MHA（Master High Availability）是MySQL高可用性环境下的成熟解决方案，由youshimaton开发，适用于故障切换和主从提升。MHA由Manager和Node两部分组成，能自动完成数据库故障切换，保证数据一致性，支持一主多从架构。
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:
mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| mysql |
| performance_schema |
| sys |
| test |
+--------------------+
5 rows in set (0.01 sec)
mysql> drop database test
-> ;
Query OK, 1 row affected (0.02 sec)
mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| mysql |
| performance_schema |
| sys |
+--------------------+
4 rows in set (0.00 sec)
mysql> CREATE DATABASE taylor;
Query OK, 1 row affected (0.00 sec)
mysql> use taylor;
Database changed
mysql> create table usertb (
-> username varchar(10) not null,
-> password varchar(15) not null);
Query OK, 0 rows affected (0.02 sec)
mysql> desc usertb;
+----------+-------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+----------+-------------+------+-----+---------+-------+
| username | varchar(10) | NO | | NULL | |
| password | varchar(15) | NO | | NULL | |
+----------+-------------+------+-----+---------+-------+
2 rows in set (0.00 sec)
mysql> insert into usertb values ('user1','123');
Query OK, 1 row affected (0.00 sec)
mysql> select * from usertb;
+----------+----------+
| username | password |
+----------+----------+
| user1 | 123 |
+----------+----------+
1 row in set (0.00 sec)
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
扫一扫
916
被折叠的 条评论
为什么被折叠?
到【灌水乐园】发言
