MySQL 5.7多實例安裝配置

1. 背景描述

a. MySQL多實例概念

簡單的說，就是在一臺服務器上面開啓多個不同的服務端口（如：3306,3307），運行多個MySQL服務進程，這些服務通過不同的socket監聽不同的服務端口來提供各自的服務。

b. MySQL多實例作用與問題

• 有效利用服務器資源
  資源有剩餘時，可充分利用剩餘的資源提供服務；
• 節約服務器資源
  當公司資金緊張，但是服務器又需要各自盡量獨立提供服務；而且，需要主從同步技術時，多實例就再好不過了；
• 資源互相搶佔問題
  當某個服務併發很高或者有慢查詢時，整個實例會消耗更多的內存，CPU，磁盤IO資源，導致服務器上其它實例提供服務的質量下降；

c. MySQL多實例應用場景

• 資金緊張的公司
• 併發訪問不是特別大的業務
• 門戶網站應用MySQL多實例場景

2. 環境準備

a. 操作系統：CentOS Linux release 7.6.1810
b. MySQL：mysql-5.7.27.tar.gz，點擊下載，準備MySQL的源碼編譯包
c. boost：boost_1_59_0.tar.gz，點擊下載，安裝MySQL 5.7的時候，需要依賴boost庫，MySQL5.7對應的boost版本是1.59
d. cmake：cmake-2.8.12.2.tar.gz，點擊下載，編譯安裝MySQL時，使用cmake的方式進行編譯安裝，因此，需要先安裝cmake

3. 安裝方法

3.1 編譯安裝cmake

#建議創建個tools目錄，將所有的軟件包放在一起

[root@192168066012_MySQL_5_7_27 ~]# mkdir -p /home/tools/
[root@192168066012_MySQL_5_7_27 ~]# cd /home/tools/
[root@192168066012_MySQL_5_7_27 tools]# ls -l
total 143932
-rw-r--r--  1 root root 83709983 Jul 31 18:34 boost_1_59_0.tar.gz
-rw-r--r--  1 root root  6068231 Jul 31 18:36 cmake-2.8.12.2.tar.gz
-rw-r--r--  1 root root 54398696 Jul 31 18:34 mysql-5.7.27.tar.gz

#解壓cmake安裝包

[root@192168066012_MySQL_5_7_27 tools]# tar xf cmake-2.8.12.2.tar.gz
[root@192168066012_MySQL_5_7_27 tools]# cd cmake-2.8.12.2
[root@192168066012_MySQL_5_7_27 cmake-2.8.12.2]# ll
total 3056
-rwxr-xr-x   1  501 games   53974 Jan 17  2014 bootstrap
-rw-r--r--   1  501 games  254736 Jan 17  2014 ChangeLog.manual
-rw-r--r--   1  501 games 2603523 Jan 17  2014 ChangeLog.txt
-rw-r--r--   1  501 games    5465 Jan 17  2014 CMakeCPack.cmake
-rw-r--r--   1  501 games    3436 Jan 17  2014 CMakeCPackOptions.cmake.in
-rw-r--r--   1  501 games     153 Jan 17  2014 CMakeGraphVizOptions.cmake
-rw-r--r--   1  501 games   25439 Jan 17  2014 CMakeLists.txt
-rw-r--r--   1  501 games    4481 Jan 17  2014 CMakeLogo.gif
-rw-r--r--   1  501 games     796 Jan 17  2014 cmake_uninstall.cmake.in
-rw-r--r--   1  501 games    2515 Jan 17  2014 CompileFlags.cmake
-rwxr-xr-x   1  501 games      99 Jan 17  2014 configure
-rw-r--r--   1  501 games    2637 Jan 17  2014 Copyright.txt
-rw-r--r--   1  501 games    1050 Jan 17  2014 CTestConfig.cmake
-rw-r--r--   1  501 games    3338 Jan 17  2014 CTestCustom.cmake.in
-rw-r--r--   1  501 games     145 Jan 17  2014 CTestCustom.ctest.in
-rw-r--r--   1  501 games     809 Jan 17  2014 DartConfig.cmake
-rw-r--r--   1  501 games    4144 Jan 17  2014 DartLocal.conf.in
drwxr-xr-x   3 root root      142 Aug  1 14:32 Docs
-rw-r--r--   1  501 games   28046 Jan 17  2014 doxygen.config
drwxr-xr-x   4 root root       53 Aug  1 14:32 Example
drwxr-xr-x   9 root root    16384 Aug  1 14:32 Modules
-rw-r--r--   1  501 games    1946 Jan 17  2014 Readme.txt
drwxr-xr-x   7 root root    24576 Aug  1 14:32 Source
drwxr-xr-x   2 root root     4096 Aug  1 14:32 Templates
drwxr-xr-x 169 root root     8192 Aug  1 14:32 Tests
drwxr-xr-x  15 root root     4096 Aug  1 14:32 Utilities

