CentOS7 安装mysql数据库失败

我是跟着这个Linux入门教程_linux电子书 - 跟阿铭学linux(第2版)学习的，算是自学吧。自己Linux版本是CentOS 7 64位，然后在mysql官网下载的对应64位的5.7.21版本的mysql——mysql-5.7.21-linux-glibc2.12-x86_64.tar.gz，就是这个。安装完之后到启动那一步的时候出现了问题——我输入service mysqld start，然后是这样提示的——Starting MySQL... ERROR! The server quit without updating PID file (/data/mysql/localhost.localdomain.pid).。在网上找了一下午，也查看了/data/mysql/localhost.localdomain.err文档（好吧，其实我看不太明白）还是没什么进展，无法解决这个问题。这个文档截取部分如下：

2018-02-07T07:07:39.520069Z 0 [Note] InnoDB: Waiting for purge to start

2018-02-07T07:07:39.571116Z 0 [Note] InnoDB: 5.7.21 started; log sequence number 0

2018-02-07T07:07:39.574453Z 0 [Note] Plugin 'FEDERATED' is disabled.

mysqld: Table 'mysql.plugin' doesn't exist

2018-02-07T07:07:39.575779Z 0 [ERROR] Can't open the mysql.plugin table. Please run mysql_upgrade to create it.

2018-02-07T07:07:39.578308Z 0 [Note] Salting uuid generator variables, current_pid: 2664, server_start_time: 1517987258, bytes_sent: 0,

2018-02-07T07:07:39.578544Z 0 [Note] Generated uuid: '954ff69c-0bd5-11e8-8c4e-000c291213a2', server_start_time: 749849339475177506, bytes_sent: 76209120

2018-02-07T07:07:39.578594Z 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: 954ff69c-0bd5-11e8-8c4e-000c291213a2.

2018-02-07T07:07:39.581101Z 0 [Warning] Gtid table is not ready to be used. Table 'mysql.gtid_executed' cannot be opened.

2018-02-07T07:07:39.581335Z 0 [Warning] Failed to set up SSL because of the following SSL library error: SSL context is not usable without certificate and private key

2018-02-07T07:07:39.582252Z 0 [Note] Server hostname (bind-address): '*'; port: 3306

2018-02-07T07:07:39.582368Z 0 [Note] IPv6 is available.

2018-02-07T07:07:39.582390Z 0 [Note]   - '::' resolves to '::';

2018-02-07T07:07:39.583164Z 0 [Note] Server socket created on IP: '::'.

2018-02-07T07:07:39.587350Z 0 [Warning] Failed to open optimizer cost constant tables

2018-02-07T07:07:39.588152Z 0 [ERROR] Fatal error: Can't open and lock privilege tables: Table 'mysql.user' doesn't exist

2018-02-07T07:07:39.588293Z 0 [ERROR] Aborting

有没有大佬给我解答一下，解除我的疑惑！万分感谢！