架构。要搭建MHA，要求一个复制集群中必须最少有三台数据库服务器，一主二从，即一台充当master，一台充当备用master，另外一台充当从库。因为至少需要三台服务器，出于机器成本的考虑，淘宝也在该基础上进行了改造，目前淘宝TMHA已经支持一主一从。

### 一、MHA工作原理、功能 ###

### 1、MHA工作原理总结为以下几条： ###

*  从宕机崩溃的master保存二进制日志事件（binlog events）；
 *  识别含有最新更新的slave；
 *  应用差异的中继日志（relay log）到其他slave；
 *  应用从master保存的二进制日志事件（binlog events）；
 *  提升一个slave为新master；
 *  使用其他的slave连接新的master进行复制。

#### 2、MHA提供了如下功能： ####

（1）master自动监控，故障转移一体化(Automated master monitoring and failover)

（2）MHA可以在一个复制组中监控master的状态，如果挂了，就可以自动的做failover。

（3）MHA通过所有slave的差异relay-log来保证数据的一致性。

（4）MHA在做故障转移，日志补偿这些动作的时候，通常只需要10~30秒。

（5）通常情况下，MHA会选择最新的slave作为new master，但是你也可以指定哪些是候选maser，那么新master选举的时候，就从这些host里面挑。

（6）导致复制环境中断的一致性问题，在MHA中是不会发生的，请放心使用。  
在MHA自动故障切换过程中，MHA试图从宕机的主服务器上保存二进制日志，最大程度的保证数据的不丢失，但这并不总是可行的。例如，如果主服务器硬件故障或无法通过ssh访问，MHA没法保存二进制日志，只进行故障转移而丢失了最新的数据。使用MySQL 5.5及以上版本的半同步复制，可以大大降低数据丢失的风险。MHA可以与半同步复制结合起来。如果只有一个slave已经收到了最新的二进制日志，MHA可以将最新的二进制日志应用于其他所有的slave服务器上，因此可以保证所有节点的数据一致性。

（7）手工-交互式master故障转移（Interactive manually initiated Master Failover）

MHA可以配置成手工-交互式方式进行故障转移，不支持监控master的状态。

（8）非交互式master故障转移 （Non-interactive master failover）

非交互式，自动的故障转移，不提供监控master状态功能，监控可以交给其他组件做（如：Pacemaker heartbeat）。

（9）在线master切换 （Online switching master to a different host）

### 二、MHA组件介绍 ###

MHA组件介绍MHA软件由两部分组成，Manager工具包和Node工具包，具体的说明如下。

Manager工具包主要包括以下几个工具：

（1）masterha\_check\_ssh \#检查MHA的SSH配置状况;

（2）masterha\_check\_repl \#检查MySQL复制状况;

（3）masterha\_manger \#启动MHA;

（4）masterha\_check\_status \#检测当前MHA运行状态;

（5）masterha\_master\_monitor \#检测master是否宕机;

（6）masterha\_master\_switch \#控制故障转移(自动或者手动);

（7）masterha\_conf\_host \#添加或删除配置的server信息;

Node工具包（这些工具通常由MHA Manager的脚本触发，无需人为操作）主要包括以下几个工具：

（1）save\_binary\_logs \#保存和复制master的二进制日志;

（2）apply\_diff\_relay\_logs \#识别差异的中继日志事件并将其差异的事件应用于其他的slave;

（3）purge\_relay\_logs \#清除中继日志（不会阻塞SQL线程）;

注意： 为了尽可能的减少主库硬件损坏宕机造成的数据丢失，因此在配置MHA的同时建议配置成MySQL半同步复制

环境：

*  server1：172.25.70.1
 *  server2：172.25.70.2
 *  server3：172.25.70.3

### 三、搭建基于MySQL的MHA ###

#### 1.关闭server1-3的mysqld服务；修改server1、server2、server3的msyqld配置文件 ####

*  server1-3:

systemctl stop mysqld

*  server1:

vim /etc/my.cnf
    =================
     29 server_id=1
     30 gtid_mode=ON
     31 enforce_gtid_consistency=ON
     32 log_slave_updates=ON
     33 log_bin=binlog