#開始編譯安裝

[root@192168066012_MySQL_5_7_27 cmake-2.8.12.2]# ./configure
...省略
CMake has bootstrapped.  Now run gmake.

#看到“Now run gmake”說明ok，可以進行gmake && gmake install

[root@192168066012_MySQL_5_7_27 cmake-2.8.12.2]# gmake
...省略
[100%] Built target pseudonl_valgrind
[root@192168066012_MySQL_5_7_27 cmake-2.8.12.2]# gmake install
...省略
-- Installing: /usr/local/share/cmake-2.8/completions/ctest

提示：
每一步結束後，可以使用echo $? ，當返回值爲0時，說明編譯過程正常

3.2 將boost庫解壓到/usr/local/目錄

#指定解壓到/usr/local/目錄，使用 -C 參數

[root@192168066012_MySQL_5_7_27 tools]# tar xf boost_1_59_0.tar.gz -C /usr/local/
[root@192168066012_MySQL_5_7_27 tools]# cd /usr/local/
[root@192168066012_MySQL_5_7_27 local]# mv boost_1_59_0/ boost
[root@192168066012_MySQL_5_7_27 local]# ls -l
total 0
drwxr-xr-x. 2 root root   45 Jul 30 19:49 bin
drwx------  8  501 games 302 Aug 12  2015 boost
drwxr-xr-x  3 root root   23 Jul 30 19:49 doc
drwxr-xr-x. 2 root root    6 Apr 11  2018 etc
drwxr-xr-x. 2 root root    6 Apr 11  2018 games
drwxr-xr-x. 2 root root    6 Apr 11  2018 include
drwxr-xr-x. 2 root root    6 Apr 11  2018 lib
drwxr-xr-x. 2 root root    6 Apr 11  2018 lib64
drwxr-xr-x. 2 root root    6 Apr 11  2018 libexec
drwxr-xr-x  3 root root   18 Jul 30 19:49 man
drwxr-xr-x. 2 root root    6 Apr 11  2018 sbin
drwxr-xr-x. 7 root root   81 Jul 30 19:49 share
drwxr-xr-x. 2 root root    6 Apr 11  2018 src

3.3 解壓MySQL 5.7，並進行編譯安裝

3.3.1 安裝MySQL 5.7的依賴包

[root@192168066012_MySQL_5_7_27 tools]# yum install ncurses-devel -y
...省略
Installed:
    ncurses-devel.x86_64 0:5.9-14.20130511.el7_4

Complete!
[root@192168066012_MySQL_5_7_27 tools]# yum install libaio-devel -y
...省略
Installed:
  libaio-devel.x86_64 0:0.3.109-13.el7

Dependency Installed:
  libaio.x86_64 0:0.3.109-13.el7

Complete!

