mysqldが起動できない。 ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/var/lib/mysql/mysql.sock' (2)

[System][MY-010116] [Server] /usr/sbin/mysqld (mysqld 8.0.16) starting as process 20744
[System][MY-013381] [Server] Server upgrade from '80015' to '80016' started.
[ERROR][MY-013384] [Server] Could not create server upgrade info file at '/var/lib/mysql/'.
[ERROR][MY-013380] [Server] Failed to upgrade server.
[ERROR][MY-010119] [Server] Aborting


【対処】
# mv /var/lib/mysql/mysql_upgrade_info /var/lib/mysql/mysql_upgrade_info.bak
# systemctl start mysqld


# vi /var/log/mysqld.log

[System] [MY-010116] [Server] /usr/sbin/mysqld (mysqld 8.0.16) starting as process 21873
[System] [MY-013381] [Server] Server upgrade from '80015' to '80016' started.
[System] [MY-013381] [Server] Server upgrade from '80015' to '80016' completed.

無事起動した。

※8.0.16からデータベースのアップグレードが自動になったもよう。