卸载宝塔面板：

1.wget http://download.bt.cn/install/bt-uninstall.sh

2.sh bt-uninstall.sh

命令：

cat /proc/version

Linux version 3.10.0-862.el7.x86_64 (builder@kbuilder.dev.centos.org) (gcc version 4.8.5 20150623 (Red Hat 4.8.5-28) (GCC) ) #1 SMP Fri Apr 20 16:44:24 UTC 2018

uname -a

Linux centos7-64-1 3.10.0-862.el7.x86_64 #1 SMP Fri Apr 20 16:44:24 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux

uname -r

3.10.0-862.el7.x86_64

getconf LONG_BIT

64

cat /etc/redhat-release

CentOS Linux release 7.5.1804 (Core)

rpm -qa | grep mariadb

mariadb-libs-5.5.60-1.el7_5.x86_64

rpm -qa | grep mysql 无结果

正式进入安装 mysql 步骤

1.wget http://repo.mysql.com/mysql-community-release-el7-5.noarch.rpm

目录多个mysql-community-release-el7-5.noarch.rpm

执行rpm -ivh mysql-community-release-el7-5.noarch.rpm

2.cd /etc/yum.repos.d/

多两个文件 mysql-community.repo和mysql-community-source.repo

3.安装 yum install mysql-server

4.启动 service mysqld start

5.查看状态 systemctl status mysqld 或者 service mysqld status

显示：Active: active (running) since 一 2019-07-22 09:33:13 CST; 1h 9min ago

卸载安装的 mysql

在下载官网的mysql57-community-release-el7-10.noarch.rpm，执行rpm -ivh的时候报依赖检测失败：

mysql-community-release 与 mysql57-community-release-el7-10.noarch 冲突。

命令查看mysql安装情况：rpm -qa | grep -i mysql

结果：

mysql-community-common-5.7.27-1.el7.x86_64

mysql-community-server-5.7.27-1.el7.x86_64

mysql-community-libs-5.7.27-1.el7.x86_64

mysql-community-release-el7-5.noarch

mysql-community-libs-compat-5.7.27-1.el7.x86_64

mysql-community-client-5.7.27-1.el7.x86_64

停止 mysql: service mysqld stop

删除命令:rpm -e 文件名

再find / -name mysql删除查找到的结果。

再删除配置文件 rm -rf /etc/my.cnf

mysql 初始密码的设置：

先查看临时密码，使用命令 vi /var/log/mysqld.log ，查找到A temporary password is generated for root@localhost: 8dR!2VlJTyaq。

mysql -u root -p 得到结果 ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/var/lib/mysql/mysql.sock' (2)

猜测应该是没有开启 mysql 的原因。启动 mysql 后，使用临时密码登录成功。

用该密码登录到服务端后，必须马上修改密码，不然会报如下错误：

mysql>select@@log_error;

ERROR1820(HY000): You must reset your password using ALTER USER statement before executing this statement.

mysql>

修改密码

ALTER USER 'root'@'localhost' IDENTIFIED BY '***';
密码的要求是大写加小写加数字且大于8位。
这样密码就修改成功了。

授权其他机器登录

mysql> GRANT ALL PRIVILEGES ON *.* TO 'root'@'%' IDENTIFIED BY '***' WITH GRANT OPTION;
Query OK, 0 rows affected, 1 warning (0.00 sec)

mysql> FLUSH  PRIVILEGES;
Query OK, 0 rows affected (0.00 sec)

mysql> 

然而其他机器登录还是报错：2003 - Can't connect to MySQL server on '192.168.1.79' (61 "Connection refused")
原因是因为防火墙没有开启。
firewall-cmd --state
firewall-cmd --list-all
firewall-cmd --add-port=3306/tcp --permanent
firewall-cmd --reload