*  server2:

vim /etc/my.cnf
    ===================
     29 server-id=2
     30 gtid_mode=ON
     31 enforce_gtid_consistency=ON
     32 log_slave_updates=ON
     33 log_bin=binlog

*  server3:

vim /etc/my.cnf
    ====================
     29 server-id=3
     30 gtid_mode=ON
     31 enforce_gtid_consistency=ON
     32 log_slave_updates=ON
     33 log_bin=binlog

#### 2.初始化server3的mysqld服务 ####

[root@server3 ~]# cd /var/lib/mysql
    [root@server3 mysql]# ls
    auto.cnf       binlog.index     ib_buffer_pool  performance_schema  sys
    binlog.000001  ca-key.pem       ibdata1         private_key.pem
    binlog.000002  ca.pem           ib_logfile0     public_key.pem
    binlog.000003  client-cert.pem  ib_logfile1     server-cert.pem
    binlog.000004  client-key.pem   mysql           server-key.pem
    [root@server3 mysql]# rm -fr *
    [root@server3 mysql]# systemctl start mysqld
    [root@server3 mysql]# cat /var/log/mysqld.log | grep password
    ==============================================================================
    2019-05-03T00:04:13.360192Z 1 [Note] A temporary password is generated for root@localhost: (kkw=D?1,fu2
    2019-05-03T01:11:12.145588Z 0 [Note] Shutting down plugin 'validate_password'
    2019-05-03T01:11:13.674624Z 0 [Note] Shutting down plugin 'sha256_password'
    2019-05-03T01:11:13.674629Z 0 [Note] Shutting down plugin 'mysql_native_passwor'
    2019-05-03T03:01:23.405961Z 0 [Note] Shutting down plugin 'validate_password'
    2019-05-03T03:01:24.718329Z 0 [Note] Shutting down plugin 'sha256_password'
    2019-05-03T03:01:24.718331Z 0 [Note] Shutting down plugin 'mysql_native_passwor'
    2019-05-03T03:08:43.045997Z 1 [Note] A temporary password is generated for root@localhost: MkT>18/5CK=)
    ==============================================================================
    [root@server3 mysql]# mysql -p
    Enter password: 
    Welcome to the MySQL monitor.  Commands end with ; or \g.
    Your MySQL connection id is 2
    Server version: 5.7.24-log
    
    Copyright (c) 2000, 2018, 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.
    
    mysql> alter user root@localhost identified by 'Mahao+123';
    Query OK, 0 rows affected (0.01 sec)
    
    mysql> SHOW DATABASES;
    +--------------------+
    | Database           |
    +--------------------+
    | information_schema |
    | mysql              |
    | performance_schema |
    | sys                |
    +--------------------+
    4 rows in set (0.00 sec)

#### 3.为server3设置复制用户，并开启server3的slave线程 ####

mysql> change master to master_host='172.25.13.1',master_user='rep',master_password='Mahao+123',master_auto_position=1;
    Query OK, 0 rows affected, 2 warnings (0.04 sec)
    
    mysql> start slave;
    Query OK, 0 rows affected (0.00 sec)
    
    mysql> SHOW SLAVE STATUS\G
    *************************** 1. row ***************************
                   Slave_IO_State: Waiting for master to send event
                      Master_Host: 172.25.13.1
                      Master_User: rep
                      Master_Port: 3306
                    Connect_Retry: 60
                  Master_Log_File: binlog.000006
              Read_Master_Log_Pos: 526
                   Relay_Log_File: server3-relay-bin.000008
                    Relay_Log_Pos: 485
            Relay_Master_Log_File: binlog.000006
                 Slave_IO_Running: Yes
                Slave_SQL_Running: Yes

\#测试

#### 4.主库写入信息 ####

*  server1:

#### 5.从库查看 ####

*  server3:

