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Centos8卸载与安装MySQL5.7(呕心沥血版)

前言 :最近自己的服务器重装了系统,上面的软件都没了,重装了MySQL5.7,但是遇到了许多问题,要么就是下载的是MySQL8.0要么就是mysql-community-server下载失败,经过几个小时的google终于安装上了,并且能够在本机的navicat(sqlyog)能够访问到服务器上的数据库。于是写了这篇详细的文档,给以后的自己以及遇到相同问题的朋友一个好的参考方案。

1. 卸载MySQL

安装之前先把服务器上关于MySQL的资源全部卸载,防止遇到不知名的错误(此方法同样适用于想卸载MySQL的)

  • 1.1 yum方式查询是否安装了MySQL

    yum list installed mysql*
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    如果出现:

    Dependencies resolved.
    ===============================================================================================================================================================================================
     Package                                              Architecture                         Version                                       Repository                                       Size
    ===============================================================================================================================================================================================
    Installing:
     mysql-community-server                               x86_64                               5.7.29-1.el7                                  mysql57-community                               175 M
    Installing dependencies:
     mysql-community-client                               x86_64                               5.7.29-1.el7                                  mysql57-community                                26 M
     mysql-community-common                               x86_64                               5.7.29-1.el7                                  mysql57-community                               311 k
     mysql-community-libs                                 x86_64                               5.7.29-1.el7                                  mysql57-community                               2.5 M
    
    Transaction Summary
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    说明有,需要卸载。

  • 1.2 yum方式卸载(如果有,则执行这一步)

    1. yum remove mysql-community-server mysql-community-client mysql-community-common mysql-community-libs
    2. rm -rf /var/lib/mysql
    3. rm /etc/my.cnf 
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  • 1.3 rpm查看是否安装mysql

    rpm -qa | grep -i mysql  
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    如果出现

    mysql-community-client-5.7.27-1.el6.x86_64
    mysql-community-common-5.7.29-1.el7.x86_64
    mysql-community-server-5.7.29-1.el7.x86_64
    mysql-community-libs-5.7.27-1.el6.x86_64
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    则说明存在

  • 1.4 rpm卸载MySQL

    rpm -e mysql-community-client-5.7.27-1.el6.x86_64
    rpm -e mysql-community-common-5.7.29-1.el7.x86_64
    rpm -emysql-community-server-5.7.29-1.el7.x86_64
    rpm -e mysql-community-libs-5.7.27-1.el6.x86_64
    cd /var/lib/  
    rm -rf mysql/
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  • 1.5 清除剩余资源文件:

    whereis mysql
    出现:mysql: /usr/bin/mysql /usr/lib64/mysql /usr/share/mysql /usr/share/man/man1/mysql.1.gz
    删除:rm -rf "上面的资源文件(如:/usr/bin/mysql)"
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  • 1.6 删除MySQL残留的配置文件

    rm –rf /usr/my.cnf
    rm -rf /root/.mysql_sercret
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  • 1.7 再次检查是否完全删除

    chkconfig --list | grep -i mysql
    chkconfig --del mysqld
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    如果还有资源没有删除干净,重复以上方法

2. 安装MySQL

  • 2.1 添加MySQL存储库

    • 禁用MySQL默认的AppStream存储库:

      sudo dnf remove @mysql
      sudo dnf module reset mysql && sudo dnf module disable mysql
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    • centos8没有MySQL存储库,因此我们将使用centos 7存储库。创建一个新的存储库文件。

      sudo vim /etc/yum.repos.d/mysql-community.repo
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    • 将以下数据插入上面的存储库中

      [mysql57-community]
      name=MySQL 5.7 Community Server
      baseurl=http://repo.mysql.com/yum/mysql-5.7-community/el/7/$basearch/
      enabled=1
      gpgcheck=0
      
      [mysql-connectors-community]
      name=MySQL Connectors Community
      baseurl=http://repo.mysql.com/yum/mysql-connectors-community/el/7/$basearch/
      enabled=1
      gpgcheck=0
      
      [mysql-tools-community]
      name=MySQL Tools Community
      baseurl=http://repo.mysql.com/yum/mysql-tools-community/el/7/$basearch/
      enabled=1
      gpgcheck=0
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  • 2.2 安装MySQL(这里我选择MySQL5.7)

    sudo dnf --enablerepo=mysql57-community install mysql-community-server
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  • 2.2.1 如果安装失败,使用以下方法进行安装

    • 先下载rpm包
    wget https://dev.mysql.com/get/Downloads/MySQL-5.7/mysql-community-common-5.7.27-1.el6.x86_64.rpm
    wget https://dev.mysql.com/get/Downloads/MySQL-5.7/mysql-community-libs-5.7.27-1.el6.x86_64.rpm
    wget https://dev.mysql.com/get/Downloads/MySQL-5.7/mysql-community-client-5.7.27-1.el6.x86_64.rpm
    wget https://dev.mysql.com/get/Downloads/MySQL-5.7/mysql-community-server-5.7.27-1.el6.x86_64.rpm
    复制代码
    • 再安装
    yum install -y mysql-community-common-5.7.27-1.el6.x86_64.rpm
    yum install -y mysql-community-libs-5.7.27-1.el6.x86_64.rpm
    yum install -y mysql-community-client-5.7.27-1.el6.x86_64.rpm
    yum install -y mysql-community-server-5.7.27-1.el6.x86_64.rpm 
    复制代码
  • 2.3 下载完成后检查版本

