Problems after installing MySql on Linux WSL - mysql

Question

After a new installation of MySQL on WSL linux distribution a whole sequence of issues ocurred. Solutions are described on different posts, but I thought it would be good to have them on one place, since it concerns clean new installations of both mysql and WSL on a new Windows 11 PC, without any previous configuration changes, so 100% reproducible with the given versions. I followed the installation manuals for WSL and mysql expecting this would work out-of-the-box. My intention was to run MySQL instance on WSL and connect to it from MySQL Workbench running on the hosting Windows. Below is description of steps I've performed and how I solved the issues which occurred. Maybe it helps someone in the same scenario, or maybe someone can propose better solutions.
WSL installation
On a (new) Windows 11 PC, executed PowerShell command:
wsl --install -d Ubuntu
This installed Ubuntu 22.04.1 LTS
In the distribution set up username/password and performed necessary updates and upgrades according to https://learn.microsoft.com/en-us/windows/wsl/install.
MySQL installation
According to https://learn.microsoft.com/en-us/windows/wsl/tutorials/wsl-database
$ sudo apt install mysql-server
This installed:
mysql Ver 8.0.31-0ubuntu0.22.04.1 for Linux on x86_64 ((Ubuntu))
Tried to start the instance:
$ sudo /etc/init.d/mysql start
Following warning was reported during the instance startup:
su: warning: cannot change directory to /nonexistent: No such file or directory
MySQL uses a user named 'mysql' who has '/nonexistent' set up as the home directory after installation. The home directory is registered in the file '/etc/passwd'. When you open the file in an editor, you will see the line for 'mysql' user with the '/nonexistent:' directory.
mysql:x:108:117:MySQL Server,,,:/nonexistent:/bin/false
This directory has to be changed to an existing one, e.g.: '/var/lib/mysql'. For this the instance must be stopped first:
$ sudo /etc/init.d/mysql stop
Then the home directory can be set with the command:
$ sudo usermod -d /var/lib/mysql/ mysql
After this the instance will start without the previous warining, but the following error appeared:
Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (13)
To solve this error, find where the mentioned mysqld.sock file is located. Do not stop the instance before running the command:
$ sudo find / -type s
Find the file in the output, in my case it was: '/run/mysqld/mysqld.sock'.
Find 'my.cnf' file under '/etc', in my case: '/etc/mysql/my.cnf'. Edit this file, do not use the Windows notepad.exe, but better notepad++, in order not to change the encoding, or add extra '.txt' extension.
Add following lines at the end of the file, using the exact file location:
[mysql]
socket=/run/mysqld/mysqld.sock
I have searched for references to '/var/run' path in other .cnf files under '/etc/mysql' directory and changed them to '/run', because the '/var/run' does not exist on my distribution.
After this step, the instance can be started without any errors, or warnings.
Set up MySQL root user
While is was possible to start mysql with:
$ sudo mysql
There attempt to access the instance with the root user:
$ mysql -u root -p
Resulted in error:
Access denied for user 'root'#'localhost' (using password: NO)
The user was pre-created during installation without password, but yet cannot access the instance. To fix this issue, the 'root' user needs to be re-created:
$ sudo mysql
mysql> drop user 'root'#'localhost';
mysql> create user 'root'#'localhost' identified by '' ;
mysql> grant all privileges on *.* to 'root'#'localhost' WITH GRANT OPTION;
mysql> flush privileges;
Connect from Workbench running on Windows
For connecting to Workbench, I've tried to use previously configured 'root' user without password.
First the IP address of WSL needs to be detected. One way is to install net-tools and use ifconfig command:
$ sudo apt install net-tools
$ ifconfig
Then, the IP address can be seen under <BROADCAST, RUNNING, MULTICAST> section in the output:
eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 192.168.114.54 netmask 255.255.240.0 broadcast 192.168.127.255
Here it was 192.168.114.54
Simpler way is to get this address from Windows PowerShell command:
wsl hostname -I
Using this address from Workbench resulted in error connecting to the server. I've solved this problem by changing the 'bind-address' setting found in the '/etc/mysql/mysql.conf.d/mysqld.cnf' file. This was previously set to 127.0.0.1. It had to be changed to:
bind-address=0.0.0.0
After this step, connection attempt from Workbench resulted in access error for the 'root' user, but it confirmed, that server was now accessible:
Failed to Connect to MySQL at 192.168.114.54:3306 with user root
Access denied for user 'root'#'192.168.112.1'
Problem with the 'root' user accessing the instance was, that each MySQL user is bound to a specific host. In my case the 'root' was bound to 'localhost'. I needed to create a new 'root' user bound to '192.168.112.1':
mysql> create user 'root'#'192.168.112.1' identified by '';
mysql> grant all privileges on . to 'root'#'192.168.112.1' WITH GRANT OPTION;
mysql> flush privileges;
After this step I could connect to MySQL instance from Workbench running on the hosting Windows without errors.