[root@server3 mysql]# mysql -p
    Enter password: 
    Welcome to the MySQL monitor.  Commands end with ; or \g.
    Your MySQL connection id is 7
    Server version: 5.7.24-log MySQL Community Server (GPL)
    
    Copyright (c) 2000, 2018, 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.
    
    mysql> SHOW DATABASES;
    +--------------------+
    | Database           |
    +--------------------+
    | information_schema |
    | mysql              |
    | performance_schema |
    | sys                |
    | taylor             |
    +--------------------+
    5 rows in set (0.00 sec)
    
    mysql> use taylor
    Reading table information for completion of table and column names
    You can turn off this feature to get a quicker startup with -A
    
    Database changed
    mysql> select * from usertb;
    +----------+----------+
    | username | password |
    +----------+----------+
    | user1    | 123      |
    +----------+----------+
    1 row in set (0.00 sec)

*  server1:

mysql> SHOW GLOBAL VARIABLES LIKE '%gtid%';
    +----------------------------------+------------------------------------------------------------------------------------+
    | Variable_name                    | Value                                                                              |
    +----------------------------------+------------------------------------------------------------------------------------+
    | binlog_gtid_simple_recovery      | ON                                                                                 |
    | enforce_gtid_consistency         | ON                                                                                 |
    | gtid_executed                    | 742e05c2-6cad-11e9-a66b-52540075b0d5:1-8,
    f32c0a71-6c6f-11e9-8a9f-52540075b0d5:1-7 |
    | gtid_executed_compression_period | 1000                                                                               |
    | gtid_mode                        | ON                                                                                 |
    | gtid_owned                       |                                                                                    |
    | gtid_purged                      |                                                                                    |
    | session_track_gtids              | OFF                                                                                |
    +----------------------------------+------------------------------------------------------------------------------------+
    8 rows in set (0.00 sec)
    
    mysqldump --all-databases --single-transaction --triggers --routines --events --host=127.0.0.1 --port=3306 --user=root --password=Mahao+123 > Mahao.sql

*  server4:

### 安装MHA ###

[root@server4 ~]# ls
    MHA-7
    [root@server4 ~]# cd 
    .config/ .local/  MHA-7/   .ssh/    
    [root@server4 ~]# cd MHA-7/
    [root@server4 MHA-7]# ls
    mha4mysql-manager-0.58-0.el7.centos.noarch.rpm
    mha4mysql-manager-0.58.tar.gz
    mha4mysql-node-0.58-0.el7.centos.noarch.rpm
    perl-Config-Tiny-2.14-7.el7.noarch.rpm
    perl-Email-Date-Format-1.002-15.el7.noarch.rpm
    perl-Log-Dispatch-2.41-1.el7.1.noarch.rpm
    perl-Mail-Sender-0.8.23-1.el7.noarch.rpm
    perl-Mail-Sendmail-0.79-21.el7.noarch.rpm
    perl-MIME-Lite-3.030-1.el7.noarch.rpm
    perl-MIME-Types-1.38-2.el7.noarch.rpm
    perl-Parallel-ForkManager-1.18-2.el7.noarch.rpm

#### 1.先安装依赖 ####

[root@server4 MHA-7]# yum install -y perl*

#### 2.安装MHA ####

[root@server4 MHA-7]# yum install -y mha4mysql-manager-0.58-0.el7.centos.noarch.rpm mha4mysql-node-0.58-0.el7.centos.noarch.rpm

#### 3.生成ssh验证密钥 ####

[root@server4 MHA-7]# ssh-keygen
    Generating public/private rsa key pair.
    Enter file in which to save the key (/root/.ssh/id_rsa): 
    Enter passphrase (empty for no passphrase): 
    Enter same passphrase again: 
    Your identification has been saved in /root/.ssh/id_rsa.
    Your public key has been saved in /root/.ssh/id_rsa.pub.
    The key fingerprint is:
    ea:fd:44:c4:e1:41:20:10:d4:d7:b5:d4:ba:f5:08:69 root@server4
    The key's randomart image is:
    +--[ RSA 2048]----+
    |   .++. .++.o.   |
    |      ...o.+ ..  |
    |       .  + .o   |
    |         .  E .  |
    |        S .. + o |
    |       . .  . . .|
    |      .   .      |
    |     . . .       |
    |      . ...      |
    +-----------------+