提示：
MySQL 5.7依賴的軟件包：gcc gcc-c++ ncurses ncurses-devel bison make等供參考，安裝前可以使用rpm -qa|grep ${軟件包名稱}檢查一下

3.3.2 創建MySQL文件存放目錄，用戶和組

#創建MySQL多實例的相關文件目錄

[root@192168066012_MySQL_5_7_27 tools]# mkdir -p /application/mysql
[root@192168066012_MySQL_5_7_27 tools]# mkdir -p /application/mysql/logs
[root@192168066012_MySQL_5_7_27 tools]# mkdir -p /application/mysql/data/{3306,3307}/data
[root@192168066012_MySQL_5_7_27 tools]# tree -L 3 /application/mysql/data/
/application/mysql/data/
|-- 3306
|   `-- data
`-- 3307
    `-- data

4 directories, 0 files

#創建mysql組和用戶

[root@192168066012_MySQL_5_7_27 tools]# groupadd mysql
[root@192168066012_MySQL_5_7_27 tools]# useradd mysql -s /sbin/nologin -M -g mysql
[root@192168066012_MySQL_5_7_27 tools]# id mysql
uid=1000(mysql) gid=1000(mysql) groups=1000(mysql)

說明：
-s /sbin/nologin 用戶不能登錄系統
-M 不創建用戶的HOME目錄
-g 指定用戶登錄組的GID或組名

3.3.3 編譯安裝MySQL 5.7

#解壓源碼mysql-5.7.27.tar.gz安裝包

[root@192168066012_MySQL_5_7_27 tools]# cd /home/tools/
[root@192168066012_MySQL_5_7_27 tools]# tar xf mysql-5.7.27.tar.gz

#cmake配置編譯參數

[root@192168066012_MySQL_5_7_27 tools]# cd mysql-5.7.27
[root@192168066012_MySQL_5_7_27 mysql-5.7.27]# cmake . -DCMAKE_INSTALL_PREFIX=/application/mysql \
 -DMYSQL_DATADIR=/application/mysql/data \
 -DMYSQL_UNIX_ADDR=/application/mysql/tmp/mysql.sock \
 -DDEFAULT_CHARSET=utf8 \
 -DDEFAULT_COLLATION=utf8_general_ci \
 -DEXTRA_CHARSETS=gbk,gb2312,utf8,ascii \
 -DENABLED_LOCAL_INFILE=ON \
 -DWITH_INNOBASE_STORAGE_ENGINE=1 \
 -DWITH_FEDERATED_STORAGE_ENGINE=1 \
 -DWITH_BLACKHOLE_STORAGE_ENGINE=1 \
 -DWITHOUT_EXAMPLE_STORAGE_ENGINE=1 \
 -DWITHOUT_PARTITION_STORAGE_ENGINE=1 \
 -DWITH_ZLIB=bundled \
 -DWITH_EMBEDDED_SERVER=1 \
 -DWITH_DEBUG=0 \
 -DWITH_BOOST=/usr/local/boost

#看到如下信息，說明cmake編譯完成，執行make繼續安裝

 -- Configuring done
 -- Generating done
 -- Build files have been written to: /home/tools/mysql-5.7.27

#繼續執行make install繼續安裝

...省略
 Linking CXX executable my_safe_process
 [100%] Built target my_safe_process

#安裝完成

...省略
 -- Installing: /application/mysql-5.7.27/share/aclocal/mysql.m4
 -- Installing: /application/mysql-5.7.27/support-files/mysql.server

提示：
如果上述操作未出現錯誤（每個步驟結束後，都可以使用echo $?看返回值是否爲0，爲0則表示正確），查看/application/mysql/目錄，若其下有內容，則表示MySQL5.7.27源代碼包採用cmake方式安裝成功了

3.4 配置MySQL系統環境變量

[root@192168066012_MySQL_5_7_27 ~]# echo 'export PATH=/application/mysql/bin:$PATH' >>/etc/profile
[root@192168066012_MySQL_5_7_27 ~]# tail -1 /etc/profile
export PATH=/application/mysql/bin:$PATH

#使/etc/profile配置文件立即生效

[root@192168066012_MySQL_5_7_27 ~]# source /etc/profile
[root@192168066012_MySQL_5_7_27 ~]# echo $PATH
/application/mysql/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/root/bin

