Professionally administering Linux is a very complex matter: it requires advanced skills on the kernel and on a lot of tools and utilities that are often combined in pipelines and scripts.

Professionals having a thorough understanding of the kernel know how to get optimal performance for specific workloads by tuning the right “knobs” and to what degree to do it. In addition to that they know what commands and tools should be used to gather all the information necessary to fix performance issues. This of course requires having a thorough understanding of the kernel scheduler, of memory allocators, of the virtual memory, the Virtual File System and so.

As anybody would expect, skilled professionals thoroughly know the Linux distribution they use – being able to install and remove software packages is absolutely not enough. They should know:

the file system standard layout used by the distro – so to honour it when installing custom software
how to create custom packages (such as RPM) to ease the installation of custom application and scripts
the peculiarities of the initialization process specific of the distribution, in order to sort out boot issues that may arise sooner or later
how to perform automated installations
how to use filesystems, partitioning and Logical Volume Management utilities to apply changes while keeping online the system

And of course a lot of other stuff.

HAProxy Tutorial – A Clean And Tidy Configuration Structure

Posted on October 15, 2024November 14, 2024 by Marco Antonio Carcano

One of the HAProxy strengths is not being very strict about its configuration structure, enabling it to create configurations suitable for fitting very messy scenarios. Sadly this is also its biggest maintainability pitfall: especially if you want to automate its configuration using automation tools and templates, it is up to you to define the best possible standard configuration structure fitting your needs.

The "HAProxy Tutorial - A Clean And Tidy Configuration Structure" post is an insight providing guidelines on how to structure the HAProxy configuration in an effective way, promoting the sharing of floating IP addresses and using easy to edit maps for load balancing the traffic forwarding it to the correct destination. In addition to that, it also provides a way for splitting the statistics so to have them displayed only for the scope of each specific balanced service instead of as a whole.

High Available HA Proxy Tutorial With Keepalived

Posted on October 3, 2024November 14, 2024 by Marco Antonio Carcano

HAProxy is certainly one of the most blazoned, fast and efficient (in terms of processor and memory usage) open source load balancer and proxy, enabling both TCP and HTTP-based applications to spread requests across multiple servers. In the "High Available HA Proxy Tutorial With Keepalived" we see not only how to install it in a High Available fashion, but also how to set the configuration in a clean and tidy way, having it automatically fetched from a Git remote repository.

Ansible roles best practices: practical example gitea role

Posted on July 9, 2024November 14, 2024 by Marco Antonio Carcano

Ansible roles are reusable objects that provide specialized tasks lists, handlers, templates and resource files within a single delivery unit: these objects can be directly accessed from the filesystem, downloaded from Git, from the online Ansible Galaxy of from a Ansible Galaxy compatible local service, such as Pulp 3. Anyway writing custom roles is really a challenging task, especially designing them to be as easy to use and maintain as possible.

The “Ansible roles best practices: practical example gitea role”post guides you into developing a custom Ansible role using a clean and tidy design that you can use as a reference to develop other custom roles.

As use case, we see how to deploy Gitea, a blazoned full featured Git Web UI supporting multiple organizations, providing authentication and authorization facilities enabling to protect repositories and branches, supporting Merge Requests and a lot of other advanced features, with of even a powerful and well standardized API that can be easily exploited by your automations. And, last but not least, ... it is even Java-free.

Ansible playbooks, ansible-galaxy, roles and collections

Posted on May 16, 2024November 14, 2024 by Marco Antonio Carcano

Ansible is a powerful datacenter automation tool that enables nearly declarative automations - "Ansible playbooks, ansible-galaxy, roles and collections" is a primer with Ansible, gradually introducing concepts that we better elaborate in other posts following this one: as we already said, Ansible is a powerful tool, and as many powerful tool can make more pain than benefits if improperly managed - the aim of this post is providing a good baseline that enable quickly enable operating Ansible running ad hoc statements, playbooks and operating using Ansible Galaxy with shelf roles and collections .

This post begins where we left with the "Ansible Tutorial – Ansible Container How-To" post, writing a playbook for preparing hosts for being managed by Ansible, learning how to use Ansible Galaxy for downloading and installing shelf Ansible roles and collections. The outcome will be a running PostgreSQL instance we will use as the DB engine in the next post of the series..

Ansible Tutorial – Ansible Container Howto

Posted on May 15, 2024November 14, 2024 by Marco Antonio Carcano

Ansible is a powerful datacenter automation tool that enables nearly declarative automations - "Ansible Tutorial - Ansible Container Howto" is the first of a series of posts dedicated to Ansible, paying particularly attention at "doing all-right": Ansible is a powerful tool, and as many powerful tool can make more pain than benefits if improperly managed.

In this post we see how to quickly set up a containerised Ansible on a workstation, configuring the environment so that it can be run from the shell without explicitly invoking podman, providing a very friendly user experience the same way, enabling it to run statements as it was really installed on the system.

X Window Tutorial – X Display Server HowTo And Cheatsheet

Posted on April 17, 2024November 14, 2024 by Marco Antonio Carcano

Even just because of its very long service lifetime, it is certainly worth the effort to have a look at this amazing piece of software. It does not matter if we are about to switch to Wayland (that by the way cannot completely replace the whole X Window System - think for example to XDMCP): the truth is that systems running X Windows will stay here for 10 years more, so 'm sure it is still worth the effort to have a good understanding of it. The "X Window Tutorial - X Display Server HowTo And Cheatsheet" post provides you with all the necessary skills to become an expert on this amazing piece of software that really made the story of UNIX and Linux.