#### 4.发送公钥到server1—server3 ####

ssh-copy-id server1
    ssh-copy-id server2
    ssh-copy-id server3

\#验证

ssh server1
    ssh server2
    ssh server3

#### 5.给server1-3发送mha4mysql-node-0.58-0.el7.centos.noarch.rpm，并安装 ####

[root@server1 ~]# yum install -y mha4mysql-node-0.58-0.el7.centos.noarch.rpm
    
    [root@server2 ~]# yum install -y mha4mysql-node-0.58-0.el7.centos.noarch.rpm
    
    [root@server3 ~]# yum install -y mha4mysql-node-0.58-0.el7.centos.noarch.rpm

#### 6.server4创建目录，并编写配置文件 ####

[root@server4 MHA-7]# mkdir -p /etc/masterha
    [root@server4 MHA-7]# cd /etc/masterha/
    [root@server4 masterha]# ls
    [root@server4 masterha]# 
    [root@server4 masterha]# vim app1.cnf
    =============================================
    [server default]
    manager_workdir=/etc/masterha
    manager_log=/var/log/masterha.log
    master_binlog_dir=/etc/masterha
    #master_ip_failover_script= /usr/local/bin/master_ip_failover
    #master_ip_online_change_script= /usr/local/bin/master_ip_online_change
    password=Mahao+123
    user=root
    ping_interval=1
    remote_workdir=/tmp
    repl_password=Mahao+123
    repl_user=repl
    #report_script=/usr/local/send_report
    #secondary_check_script= /usr/local/bin/masterha_secondary_check -s server03 -s server02
    #shutdown_script=""
    ssh_user=root
    
    [server1]
    hostname=172.25.13.1
    port=3306
    [server2]
    hostname=172.25.13.2
    port=3306
    candidate_master=1
    check_repl_delay=0
    
    [server3]
    hostname=172.25.13.3
    port=3306
    no_master=1

#### 7.ssh验证 ####

[root@server4 masterha]# masterha_check_ssh --conf=/etc/masterha/app1.cnf
    Fri May  3 14:27:19 2019 - [warning] Global configuration file /etc/masterha_default.cnf not found. Skipping.
    Fri May  3 14:27:19 2019 - [info] Reading application default configuration from /etc/masterha/app1.cnf..
    Fri May  3 14:27:19 2019 - [info] Reading server configuration from /etc/masterha/app1.cnf..
    Fri May  3 14:27:19 2019 - [info] Starting SSH connection tests..
    Fri May  3 14:27:19 2019 - [error][/usr/share/perl5/vendor_perl/MHA/SSHCheck.pm, ln63] 
    Fri May  3 14:27:19 2019 - [debug]  Connecting via SSH from root@172.25.13.1(172.25.13.1:22) to root@172.25.13.2(172.25.13.2:22)..
    Permission denied (publickey,gssapi-keyex,gssapi-with-mic,password).
    Fri May  3 14:27:19 2019 - [error][/usr/share/perl5/vendor_perl/MHA/SSHCheck.pm, ln111] SSH connection from root@172.25.13.1(172.25.13.1:22) to root@172.25.13.2(172.25.13.2:22) failed!
    Fri May  3 14:27:20 2019 - [error][/usr/share/perl5/vendor_perl/MHA/SSHCheck.pm, ln63] 
    Fri May  3 14:27:19 2019 - [debug]  Connecting via SSH from root@172.25.13.2(172.25.13.2:22) to root@172.25.13.1(172.25.13.1:22)..
    Warning: Permanently added '172.25.13.1' (ECDSA) to the list of known hosts.
    Permission denied (publickey,gssapi-keyex,gssapi-with-mic,password).
    Fri May  3 14:27:19 2019 - [error][/usr/share/perl5/vendor_perl/MHA/SSHCheck.pm, ln111] SSH connection from root@172.25.13.2(172.25.13.2:22) to root@172.25.13.1(172.25.13.1:22) failed!
    Fri May  3 14:27:20 2019 - [error][/usr/share/perl5/vendor_perl/MHA/SSHCheck.pm, ln63] 
    Fri May  3 14:27:20 2019 - [debug]  Connecting via SSH from root@172.25.13.3(172.25.13.3:22) to root@172.25.13.1(172.25.13.1:22)..
    Warning: Permanently added '172.25.13.1' (ECDSA) to the list of known hosts.
    Permission denied (publickey,gssapi-keyex,gssapi-with-mic,password).
    Fri May  3 14:27:20 2019 - [error][/usr/share/perl5/vendor_perl/MHA/SSHCheck.pm, ln111] SSH connection from root@172.25.13.3(172.25.13.3:22) to root@172.25.13.1(172.25.13.1:22) failed!
    SSH Configuration Check Failed!
     at /usr/bin/masterha_check_ssh line 44.

