Tech Tutorial: Operate Running Systems #
Introduction #
Operating running systems effectively involves managing various network services that are crucial for the system’s functionality and connectivity. For Red Hat Certified System Administrator (RHCSA) exam takers, understanding how to start, stop, and check the status of these services is essential. This tutorial will focus exclusively on Red Hat Enterprise Linux (RHEL) commands and tools to manage network services, ensuring that learners are well-prepared for the exam and real-world system administration.
Step-by-Step Guide #
In RHEL, network services are typically managed through systemctl
commands, part of the systemd
suite, which is the init system and service manager from RHEL 7 onward. We will cover how to use systemctl
to start, stop, and check the status of services. Additionally, we will briefly discuss the use of service
and chkconfig
commands for RHEL 6 compatibility.
1. Checking the Status of Network Services #
To check the status of a service in RHEL, you use the systemctl status
command. This command provides detailed information about a service, including whether it is active, the start-up type, and recent log entries.
Example:
sudo systemctl status httpd
This command checks the status of the Apache HTTP Server (httpd
). It will show whether httpd
is running, stopped, or in any error state.
2. Starting Network Services #
To start a service in RHEL, use the systemctl start
command. This command is used when you want to manually start a service that is not running.
Example:
sudo systemctl start httpd
This command will start the Apache HTTP Server if it is not already running.
3. Stopping Network Services #
To stop a running service, use the systemctl stop
command. This is useful when you need to perform maintenance or configuration changes that require the service to be stopped.
Example:
sudo systemctl stop httpd
This command stops the Apache HTTP Server if it is currently running.
4. Enabling and Disabling Services #
Enabling a service sets it to start automatically at boot, while disabling it does the opposite. This is controlled with systemctl enable
and systemctl disable
.
Example to enable a service:
sudo systemctl enable httpd
Example to disable a service:
sudo systemctl disable httpd
5. Restarting and Reloading Services #
If you need to apply configuration changes or update a service without stopping it completely, you can use systemctl restart
to restart the service or systemctl reload
to reload its configuration.
Example to restart a service:
sudo systemctl restart httpd
Example to reload a service:
sudo systemctl reload httpd
Detailed Code Examples #
Let’s consider a scenario where we need to set up a LAMP stack on a RHEL server.
- Install Apache HTTP Server:
sudo yum install httpd
- Start and enable Apache to run at boot:
sudo systemctl start httpd
sudo systemctl enable httpd
- Check the status to ensure it’s running:
sudo systemctl status httpd
- Install MariaDB:
sudo yum install mariadb-server
- Start and enable MariaDB:
sudo systemctl start mariadb
sudo systemctl enable mariadb
- Secure MariaDB installation:
sudo mysql_secure_installation
- Install PHP:
sudo yum install php php-mysql
- Restart Apache to apply PHP integration:
sudo systemctl restart httpd
Conclusion #
Mastering the use of systemctl
commands is crucial for managing network services on a RHEL system. This tutorial provides a foundation for starting, stopping, checking status, and managing the automatic start of services with systemctl
. For those preparing for the RHCSA exam, proficiency in these tasks is essential, as they form the backbone of effective system administration in RHEL environments.