phpMyAdmin からログインしようとした時に、はまったのでメモ書きする事にしました。

ログイン画面からログインしようとすると以下のエラーメッセージが表示されました。

mysqli::real_connect(): (HY000/1698): Access denied for user 'root'@'localhost'

MariaDBを使用してましたが、パスワードを以下のコマンドより設定している状態でした。

SET PASSWORD FOR root@localhost=password('パスワード');

また、パスワードを設定後に、以下のセキュリティ強化のコマンドを実行してました。

mysql_secure_installation

mysql_secure_installationの実行結果の情報です。

NOTE: RUNNING ALL PARTS OF THIS SCRIPT IS RECOMMENDED FOR ALL MariaDB
      SERVERS IN PRODUCTION USE!  PLEASE READ EACH STEP CAREFULLY!

In order to log into MariaDB to secure it, we'll need the current
password for the root user. If you've just installed MariaDB, and
haven't set the root password yet, you should just press enter here.

Enter current password for root (enter for none):
OK, successfully used password, moving on...

Setting the root password or using the unix_socket ensures that nobody
can log into the MariaDB root user without the proper authorisation.

You already have your root account protected, so you can safely answer 'n'.

Switch to unix_socket authentication [Y/n] n
 ... skipping.

You already have your root account protected, so you can safely answer 'n'.

Change the root password? [Y/n] n
 ... skipping.

By default, a MariaDB installation has an anonymous user, allowing anyone
to log into MariaDB 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? [Y/n] 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? [Y/n] y
 ... Success!

By default, MariaDB 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? [Y/n] 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? [Y/n] y
 ... Success!

Cleaning up...

All done!  If you've completed all of the above steps, your MariaDB
installation should now be secure.

Thanks for using MariaDB!

MariaDBに、以下のコマンドを使用してログインする。

mysql -u root -p

以下のコマンドを実行して、パスワードの設定情報を確認する。

select user,host,password from mysql.user;

パスワードの設定情報の内容です。

MariaDB [(none)]> select user,host,password from mysql.user;
+------+-----------+----------+
| User | Host      | Password |
+------+-----------+----------+
| root | localhost | invalid  |
+------+-----------+----------+

password が、invalid になっている！？

通常は、以下のように password の部分が英数字が記入されているはずだけど・・・

+------------------+-----------------+-------------------------------------------+
| user             | host            | password                                  |
+------------------+-----------------+-------------------------------------------+
| root             | localhost       | *E8D868B7DA46FC9F996DC761C1AE0175xxxxxxxxx|
+------------------+-----------------+-------------------------------------------+

再度、以下のコマンドでパスワードを設定する。

SET PASSWORD FOR root@localhost=password('パスワード');

パスワードを再設定する事で、phpMyAdmin からログインできるようになりました。