#### 8.给server1-3发送/root/.ssh/目录 ####

[root@server4 masterha]# scp -r ~/.ssh server1:
    known_hosts                                          100%  718     0.7KB/s   00:00    
    authorized_keys                                      100%  831     0.8KB/s   00:00    
    id_rsa                                               100% 1675     1.6KB/s   00:00    
    id_rsa.pub                                           100%  394     0.4KB/s   00:00    
    [root@server4 masterha]# scp -r ~/.ssh server2:
    known_hosts                                          100%  718     0.7KB/s   00:00    
    authorized_keys                                      100%  831     0.8KB/s   00:00    
    id_rsa                                               100% 1675     1.6KB/s   00:00    
    id_rsa.pub                                           100%  394     0.4KB/s   00:00    
    [root@server4 masterha]# scp -r ~/.ssh server3:
    known_hosts                                          100%  718     0.7KB/s   00:00    
    authorized_keys                                      100%  831     0.8KB/s   00:00    
    id_rsa                                               100% 1675     1.6KB/s   00:00    
    id_rsa.pub               
    
    =====================================================================================
    #自己特殊设定的解决方式
    
    
    [root@server4 masterha]# cd ~/.ssh/
    [root@server4 .ssh]# ls
    authorized_keys  id_rsa  id_rsa.pub  known_hosts
    [root@server4 .ssh]# scp id_rsa id_rsa.pub known_hosts server1:~/.ssh/
    id_rsa                                               100% 1675     1.6KB/s   00:00    
    id_rsa.pub                                           100%  394     0.4KB/s   00:00    
    known_hosts                                          100%  718     0.7KB/s   00:00    
    [root@server4 .ssh]# scp id_rsa id_rsa.pub known_hosts server2:~/.ssh/
    id_rsa                                               100% 1675     1.6KB/s   00:00    
    id_rsa.pub                                           100%  394     0.4KB/s   00:00    
    known_hosts                                          100%  718     0.7KB/s   00:00    
    [root@server4 .ssh]# scp id_rsa id_rsa.pub known_hosts server3:~/.ssh/
    id_rsa                                               100% 1675     1.6KB/s   00:00    
    id_rsa.pub                                           100%  394     0.4KB/s   00:00    
    known_hosts                                          100%  718     0.7KB/s   00:00    
    [root@server4 .ssh]# 
    ======================================================================================

