Solved: MariaDB failed to start with error message "job for mairadb.service failed because the control process exited with error code"

Here are some steps you can follow to resolve the issue:

1. **Check for Running Processes**: As the logs indicate, another process is already using port 3306. You can verify this by running the following command:

   sudo netstat -tulnp | grep 3306

 The command will show you the process ID (PID) of the process using port 3306. Make a note of the PID.

for example,

[root@Pinrecovery ~]# sudo netstat -tulnp | grep 3306

tcp6       0      0 :::3306                 :::*                    LISTEN      110920/mysqld

Here, the process id is: 110920

2. **Stop the Conflicting Process**: Once you identify the PID of the process using port 3306, you can stop it using the `kill` command. Replace `<PID>` with the actual PID you obtained in the previous step:

   sudo kill <PID>

3. **Start MariaDB**: After stopping the conflicting process, try starting the MariaDB service again:

   sudo systemctl start mariadb

4. **Check SELinux**: If you're still having issues with starting MariaDB, ensure that SELinux is not causing any problems. Temporarily disable SELinux to see if it resolves the issue:

   sudo setenforce 0

   However, keep in mind that disabling SELinux is not recommended for security reasons. If SELinux is causing the issue, you should investigate and configure SELinux policies appropriately.

5. **Verify Configuration**: Double-check your MariaDB configuration files (`/etc/my.cnf` or `/etc/mysql/my.cnf`) for any incorrect settings. Ensure that there are no duplicate configurations or conflicts with other services.

6. **Check Hardware/Software Issues**: If the problem persists, investigate for any potential hardware or software issues on your system that might be affecting MariaDB's ability to start.

After attempting the above steps, try starting the MariaDB service again. If the issue persists, review the error messages carefully to understand the root cause, and if needed, seek further assistance from the MariaDB community or forums.