Step 3 — (Optional) Adjusting User Authentication and Privileges

In Ubuntu systems running MySQL 5.7 (and later versions), the root MySQL user is set to authenticate using the auth_socket plugin by default rather than with a password. This allows for some greater security and usability in many cases, but it can also complicate things when you need to allow an external program (e.g., phpMyAdmin) to access the user.

In order to use a password to connect to MySQL as root, you will need to switch its authentication method from auth_socket to mysql_native_password. To do this, open up the MySQL prompt from your terminal:

• sudo mysql

Next, check which authentication method each of your MySQL user accounts use with the following command:

• SELECT user,authentication_string,plugin,host FROM mysql.user;

+------------------+-------------------------------------------+-----------------------+-----------+
| user             | authentication_string                     | plugin                | host      |
+------------------+-------------------------------------------+-----------------------+-----------+
| root             |                                           | auth_socket           | localhost |
| mysql.session    | *THISISNOTAVALIDPASSWORDTHATCANBEUSEDHERE | mysql_native_password | localhost |
| mysql.sys        | *THISISNOTAVALIDPASSWORDTHATCANBEUSEDHERE | mysql_native_password | localhost |
| debian-sys-maint | *CC744277A401A7D25BE1CA89AFF17BF607F876FF | mysql_native_password | localhost |
+------------------+-------------------------------------------+-----------------------+-----------+
4 rows in set (0.00 sec)

In this example, you can see that the root user does in fact authenticate using the auth_socket plugin. To configure the root account to authenticate with a password, run the following ALTER USER command. Be sure to change password to a strong password of your choosing, and note that this command will change the root password you set in Step 2:

• ALTER USER ‘root’@’localhost’ IDENTIFIED WITH mysql_native_password BY ‘password‘;

Then, run FLUSH PRIVILEGES which tells the server to reload the grant tables and put your new changes into effect:

• FLUSH PRIVILEGES;

Check the authentication methods employed by each of your users again to confirm that root no longer authenticates using the auth_socket plugin:

• SELECT user,authentication_string,plugin,host FROM mysql.user;

+------------------+-------------------------------------------+-----------------------+-----------+
| user             | authentication_string                     | plugin                | host      |
+------------------+-------------------------------------------+-----------------------+-----------+
| root             | *3636DACC8616D997782ADD0839F92C1571D6D78F | mysql_native_password | localhost |
| mysql.session    | *THISISNOTAVALIDPASSWORDTHATCANBEUSEDHERE | mysql_native_password | localhost |
| mysql.sys        | *THISISNOTAVALIDPASSWORDTHATCANBEUSEDHERE | mysql_native_password | localhost |
| debian-sys-maint | *CC744277A401A7D25BE1CA89AFF17BF607F876FF | mysql_native_password | localhost |
+------------------+-------------------------------------------+-----------------------+-----------+
4 rows in set (0.00 sec)

You can see in this example output that the root MySQL user now authenticates using a password. Once you confirm this on your own server, you can exit the MySQL shell:

• exit

Alternatively, some may find that it better suits their workflow to connect to MySQL with a dedicated user. To create such a user, open up the MySQL shell once again:

• sudo mysql

Note: If you have password authentication enabled for root, as described in the preceding paragraphs, you will need to use a different command to access the MySQL shell. The following will run your MySQL client with regular user privileges, and you will only gain administrator privileges within the database by authenticating:

• mysql -u root -p

From there, create a new user and give it a strong password:

• CREATE USER ‘sammy‘@’localhost’ IDENTIFIED BY ‘password‘;

Then, grant your new user the appropriate privileges. For example, you could grant the user privileges to all tables within the database, as well as the power to add, change, and remove user privileges, with this command:

• GRANT ALL PRIVILEGES ON *.* TO ‘sammy‘@’localhost’ WITH GRANT OPTION;

Note that, at this point, you do not need to run the FLUSH PRIVILEGES command again. This command is only needed when you modify the grant tables using statements like INSERT, UPDATE, or DELETE. Because you created a new user, instead of modifying an existing one, FLUSH PRIVILEGES is unnecessary here.

Following this, exit the MySQL shell:

• exit

Finally, let’s test the MySQL installation.

Source: How To Install MySQL on Ubuntu 18.04 | DigitalOcean