3.5 初始化數據庫

3.5.1 配置my.cnf文件

#修改/etc/my.cnf文件，和5.6之前的版本不一樣，5.7版本support-files目錄下沒有.cnf文件，因此，需要自己手動編輯

[root@192168066012_MySQL_5_7_27 ~]# cp /etc/my.cnf /etc/my.cnf.bak
[root@192168066012_MySQL_5_7_27 ~]# vim /etc/my.cnf
[mysqld_multi]
mysqld = /application/mysql/bin/mysqld
mysqladmin = /application/mysql/bin/mysqladmin
log = /application/mysql/logs/mysql_multi.log

[mysqld1]
port = 3306
user = mysql
character_set_server = utf8
socket = /application/mysql/data/3306/mysql.sock
datadir = /application/mysql/data/3306/data
pid-file = /application/mysql/data/3306/mysql.pid
log-bin = /application/mysql/data/3306/mysql-bin
server-id = 1
log-error = /application/mysql/data/3306/mysql_boyu3306.err

[mysqld2]
port = 3307
user = mysql
character_set_server = utf8
socket = /application/mysql/data/3307/mysql.sock
datadir = /application/mysql/data/3307/data
pid-file = /application/mysql/data/3307/mysql.pid
log-bin = /application/mysql/data/3307/mysql-bin
server-id = 3
log-error = /application/mysql/data/3307/mysql_boyu3307.err

提示：
新增MySQL實例時，注意變更my.cnf配置文件及啓動腳本文件中的port和server-id，不要和已經運行的實例衝突；

3.5.2 修改my.cnf文件的屬主和屬組

[root@192168066012_MySQL_5_7_27 ~]# chown mysql:mysql /etc/my.cnf

3.5.3 更改MySQL安裝目錄的屬主和屬組

[root@192168066012_MySQL_5_7_27 ~]# chown -R mysql:mysql /application/mysql/

3.5.4 初始化數據庫

[root@192168066012_MySQL_5_7_27 data]# cd /application/mysql/
[root@192168066012_MySQL_5_7_27 mysql]# ./bin/mysqld --initialize-insecure --user=mysql --basedir=/application/mysql --datadir=/application/mysql/data/3306/data/
2019-08-07T03:33:57.693586Z 0 [Warning] TIMESTAMP with implicit DEFAULT value is deprecated. Please use --explicit_defaults_for_timestamp server option (see documentation for more details).
2019-08-07T03:33:57.973904Z 0 [Warning] InnoDB: New log files created, LSN=45790
2019-08-07T03:33:58.013774Z 0 [Warning] InnoDB: Creating foreign key constraint system tables.
2019-08-07T03:33:58.070602Z 0 [Warning] No existing UUID has been found, so we assume that this is the first time that this server has been started. Generating a new UUID: 30a49b8b-b8c4-11e9-b40d-000c290943d8.
2019-08-07T03:33:58.072487Z 0 [Warning] Gtid table is not ready to be used. Table 'mysql.gtid_executed' cannot be opened.
2019-08-07T03:33:58.074274Z 1 [Warning] root@localhost is created with an empty password ! Please consider switching off the --initialize-insecure option.
[root@192168066012_MySQL_5_7_27 mysql]# ./bin/mysqld --initialize-insecure --user=mysql --basedir=/application/mysql --datadir=/application/mysql/data/3307/data/
2019-08-07T03:34:06.558576Z 0 [Warning] TIMESTAMP with implicit DEFAULT value is deprecated. Please use --explicit_defaults_for_timestamp server option (see documentation for more details).
2019-08-07T03:34:06.792397Z 0 [Warning] InnoDB: New log files created, LSN=45790
2019-08-07T03:34:06.835971Z 0 [Warning] InnoDB: Creating foreign key constraint system tables.
2019-08-07T03:34:06.893802Z 0 [Warning] No existing UUID has been found, so we assume that this is the first time that this server has been started. Generating a new UUID: 35e6eba6-b8c4-11e9-b7dc-000c290943d8.
2019-08-07T03:34:06.896053Z 0 [Warning] Gtid table is not ready to be used. Table 'mysql.gtid_executed' cannot be opened.
2019-08-07T03:34:06.897815Z 1 [Warning] root@localhost is created with an empty password ! Please consider switching off the --initialize-insecure option.

