What approaches and methods are used to launch and configure systems in CentOS?

In CentOS, the main methods and tools for starting and configuring systems include:

1. systemd — the primary system and service manager. Using systemctl, you can start, stop, restart, and enable services.

   Example:

   systemctl start httpd
   systemctl enable httpd  # enable at boot
   systemctl status httpd
   

2. Configuration files — services are usually configured through files in /etc/.

3. init scripts — in older CentOS versions, scripts in /etc/init.d/ were used, but now systemd is preferred.

4. firewalld — for firewall configuration and network rules management.

5. SELinux — for security policy management, important in system setup.

6. cron — for scheduling tasks.

Thus, the main method for system startup and configuration in CentOS is using systemd and related tools, along with proper service and system parameter configuration.