 [root@aliyun-zuojun ~]# rpm -qi mysql-community-server 
 Name        : mysql-community-server
 Version     : 5.7.29
 Release     : 1.el7
 Architecture: x86_64
 Install Date: Sat 22 Feb 2020 11:04:07 AM CST
 Group       : Applications/Databases
 Size        : 801919839
 License     : Copyright (c) 2000, 2019, Oracle and/or its affiliates. All rights reserved. Under GPLv2 license as shown in the Description field.
 Signature   : DSA/SHA1, Thu 19 Dec 2019 04:12:40 PM CST, Key ID 8c718d3b5072e1f5
 Source RPM  : mysql-community-5.7.29-1.el7.src.rpm
 Build Date  : Wed 18 Dec 2019 09:31:48 PM CST
 Build Host  : loki02.no.oracle.com
 Relocations : (not relocatable)
 Packager    : MySQL Release Engineering <mysql-build@oss.oracle.com>
 Vendor      : Oracle and/or its affiliates
 URL         : http://www.mysql.com/
 Summary     : A very fast and reliable SQL database server
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出现以上信息说明安装成功

  • 2.4 检查 mysql 源是否安装成功

    yum repolist enabled | grep "mysql.*-community.*"
    出现以下信息说明安装成功:
    mysql-connectors-community MySQL Connectors Community                       141
    mysql-tools-community      MySQL Tools Community                            105
    mysql57-community          MySQL 5.7 Community Server
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  • 2.5 启动MySQL

     systemctl start mysqld
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  • 2.6 查看启动状态

    systemctl status mysqld
    // 出现以下信息,则启动成功
     Loaded: loaded (/usr/lib/systemd/system/mysqld.service; enabled; vendor preset: disabled)
       Active: active (running) since Sat 2020-02-22 11:14:47 CST; 2h 19min ago
         Docs: man:mysqld(8)
               http://dev.mysql.com/doc/refman/en/using-systemd.html
      Process: 21345 ExecStart=/usr/sbin/mysqld --daemonize --pid-file=/var/run/mysqld/mysqld.pid $MYSQLD_OPTS (code=exited, status=0/SUCCESS)
      Process: 21323 ExecStartPre=/usr/bin/mysqld_pre_systemd (code=exited, status=0/SUCCESS)
     Main PID: 21349 (mysqld)
        Tasks: 30 (limit: 11516)
       Memory: 209.1M
       CGroup: /system.slice/mysqld.service
               ?..21349 /usr/sbin/mysqld --daemonize --pid-file=/var/run/mysqld/mysqld.pid
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  • 2.7 设置开机启动

    systemctl enable mysqld
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  • 2.8 刷新所有修改过的配置文件

    systemctl daemon-reload
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  • 2.9 获取安装mysql后生成的临时密码,用于登录

    grep 'temporary password' /var/log/mysqld.log
    # 如果出现如下列信息,密码为: BL=azx(1u;Br
    2020-02-22T03:05:17.741049Z 1 [Note] A temporary password is generated for root@localhost: BL=azx(1u;Br
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  • 2.10 登录MySQL

    mysql -uroot -p
    # 再输入上面查找得到的临时密码即可进入mysql
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  • 2.11 修改登录密码

    mysql> ALTER USER 'root'@'localhost' IDENTIFIED BY 'MyNewPass4!(修改后的密码,注意必须包含大小写字母数字以及特殊字符并且长度不能少于8位,否则会报错)';
    或者通过:mysql> set password for 'root'@'localhost'=password('MyNewPass4!');
    或者通过:mysql> use mysql;
            mysql> update user set password=PASSWORD('MyNewPass5!') where user='root';
            mysql> flush privileges;
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  • 2.12 添加远程登录用户(即本机访问服务器上的MySQL)

    mysql> GRANT ALL PRIVILEGES ON *.* TO 'zhangsan(用户名)'@'%' IDENTIFIED BY 'Zhangsan2018!(密码)' WITH GRANT OPTION;
    # 或者直接将root权限修改为可以通过远程访问(但不推荐)
    mysql> use mysql;
    mysql> UPDATE user SET Host='%' WHERE User='root';
    mysql> flush privileges;
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  • 2.13 设置默认编码为utf-8(mysql安装后默认不支持中文)

    vim /etc/my.cnf
    # 进入文件后添加下面的配置即可
    [mysqld]
    character-set-server=utf8
    [client]
    default-character-set=utf8
    [mysql]
    default-character-set=utf8
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  • 2.14 重启MySQL服务并进入MySQL

    shell> systemctl restart mysqld
    shell> mysql -uroot -p
    mysql> show variables like 'character%';
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    • 出现如下则说明编码修改完成
    +--------------------------+----------------------------+
    | Variable_name            | Value                      |
    +--------------------------+----------------------------+
    | character_set_client     | utf8                       |
    | character_set_connection | utf8                       |
    | character_set_database   | utf8                       |
    | character_set_filesystem | binary                     |
    | character_set_results    | utf8                       |
    | character_set_server     | utf8                       |
    | character_set_system     | utf8                       |
    | character_sets_dir       | /usr/share/mysql/charsets/ |
    +--------------------------+----------------------------+
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    • 退出MySQL
    mysql> quit
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  • 使用本机电脑navicat/sqlyog等一系列客户端工具连接服务器上的mysql,用户名和密码为远程用户的用户名和密码,如果是将root权限修改为可以远程访问,就用root访问。

以上就是全部对mysql的安装与卸载的教程,希望对你有帮助。

可以参考mysql官网文档:dev.mysql.com/doc/refman/…

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