Guide to Centos Installation and Root Access on CloudStack

Introduction After installing the Centos operating system on CloudStack, you usually log in with the username centos. However, in some cases, root access may be required. This guide explains step-by-step how to log in to the system with the centos user, obtain root access, and optionally create a password for the root user.

Step-by-Step Guide

  1. Log in with the Centos User:

    • Connect to the Centos server you created in the CloudStack console using SSH or VNC.
    • Log in using the username centos and your password.

  2. Root Access with the Sudo Command:

    • Run the following command in the terminal:
      Bash

      sudo -s
    • This command gives you root privileges. You can now run commands as the root user.

  3. Create a Root Password (Optional):

    • Why Create a Root Password: For security reasons, it’s important to create a password for the root user. This prevents unauthorized access to the root account.
    • Create Password:
      Bash

      passwd

      This command will prompt you to enter a new password. Make sure you create a strong password.

  4. Direct Login with the Root User (Optional):

    • SSH Configuration:
      • Open the SSH configuration file:
        Bash

        nano /etc/ssh/sshd_config
      • Find the following line and change the value to yes: 
        PermitRootLogin yes
      • Save the file by pressing Ctrl+X, then Y, and Enter.
      • Restart the SSH service:
        Bash

        systemctl restart sshd
    • You can now log in directly to the system using the root username and the new password you created.

Important Notes:

  • Security: Be careful with root privileges. Incorrect commands can crash your system.
  • Sudoers File: If you have multiple users on your system, you can edit the sudoers file to define which users can run which commands.
  • SSH Key: We recommend using SSH keys for a more secure login.
  • Strong Password: Create a strong and unique password for the root user.

Resetting Your MYSQL Root Password

  1. The first step to resetting your root MySQL password on a Linux server is to stop MySQL. If you have a monitoring service for MySQL that will restart the service if it is down, make sure that service is also stopped for the time being, such as checkservd and cPanel. 
    /etc/init.d/mysql stop
  2. Next, start MySQL in Single User Mode and enter without a password.

    Warning:
    Restarting MySQL this way will allow anyone access to every database. To avoid this, stop eth0 and fuser -k any logged in user and touch /etc/nologin. 
    mysqld_safe --skip-grant-tables & mysql

    Note:
    Make sure to add & or the command prompt will not show.
  3. Enter the following commands in the MySQL prompt. The password below is only an example, replace 123456ABCDEF with the password of your choice. Our article Best Practice: Creating a Secure Password provides you with information on secure password best practices. 
    UPDATE mysql.user SET password=password("123456ABCDEF") 
WHERE user='root';
FLUSH PRIVILEGES;
exit;
  4. Stop MySQL safe and start MySQL and all other services that kept it from restarting like checkservd and cPanel normally. 
    /etc/init.d/mysql stop
/ect/init.d/mysql start
  5. Test your change by doing a test login, to log into MySQL, type it into the command line. 
    mysql
  6. You will be prompted to enter your password. Enter the new password, if you are logged in then you have successfully reset the MySQL root password.

Note:
If the MySQL user has been deleted, run the following query to recreate it:

INSERT INTO `mysql`.`user` ( `Host` , `User` , `Password`
 , `Select_priv` ,`Insert_priv` , `Update_priv` ,`Delete_priv` 
 , `Create_priv` , `Drop_priv` , `Reload_priv` , `Shutdown_priv` 
 , `Process_priv` , `File_priv` , `Grant_priv` , `References_priv` 
 , `Index_priv` , `Alter_priv` , `Show_db_priv` , `Super_priv` 
 ,`Create_tmp_table_priv` , `Lock_tables_priv` , `Execute_priv` 
 , `Repl_slave_priv`, `Repl_client_priv` , `Create_view_priv` 
 , `Show_view_priv` , `Create_routine_priv` , `Alter_routine_priv` 
 , `Create_user_priv` , `max_questions` , `max_updates`
 , `max_connections` , `max_user_connections` ) VALUES ( 'localhost'
 , 'root',PASSWORD('password1234'), 'Y', 'Y', 'Y', 'Y', 'Y', 'Y', 'Y'
 , 'Y', 'Y', 'Y', 'Y', 'Y', 'Y', 'Y', 'Y', 'Y', 'Y','Y', 'Y', 'Y', 'Y'
 , 'Y', 'Y', 'Y', 'Y', 'Y', '0', '0', '0', '0' );

Troubleshooting

You may encounter an error when trying to change the root password that looks like the example below:

mysql> show warnings; +---------+------+-----------------------------------------------+ 
| Level | Code | Message | +---------+------+-----------------------------------------------+ 
| Warning | 1265 | Data truncated for column 'Password' at row 1 | 
| Warning | 1265 | Data truncated for column 'Password' at row 2 | 
+---------+------+-----------------------------------------------+

 

If MySQL is giving you warnings when changing the password, type the following:
mysql>prompt

 

Then leave MySQL and run:

/usr/bin/mysql_fix_privilege_tables

Once this is complete, try to set the password again. If you have further issues, please contact our Support team and we will be happy to assist you!