Day 7 Task: Understanding package manager and systemctl

?? DevOps Student's 90-Day Challenge: Day 7 - Understanding Package Managers and systemctl ??

Welcome back to Day 7 of the 90-Day DevOps Challenge! In today's session, we will dive into the world of package managers in Linux and explore the utility of 'systemctl' and 'systemd.' These are fundamental tools for DevOps practitioners, and understanding them is essential for managing software packages and services effectively.

?? Package Managers: The Heart of Software Management

What is a Package Manager in Linux?

In the Linux ecosystem, a package manager is your go-to tool for managing software packages efficiently. It simplifies the installation, removal, upgrading, configuration, and overall management of software on your operating system. Whether you prefer a graphical interface like a software center or the command line, package managers make it all possible. Common package manager commands include 'apt-get,' 'pacman,' 'yum,' and 'dnf.'

But before we dive deeper into package managers, let's clarify what a "package" is.

?? Understanding Packages

A package typically refers to an application, be it a GUI program, a command-line tool, or a software library essential for other programs to function. Essentially, a package is an archive file bundling together the binary executable, configuration files, and sometimes information about its dependencies.

?? Different Kinds of Package Managers

Package managers vary based on the packaging system, and sometimes multiple package managers can coexist for the same system. For instance, the RPM packaging system has 'Yum' and 'DNF' package managers, while the DEB system offers 'apt-get' and 'aptitude' as command-line package managers.

??? Putting Knowledge into Practice: Installing Docker and Jenkins

Now that we've got a grasp of what package managers are and how they work let's put this knowledge into practice. Your tasks for today are to install Docker and Jenkins on your system using package managers. We'll cover installation on both Ubuntu and CentOS.

?? Installing Docker and Jenkins on Ubuntu

?? Installing Docker and Jenkins on CentOS

After completing these installations, you'll have Docker and Jenkins up and running on your system, thanks to the power of package managers.

?? systemd: The System and Service Manager

'systemd' is a system and service manager used on many Unix-like operating systems. It plays a crucial role in managing processes, services, and other system resources. It's a fundamental component in modern Linux distributions.

?? Using systemctl

'systemctl' is the command you'll use to examine and control the state of the 'systemd' system and service manager. It offers a unified interface to manage system services, making it easier to perform tasks like starting, stopping, enabling, or disabling services.

1. Check the status of the Docker service on your system:

Here are some tasks to get you started:

1. Stop the Jenkins service and capture before and after screenshots to observe the service's status change.

(ps ignore the date and time in the image that is for just information purpose)

3. Read about the commands systemctl vs service

systemctl and service are both tools used to manage and control services on a Linux system. However, they have some differences:

1. systemctl is the newer tool and is used on systems that use the Systemd init system, which is now widely adopted as the default init system for many popular Linux distributions, including Fedora, Red Hat Enterprise Linux, and Ubuntu.
2. service is the older tool and is used on systems that use the System V init system, which was the previous standard init system used in many popular Linux distributions.
3. systemctl provides more advanced features compared to service, such as the ability to manage units, which are the basic building blocks of Systemd. This allows you to manage not just services, but also other system components, such as sockets, devices, and mount points, with a unified interface.
4. service is limited to managing services only, and its syntax and options are not as advanced as those of systemctl.

systemctl commands :

• systemctl start <service-name>
• systemctl stop <service-name>
• systemctl restart <service-name>
• systemctl enable <service-name>
• systemctl disable <service-name>
• systemctl status <service-name>

service commands :

• service <service-name> start
• service <service-name> status
• service <service-name> stop
• service <service-name> restart

Mastering these commands will help you become proficient in managing services effectively.

Congratulations on completing Day 7 of the 90-Day DevOps Challenge! You've gained valuable insights into package managers and service management, essential skills for any DevOps enthusiast.

Stay tuned for more exciting challenges and continue to build your DevOps expertise. ????

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