提示：
初始化時，data目錄必須爲空目錄，否則初始化失敗，會報錯如下信息

2019-08-07T06:58:34.828541Z 0 [ERROR] --initialize specified but the data directory has files in it. Aborting.
2019-08-07T06:58:34.828576Z 0 [ERROR] Aborting

爲什麼要初始化數據庫？
a.初始化的主要目的是創建基礎的數據庫，例如：生成MySQL庫、表等
b.初始化後查看對應實例的數據目錄，可以看到如下信息

[root@192168066012_MySQL_5_7_27 mysql]# tree -L 3 /application/mysql/data/
/application/mysql/data/
|-- 3306
|   `-- data
|       |-- auto.cnf
|       |-- ib_buffer_pool
|       |-- ibdata1
|       |-- ib_logfile0
|       |-- ib_logfile1
|       |-- mysql
|       |-- performance_schema
|       `-- sys
`-- 3307
    `-- data
        |-- auto.cnf
        |-- ib_buffer_pool
        |-- ibdata1
        |-- ib_logfile0
        |-- ib_logfile1
        |-- mysql
        |-- performance_schema
        `-- sys

10 directories, 10 files

3.5.5 實例開啓SSL連接

[root@192168066012_MySQL_5_7_27 mysql]# /application/mysql/bin/mysql_ssl_rsa_setup --user=mysql --basedir=/application/mysql --datadir=/application/mysql/data/3306/data/
Generating a 2048 bit RSA private key
.....................+++
......+++
writing new private key to 'ca-key.pem'
-----
Generating a 2048 bit RSA private key
............+++
.................+++
writing new private key to 'server-key.pem'
-----
Generating a 2048 bit RSA private key
........................................................+++
...............................+++
writing new private key to 'client-key.pem'
-----
[root@192168066012_MySQL_5_7_27 mysql]# /application/mysql/bin/mysql_ssl_rsa_setup --user=mysql --basedir=/application/mysql --datadir=/application/mysql/data/3307/data/
Generating a 2048 bit RSA private key
..................................................................+++
..............................+++
writing new private key to 'ca-key.pem'
-----
Generating a 2048 bit RSA private key
.....+++
...............................................................+++
writing new private key to 'server-key.pem'
-----
Generating a 2048 bit RSA private key
.........+++
......+++
writing new private key to 'client-key.pem'
-----

3.5.6 修改data目錄下的server-key.pem文件權限

[root@192168066012_MySQL_5_7_27 ~]# cd /application/mysql/data/3306/data/
[root@192168066012_MySQL_5_7_27 data]# chmod +r server-key.pem
[root@192168066012_MySQL_5_7_27 data]# ls -lh server-key.pem
-rw-r--r-- 1 root root 1.7K Aug  7 15:07 server-key.pem
[root@192168066012_MySQL_5_7_27 data]# cd /application/mysql/data/3307/data/
[root@192168066012_MySQL_5_7_27 data]# chmod +r server-key.pem
[root@192168066012_MySQL_5_7_27 data]# ls -lh server-key.pem
-rw-r--r-- 1 root root 1.7K Aug  7 15:07 server-key.pem

提示：
如果不給文件server-key.pem其他用戶和組可讀權限的話，當啓動數據庫的時候，會報如下錯誤
2019-08-07T06:39:24.111526Z 0 [ERROR] SSL error: Unable to get private key from 'server-key.pem'
2019-08-07T06:39:24.111555Z 0 [Warning] Failed to set up SSL because of the following SSL library error: Unable to get private key

