#経緯
MySQLの設定をする際に初期パスワードが自動発行されていることを知らなかったため、記事に残しました。

Conohaのサポートブログ
https://support.conoha.jp/v/setupmysql/

#問題点

▼SQLのセキュリティ設定の際に下記のエラーで躓いてしまった

$ mysql_secure_installation
Securing the MySQL server deployment.

Enter password for user root: 
Error: Access denied for user 'root'@'localhost' (using password: YES)

#解決

どうやらSQLには初期パスワードが事前に発行されているようです。
初期パスワードの格納場所は/var/log/mysqld.log
▼root@localhost:の後ろが初期パスワードです

$ cat /var/log/mysqld.log

~~省略~~
[Note] [MY-010454] [Server] A temporary password is generated for root@localhost: [初期パスワード]

▼mysql_secure_installationで初期パスワードを入力し新しいパスワードを設定


$ mysql_secure_installation

Securing the MySQL server deployment.

Enter password for user root: [初期パスワード]

The existing password for the user account root has expired. Please set a new password.

New password: [新しいパスワード]

Re-enter new password: [もう一度新しいパスワード]
The 'validate_password' component is installed on the server.
The subsequent steps will run with the existing configuration
of the component.
Using existing password for root.

Estimated strength of the password: 100 
Change the password for root ? ((Press y|Y for Yes, any other key for No) : y

New password: [新しいパスワード]

Re-enter new password: [もう一度新しいパスワード]

Estimated strength of the password: 100 
Do you wish to continue with the password provided?(Press y|Y for Yes, any other key for No) : y
By default, a MySQL installation has an anonymous user,
allowing anyone to log into MySQL without having to have
a user account created for them. This is intended only for
testing, and to make the installation go a bit smoother.
You should remove them before moving into a production
environment.

Remove anonymous users? (Press y|Y for Yes, any other key for No) : y
Success.


Normally, root should only be allowed to connect from
'localhost'. This ensures that someone cannot guess at
the root password from the network.

Disallow root login remotely? (Press y|Y for Yes, any other key for No) : y
Success.

By default, MySQL comes with a database named 'test' that
anyone can access. This is also intended only for testing,
and should be removed before moving into a production
environment.


Remove test database and access to it? (Press y|Y for Yes, any other key for No) : y
 - Dropping test database...
Success.

 - Removing privileges on test database...
Success.

Reloading the privilege tables will ensure that all changes
made so far will take effect immediately.

Reload privilege tables now? (Press y|Y for Yes, any other key for No) : y
Success.

All done!

▼参考サイト
https://weblabo.oscasierra.net/mysql-57-init-setup/