清除自带的mariadb
> rpm -qa|grep mariadb
mariadb-libs-5.5.44-2.el7.centos.x86_64
> rpm -e --nodeps mariadb-libs-5.5.44-2.el7.centos.x86_64
下载并解压缩 mysql-8.0.16-2.el7.x86_64.rpm-bundle.tar
> tar zvf mysql-8.0.16-2.el7.x86_64.rpm-bundle.tar
> ls -l
-rw-r--r--. 1 root root 607068160 6月 24 10:12 mysql-8.0.16-2.el7.x86_64.rpm-bundle.tar
-rw-r--r--. 1 7155 31415 33432660 5月 3 12:38 mysql-community-client-8.0.16-2.el7.x86_64.rpm
-rw-r--r--. 1 7155 31415 588520 5月 3 12:38 mysql-community-common-8.0.16-2.el7.x86_64.rpm
-rw-r--r--. 1 7155 31415 5712552 5月 3 12:38 mysql-community-devel-8.0.16-2.el7.x86_64.rpm
-rw-r--r--. 1 7155 31415 24493344 5月 3 12:38 mysql-community-embedded-compat-8.0.16-2.el7.x86_64.rpm
-rw-r--r--. 1 7155 31415 3127296 5月 3 12:38 mysql-community-libs-8.0.16-2.el7.x86_64.rpm
-rw-r--r--. 1 7155 31415 2177156 5月 3 12:38 mysql-community-libs-compat-8.0.16-2.el7.x86_64.rpm
-rw-r--r--. 1 7155 31415 422672748 5月 3 12:39 mysql-community-server-8.0.16-2.el7.x86_64.rpm
-rw-r--r--. 1 7155 31415 114848996 5月 3 12:40 mysql-community-test-8.0.16-2.el7.x86_64.rpm
开始依次安装：
> rpm -ivh mysql-community-common-8.0.16-2.el7.x86_64.rpm
> rpm -ivh mysql-community-libs-8.0.16-2.el7.x86_64.rpm
> rpm -ivh mysql-community-devel-8.0.16-2.el7.x86_64.rpm
> rpm -ivh mysql-community-client-8.0.16-2.el7.x86_64.rpm
> rpm -ivh mysql-community-server-8.0.16-2.el7.x86_64.rpm
如果提示依赖其它一些包，根据提示，挨个安装就行了。例如：
warning: mysql-community-server-8.0.16-2.el7.x86_64.rpm: Header V3 DSA/SHA1 Signature, key ID 5072e1f5: NOKEY
error: Failed dependencies:
/usr/bin/perl is needed by mysql-community-server-8.0.16-2.el7.x86_64
net-tools is needed by mysql-community-server-8.0.16-2.el7.x86_64
perl(Getopt::Long) is needed by mysql-community-server-8.0.16-2.el7.x86_64
perl(strict) is needed by mysql-community-server-8.0.16-2.el7.x86_64
不重要的警告可以忽略，强制安装： --nodeps --force
启动mysql
> service mysqld start
Redirecting to /bin/systemctl start mysqld.service
修改默认的root密码。
可以在日志文件中找到初始密码：
> grep 'temporary password' /var/log/mysqld.log
2019-06-24T02:32:21.735405Z 5 [Note] [MY-010454] [Server] A temporary password is generated for root@localhost: ts?7L9#reubW
登录mysql
mysql -h127.0.0.1 -uroot -pts?7L9#reubW
mysql: [Warning] Using a password on the command line interface can be insecure.
Welcome to the MySQL monitor. Commands end with ; or g.
Your MySQL connection id is 10
Server version: 8.0.16
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>
修改root密码：
mysql> ALTER USER 'root'@'localhost' IDENTIFIED BY 'xxxxxx';
mysql> GRANT ALL PRIVILEGES ON *.* TO 'root'@'%' IDENTIFIED BY 'xxxxxx' WITH GRANT OPTION;FLUSH PRIVILEGES;
允许从其它主机访问：
mysql> update mysql.user set host='%' where user ='root';
修改密码规则：
mysql> update mysql.user set plugin='mysql_native_password', authentication_string='' where user='root';
mysql> ALTER USER 'root'@'%' IDENTIFIED WITH mysql_native_password BY 'xxxxxx';
修改配置文件：/etc/my.conf
[mysqld]
datadir=/data/mysql
socket=/var/lib/mysql/mysql.sock
log-error=/var/log/mysqld.log
pid-file=/var/run/mysqld/mysqld.pid
character-set-server=utf8
default-time-zone='+08:00'
wait_timeout=31536000
interactive_timeout=31536000
max_connections=4000
[mysql]
default-character-set=utf8
重启服务
> service mysqld restart