3.6 啓動MySQL數據庫

3.6.1 拷貝啓動腳本到/etc/init.d/目錄下，改名mysqld_multi，並賦予可執行權限

[root@192168066012_MySQL_5_7_27 ~]# cd /application/mysql
[root@192168066012_MySQL_5_7_27 mysql]# cp support-files/mysqld_multi.server /etc/init.d/mysqld_multi
[root@192168066012_MySQL_5_7_27 mysql]# chmod +x /etc/init.d/mysqld_multi
[root@192168066012_MySQL_5_7_27 mysql]# ll /etc/init.d/mysqld_multi
-rwxr-xr-x 1 root root 1061 8月   7 11:38 /etc/init.d/mysqld_multi

3.6.2 修改腳本中MySQL安裝目錄和bin目錄絕對路徑

[root@192168066012_MySQL_5_7_27 mysql]# diff /application/mysql/support-files/mysqld_multi.server /etc/init.d/mysqld_multi
17,18c17,18
< basedir=/usr/local/mysql
< bindir=/usr/local/mysql/bin
---
> basedir=/application/mysql
> bindir=/application/mysql/bin

提示：
如果MySQL不是安裝在/usr/local/目錄下，需要修改多實例mysqld_multi啓動腳本，將basedir=${MySQL安裝目錄}，bindir=${MySQL安裝目錄下的bin目錄}，否則執行啓動腳本會報“Can't execute /usr/local/mysql/bin/mysqld_multi from dir /usr/local/mysql”錯誤；

3.6.3 重新加載系統服務，將MySQL數據庫加入開機自啓動

[root@192168066012_MySQL_5_7_27 mysql]# /bin/systemctl daemon-reload
[root@192168066012_MySQL_5_7_27 mysql]# /bin/systemctl enable mysqld_multi
mysqld_multi.service is not a native service, redirecting to /sbin/chkconfig.
Executing /sbin/chkconfig mysqld_multi on
[root@192168066012_MySQL_5_7_27 mysql]# chkconfig --list

Note: This output shows SysV services only and does not include native
      systemd services. SysV configuration data might be overridden by native
      systemd configuration.

      If you want to list systemd services use 'systemctl list-unit-files'.
      To see services enabled on particular target use
      'systemctl list-dependencies [target]'.

mysqld_multi    0:off   1:off   2:on    3:on    4:on    5:on    6:off
netconsole      0:off   1:off   2:off   3:off   4:off   5:off   6:off
network         0:off   1:off   2:on    3:on    4:on    5:on    6:off

3.6.4 啓動MySQL數據庫，並檢查端口監聽狀態

[root@192168066012_MySQL_5_7_27 mysql]# /etc/init.d/mysqld_multi report
Reporting MySQL servers
MySQL server from group: mysqld1 is not running
MySQL server from group: mysqld2 is not running
[root@192168066012_MySQL_5_7_27 mysql]# /etc/init.d/mysqld_multi start
[root@192168066012_MySQL_5_7_27 mysql]# netstat -lntup
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address           Foreign Address         State       PID/Program name
tcp        0      0 0.0.0.0:22              0.0.0.0:*               LISTEN      6568/sshd
tcp        0      0 127.0.0.1:25            0.0.0.0:*               LISTEN      6814/master
tcp6       0      0 :::3306                 :::*                    LISTEN      7404/mysqld
tcp6       0      0 :::3307                 :::*                    LISTEN      7407/mysqld
tcp6       0      0 :::22                   :::*                    LISTEN      6568/sshd
tcp6       0      0 ::1:25                  :::*                    LISTEN      6814/master

3.7 連接MySQL數據庫

3.7.1 指定socket登陸3306數據庫

[root@192168066012_MySQL_5_7_27 mysql]# mysql -S /application/mysql/data/3306/mysql.sock
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 2
Server version: 5.7.27-log Source distribution

Copyright (c) 2000, 2019, 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> \q
Bye

3.7.2 指定socket登陸3307數據庫

[root@192168066012_MySQL_5_7_27 mysql]# mysql -S /application/mysql/data/3307/mysql.sock
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 2
Server version: 5.7.27-log Source distribution