再次检测ssh

[root@server4 .ssh]# masterha_check_ssh --conf=/etc/masterha/app1.cnf
    Fri May  3 14:40:44 2019 - [warning] Global configuration file /etc/masterha_default.cnf not found. Skipping.
    Fri May  3 14:40:44 2019 - [info] Reading application default configuration from /etc/masterha/app1.cnf..
    Fri May  3 14:40:44 2019 - [info] Reading server configuration from /etc/masterha/app1.cnf..
    Fri May  3 14:40:44 2019 - [info] Starting SSH connection tests..
    Fri May  3 14:40:44 2019 - [debug] 
    Fri May  3 14:40:44 2019 - [debug]  Connecting via SSH from root@172.25.13.1(172.25.13.1:22) to root@172.25.13.2(172.25.13.2:22)..
    Fri May  3 14:40:44 2019 - [debug]   ok.
    Fri May  3 14:40:44 2019 - [debug]  Connecting via SSH from root@172.25.13.1(172.25.13.1:22) to root@172.25.13.3(172.25.13.3:22)..
    Fri May  3 14:40:44 2019 - [debug]   ok.
    Fri May  3 14:40:45 2019 - [debug] 
    Fri May  3 14:40:44 2019 - [debug]  Connecting via SSH from root@172.25.13.2(172.25.13.2:22) to root@172.25.13.1(172.25.13.1:22)..
    Fri May  3 14:40:44 2019 - [debug]   ok.
    Fri May  3 14:40:44 2019 - [debug]  Connecting via SSH from root@172.25.13.2(172.25.13.2:22) to root@172.25.13.3(172.25.13.3:22)..
    Fri May  3 14:40:44 2019 - [debug]   ok.
    Fri May  3 14:40:45 2019 - [debug] 
    Fri May  3 14:40:45 2019 - [debug]  Connecting via SSH from root@172.25.13.3(172.25.13.3:22) to root@172.25.13.1(172.25.13.1:22)..
    Fri May  3 14:40:45 2019 - [debug]   ok.
    Fri May  3 14:40:45 2019 - [debug]  Connecting via SSH from root@172.25.13.3(172.25.13.3:22) to root@172.25.13.2(172.25.13.2:22)..
    Fri May  3 14:40:45 2019 - [debug]   ok.
    Fri May  3 14:40:45 2019 - [info] All SSH connection tests passed successfully.
    [root@server4 .ssh]#

检测repl

[root@server4 .ssh]# masterha_check_repl --conf=/etc/masterha/app1.cnf
    ==========================================================================
    Fri May  3 14:43:04 2019 - [warning] Global configuration file /etc/masterha_default.cnf not found. Skipping.
    Fri May  3 14:43:04 2019 - [info] Reading application default configuration from /etc/masterha/app1.cnf..
    Fri May  3 14:43:04 2019 - [info] Reading server configuration from /etc/masterha/app1.cnf..
    Fri May  3 14:43:04 2019 - [info] MHA::MasterMonitor version 0.58.
    Fri May  3 14:43:05 2019 - [error][/usr/share/perl5/vendor_perl/MHA/ServerManager.pm, ln188] There is no alive server. We can't do failover
    Fri May  3 14:43:05 2019 - [error][/usr/share/perl5/vendor_perl/MHA/MasterMonitor.pm, ln427] Error happened on checking configurations.  at /usr/share/perl5/vendor_perl/MHA/MasterMonitor.pm line 329.
    Fri May  3 14:43:05 2019 - [error][/usr/share/perl5/vendor_perl/MHA/MasterMonitor.pm, ln525] Error happened on monitoring servers.
    Fri May  3 14:43:05 2019 - [info] Got exit code 1 (Not master dead).
    
    MySQL Replication Health is NOT OK!

\#有报错

server1提供授权

*  server1:

[root@server1 ~]# systemctl start mysqld
    [root@server1 ~]# mysql -p
    =============================================================
    Enter password: 
    Welcome to the MySQL monitor.  Commands end with ; or \g.
    Your MySQL connection id is 2
    Server version: 5.7.24-log MySQL Community Server (GPL)
    
    Copyright (c) 2000, 2018, 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.
    
    mysql> grant all on *.* to root@'%' identified by 'Mahao+123';
    Query OK, 0 rows affected, 1 warning (0.00 sec)

\#再次检测