Systems

Compilation of a C-program using a Makefile

Introduction The compilation of programs in programming language C is a fundamental process in software development. It allows the source code written by the programmers to be translated into computer-friendly instructions. One of the challenges associated with the compilation is the efficient management of the project files and units, which becomes even more crucial when working on large and complex projects. This work aims to explore one of the most used mechanisms to compile projects in C: the use of a Makefile file. A Makefile is a configuration file that describes how to compile the source files of a project and how to manage the units between them. In addition, it allows to automate the compilation process and facilitates the task of maintaining and updating the code.

Wednesday, November 29, 2023 | 4 minutes Read

Compilation of a kernel

Introduction For the practice I will choose the kernel 6.4.4 that I have downloaded from the backports repository: To download the source code we will use apt source: It will create us a directory with the source code If we list the contents of the directory with the source code, we will see that the structure is the same as to compile a package in C.

Wednesday, November 29, 2023 | 4 minutes Read

Creation of an automated installation system

Automatic installation of an iso On the official debian page we will download a debian image, in my case I have selected a netinstall: Once you download the debian image, we will copy its content into a folder to then make some modifications. To do this we will mount the iso as a loop device: Once mounted we can see its content: We’re going to make a copy of the files we’re going to use to a directory of ours to make changes to them, once we do this we can dismount the image:

Wednesday, November 29, 2023 | 3 minutes Read

Kernel parameter modification exercises

1.Disable apparmor in boot. 2.Disable if possible the Kernel Mode Setting (KSM) of the graphics card. We add the following line in the group configuration: We update the grub to apply the changes: 3 Change the swappiness provisionally so that your equipment swap is activated when more than 90% of the RAM is used. 4 Make swappiness change permanent. You have to run sysctl -p sudo to be applied. 5.Show the value of the forward bit for IPv6.

Wednesday, November 29, 2023 | 1 minute Read

Migtation from CentOS stream 8 to CentOS stream 9

Update the packages Before migrating, make sure your CentOS Stream 8 system has all the latest packages and updates. Eliminate unnecessary packages that appear to us when using the next command as they are orphaned packages Update to CentOS9 Install CentOS 9 repositories: Now let’s update the packages to CentOS 9: When the installation is finished, some packages may be removed: We update the database of the local packages:

Wednesday, November 29, 2023 | 2 minutes Read

Module management exercises

1.Check the loaded modules on your computer. 2.Count the number of modules available in the kernel you are using. 3 Connect a USB pencil and watch the output of the dmesg sudo instruction. We see how the kernel detects the usb device and the necessary modules are loaded for it: We see how the number of modules loaded has increased: 4.Eliminate the module for some non-essential dispotive and check what happens. Put it back on. If we download it we will not be able to make use of exfat file systems:

Wednesday, November 29, 2023 | 2 minutes Read

Packaging management

Indicates the steps to be followed to modify DHCP network configuration to static To configure the ens1 interface with a static IP address (e.g. 192.168.122.10), you must modify the / etc / sysconfig / network-scripts / ifcfg-ens1 file: To apply the configuration we restart the Network Manager: Update the system to the latest versions of the installed packages Install the additional EPEL repository. Install the bash- completion package.

Wednesday, November 29, 2023 | 1 minute Read

Paid management exercises

Work with apt, aptitude, dpkg Exercise 1 What actions I get when performing apt update and apt upgrade. Explain in detail. The apt update command is the first fundamental step in the package update. It takes the following actions: -**Recovers Remote Metadata:**apt update communicates with online software repositories and recovers metadata related to available packages. These metadata include information on the latest versions of the packages, their dependencies and other essential information. -Update the Local Metadata Copy: Then apt reconstructs and updates the local copy of these metadata. This allows the system to quickly access information about the packages without having to download it repeatedly.

Wednesday, November 29, 2023 | 10 minutes Read

Transformation instance cloud

Creation of the LVM scheme We installed the LVM2 package Now we’ll create the partitions on the second disk: We create the group of volumes: We create the root and home volumes: The partitions must have the following format: -vdb2 etx4 FJCD-vg-home ext4 -FJCD-vg-raiz ext4 We would have to format the efi: So would our partition scheme: Copy the partition content Now let’s ride the partitions:

Wednesday, November 29, 2023 | 1 minute Read

Active Directory in Ubuntu

In this post, we will explore how to set up an Active Directory environment on an Ubuntu server using tools such as Kerberos and Samba. Active Directory is an integral Microsoft solution for identity management and access control in business networks. Through this guide, we will learn step by step how to implement a Ubuntu server as a domain controller, establish Kerberos-based authentication and configure directory services by using Samba.

Wednesday, September 20, 2023 | 20 minutes Read

Centralized collection of system log, using journald

Step 1 Install system -journal-remote In our environment, the first step will be to install the system-journal- remote package, which will allow us to access these machines remotely. To carry out the installation on our stage machines, we will use the apt package manager in Odin, which runs Debian 12. We will also install the same package in Thor and Loki, which are containers housed within Odin. As for Hela, a Rocky operating system, it will require the use of dnf for installation.

Wednesday, September 20, 2023 | 7 minutes Read

Disposal of systemd

Systemd and System V (SysV) are two start-up systems used in Linux distributions to manage system and service boot. System V (SysV) is a traditional start-up system that uses shell scripts stored at different running levels (runlevels) to start and stop services sequentially. It was widely used in many Unix and Linux distributions for decades. On the other hand, Systemd is a more modern and advanced start-up system that replaces SysV. Incorporated to improve system start speed and efficiency, systemd uses a unit-based approach and depends on paralleling to start services simultaneously. It also includes additional features such as service management, sockets, timers, and dependencies, making it a more robust and flexible option compared to SysV.

Wednesday, September 20, 2023 | 3 minutes Read