Copyright (c) 2000, 2019, 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> \q
Bye

提示：
a. 本地登錄

• 多實例本地端登陸通過socket文件來指定登陸到哪個實例，此文件具體位置在mysql初始化時指定的，在本機登陸時登陸程序通過socket文件來判斷登陸的數據庫實例
• mysql.sock <== 文件是服務器與本地客戶端進行通信的Unix套接字文件
• 例如：mysql -S /application/mysql/data/3306/mysql.sock 登陸3306數據庫實例

b. 遠程登錄

• 遠程登錄指定多實例主機中的一個實例，TCP/IP端口（port）來指定所要登錄的mysql實例，此端口是在MySQL配置文件my.cnf中指定的。
• port <== 端口是一種“邏輯連接位置”，客戶端程序被分派計算機上特殊服務程序的一種方式
• 遠程登陸案例：
• grant all privileges on . to root@"192.168.66.11" identified by "boyu123"; #在MySQL服務端給客戶端192.168.66.11賦予所有的權限，包括遠程訪問權限
• flush privileges; #重新加載mysql授權表
• select user,host from mysql,user; #查看更改後的結果
• mysql -uroot -p'boyu123' -h 192.168.66.12 -P 3306 #在192.168.66.11上面執行此條命令，可以遠程登陸到數據庫

3.8 數據庫基本操作

3.8.1 修改多實例登陸密碼

[root@192168066012_MySQL_5_7_27 mysql]# mysqladmin -u root -p password "boyu123" -S /application/mysql/data/3306/mysql.sock
Enter password:
mysqladmin: [Warning] Using a password on the command line interface can be insecure.
Warning: Since password will be sent to server in plain text, use ssl connection to ensure password safety.
[root@192168066012_MySQL_5_7_27 mysql]# mysqladmin -u root -p password "boyu123" -S /application/mysql/data/3307/mysql.sock
Enter password:
mysqladmin: [Warning] Using a password on the command line interface can be insecure.
Warning: Since password will be sent to server in plain text, use ssl connection to ensure password safety.

3.8.2 優雅關閉多實例數據庫

#使用MySQL自帶的腳本

[root@192168066012_MySQL_5_7_27 mysql]# /etc/init.d/mysqld_multi stop
[root@192168066012_MySQL_5_7_27 mysql]# ps aux|grep mysqld
root      23962  0.0  0.0 112708   976 pts/0    S+   20:39   0:00 grep --color=auto mysqld

提示：此種方法會同時關閉服務器上面的所有數據庫，如果想一個一個關閉的話，可以使用mysqladmin方法

#使用mysqladmin的方法

[root@192168066012_MySQL_5_7_27 mysql]# mysqladmin -uroot -p"boyu123" -S /application/mysql/data/3307/mysql.sock shutdown
mysqladmin: [Warning] Using a password on the command line interface can be insecure.
[root@192168066012_MySQL_5_7_27 mysql]# ps aux|grep mysqld
mysql     24058  0.1 10.1 1181012 188944 pts/0  Sl   20:39   0:01 /application/mysql/bin/mysqld --port=3306 --user=mysql --character_set_server=utf8 --socket=/application/mysql/data/3306/mysql.sock --datadir=/application/mysql/data/3306/data --pid-file=/application/mysql/data/3306/mysql.pid --log-bin=/application/mysql/data/3306/mysql-bin --server-id=1 --log-error=/application/mysql/data/3306/mysql_boyu3306.err
root      28235  0.0  0.0 112708   976 pts/0    S+   20:51   0:00 grep --color=auto mysqld

3.9 MySQL 服務沒有起來，排查思路

a. 如果發現沒有顯示MySQL的端口，稍微等一會再看，MySQL服務啓動有些慢
b. 如果還不行，查看錯誤日誌，錯誤日誌路徑配置在my.cnf裏面
c. 仔細看所有命令返回的屏幕輸出，不要忽略關鍵的輸出內容
d. 如果是關聯服務，要同時查看相關服務的LOG