常见问题
MySQL密码正确但无法登录的情况
这种情况一般都是因为缓存，使用mysql -u root -p123456直到成功登陆为止，并且进入之后重新修改密码，多次重复修改密码的命令并且再一次清除缓存后退出。
ALTER USER 'root'@'localhost' IDENTIFIED WITH mysql_native_password BY '123456';
flush privileges;
MySQL安装的GPG密钥问题
前言
在MySQL安装的过程中，我们出现了不能通过YUM安装的MySQL的问题，YUM工具警告说安装包的GPG密钥无效或未安装，这意味着不能验证该包的真实性和完整性。系统尝试从指定的本地路径检索密钥，但没有找到有效的密钥与包匹配。
具体错误
Downloading packages:
warning: /var/cache/yum/x86_64/7/mysql80-community/packages/mysql-community-client-8.0.36-1.el7.x86_64.rpm: Header V4 RSA/SHA256 Signature, key ID a8d3785c: NOKEY
Retrieving key from file:///etc/pki/rpm-gpg/RPM-GPG-KEY-mysql
The GPG keys listed for the "MySQL 8.0 Community Server" repository are already installed but they are not correct for this package.
Check that the correct key URLs are configured for this repository.
Failing package is: mysql-community-client-8.0.36-1.el7.x86_64
GPG Keys are configured as: file:///etc/pki/rpm-gpg/RPM-GPG-KEY-mysql
解决方式
yum install net-tools -y # 检查和安装网络工具包
yum list installed | grep mysql # 检查已安装的MySQL安装包
rpm -e --nodeps mysql80-community-release-el7-8.noarch # 强制删除指定的MySQL仓库包，不检查依赖。
rm -rf /etc/my.cnf # 删除MySQL的主配置文件。
rpm --import https://repo.mysql.com/RPM-GPG-KEY-mysql-2022 # 导入MySQL的GPG公钥，用于验证软件包。
rpm -Uvh https://dev.mysql.com/get/mysql80-community-release-el7-2.noarch.rpm# 安装新的MySQL仓库配置包。
yum -y install mysql-community-server# 安装MySQL服务器及其依赖。
此处出现了GPG的错误，我们需要通过绕过GPG的检查来实现安装
yum -y install mysql-community-server --nogpgcheck # 忽略GPG密钥检查，重新安装
systemctl start mysqld && systemctl enable mysqld # 启动MySQL服务并设置为开机启动。
systemctl status mysqld # 检查MySQL服务状态，确认服务已经运行
grep 'temporary password' /var/log/mysqld.log # 获取随机密码并登录
ALTER USER 'root'@'localhost' IDENTIFIED WITH mysql_native_password BY '123456';
set global validate_password.policy=0;
ALTER USER USER() IDENTIFIED BY 'wingkin45@A.';
set global validate_password.policy=0;
set global validate_password.length=4;
ALTER USER 'root'@'%' IDENTIFIED WITH mysql_native_password BY '123456';
flush privileges;
MySQL自动化安装脚本
echo "INFO : BEGIN INSTALLING MYSQL8 ..."
#检查mysql服务版本，若存在Mysql8,直接退出
me=`ps -ef|grep mysqld|wc -l`
if [ $me -eq 2 ];then
me=`systemctl status mysqld|grep Docs|awk -F: '{print $NF}'`
if [ $? -eq 0 -a "$me" == "mysql(8)" ];then
echo "INFO : MYSQL8 FOUND "
exit 0
fi
#若存在旧版本的mysql,且服务处于启动状态
systemctl status mysqld|grep "active (running)"
if [ $? -eq 0 ];then
systemctl stop mysqld
echo "INFO : OLD MYSQL SERVICE FOUND BUT STOPPED"
fi
fi
#若存在旧版本的残留，则直接卸载
names=`rpm -qa|grep mysql`
for name in $names;do
yum -y remove $name 1>/dev/null 2>&1
echo "INFO : OLD MYSQL RESOURCE [ $name ] FOUND AND REMOVED"
done
#rpm 安装mysql8
src=$1
if [[ ! -e $src || ! -f $src ]];then
echo "ERROR : PLEASE PROVIDE MYSQL8 RPM FILE "
exit 1
fi
if [[ ! "$src" =~ mysql8.*\.rpm$ ]];then
echo "ERROR : RPM PACKAGE OR NOT MYSQL8"
exit 1
fi
rpm -ivh $src 1>/dev/null 2>&1
if [ $? -eq 0 ];then
echo "INFO : SUCCESS TO RPM INSTALL MYSQL8"
else
echo "ERROR : FAIL TO RPM INSTALL MYSQL8"
exit 2
fi
# yum 安装mysql8服务
yum -y install mysql-community-server --nogpgcheck 1>/dev/null 2>&1
if [ $? -eq 0 ];then
echo "INFO : SUCCESS TO YUM MYSQL8 SERVICE"
else
echo "ERROR : FAIL TO YUM MYSQL8 SERVICE"
exit 3
fi
#检查服务是否已启动,若未启动则启动
me=`systemctl status mysqld|grep "active (running)"`
if [ $? -ne 0 ];then
systemctl start mysqld
fi
echo "INFO : MYSQL8 SERVICE STARTED"
echo "INFO : FINISH INSTALL MYSQL8"
unset me
unset names
unset src
