GIT Tutorial – A thorough Git Howto About Using Remotes

Posted on September 19, 2022October 6, 2022 by Marco Antonio Carcano

Git is certainly the most popular Source Code Management (SCM) software: it is broadly used in almost every recent open source project, and even a lot of emblazoned legacy projects switched to it over the years.

In the previous post we thoroughly learned how to use it to version control sources, working only on personal - so local - repositories.

GIT Tutorial - A thorough Git Howto About Using Remotes completes our trip on learning how to professionally use Git, showing you how to link the personal local repository to shared remote bare repositories.
Knowing how to deal with this topic is of course a mandatory skill, since this is the only way you have to cooperate and work with other developers.

GIT Tutorial – A thorough Version Control with Git Howto

Posted on September 5, 2022October 6, 2022 by Marco Antonio Carcano

DevOps (and of course DevSecOps) are getting more and more adopted by companies: these methodologies rely on several frameworks and software skills, and working with a modern Source Code Management (SCM) such any kind of software implementing Git is certainly a must for every DevOps professional. This post is the first of a set of posts dedicated to Git and is aimed at providing a GIT Tutorial - A thorough Version Control with Git Howto on personal repositories, giving guidelines to proficient operating with it.
Read more >

A quick, easy yet comprehensive GPG tutorial

Posted on July 28, 2022July 28, 2022 by Marco Antonio Carcano

GnuPG is a freely available command line encryption suite based on OpenPGP encryption library, and it is probably the most used encryption suite in the world. Every IT professional sooner or later face use cases that require to know how to handle it, but the point is that, despite a trivial usage of this suite may look quite easy, there are some not so obvious nuances that if known can really improve the experience, also saving from making some hidden mistakes that can really painful if anything would go wrong.

This is a quick, easy yet comprehensive GPG tutorial with the aim to provide a quick yet thorough explanation of how to safely use this amazing encryption suite.

The Ultimate AWK Tutorial For Professionals

Posted on June 14, 2022July 6, 2022 by Marco Antonio Carcano

AWK is a powerful pattern scanning and processing language developed by Alfred Aho, Peter Weinberger and Brian Kernighan at Bell Labs - the name of this tool is indeed derived by concatenating the letter of their surnames to one another. It is one of that tools that every Linux professionals (not only the more seasoned ones) must be skilled on, since it is broadly used in a lot of shell scripts that very often are inherited from predecessors and that must be maintained: the sad truth is that very often is not worth the effort to rewrite them using other more modern languages, so knowing how to deal with it can really ease your life. And anyway, ... sometimes it requires much less time to code an AWK one liner than a Python script, so knowing how and when to use AWK is certainly a valuable skill still nowadays.
The aim of "The Ultimate AWK Tutorial For Professionals" is not to provide a complete explain about how to code with AWK - there are more modern and handy languages such as Python nowadays: I just want to provide a very quick yet comprehensive walkthrough on it focusing on how to write AWK one-liners that are often embedded in shell scripts or that you can use to sort out common system administration tasks. That's why I'm also showing some real-life use cases with AWK one-liners that can very quickly and easily sort things out.

Managing Red Hat Network Satellite Clients With Ansible Roles And Playbooks

Posted on June 9, 2022June 16, 2022 by Marco Antonio Carcano

Managing Red Hat Network Satellite clients with Ansible roles and playbooks is a very powerful feature of Red Hat Network Satellite Server 6, as well as of its upstream project Katello. Conversely from Puppet, that requires the client host to install its agent package and to be registered to the Puppet master running on the Satellite or Capsule, Ansible does not require installing anything, since it relies on SSH or, to tell it in Red Hat Network Satellite 6 terms, it relies on remote execution with SSH.

This post shows you how to manage client hosts using Ansible, either executing the Ansible roles assigned to the host group the client host belongs to, or running Ansible playbooks using Job Templates.

The Linux distribution used in the examples is CentOS 7, but you can of course easily adapt it to any other Red Hat and derived Linux distribution.

Install Foreman-Proxy Using Ansible

Posted on April 22, 2022 by Marco Antonio Carcano

A Foreman proxy (that is the upstream software of the Red Hat Network Satellite Server 6 Capsules) is a server that mirrors the contents from Katello. It's primary aim is to facilitate content federation across various geographical locations, but it is often used to:

decrease the load on the central Katello server
reduce bandwidth usage onto geographical links
increase redundancy, and also to achieve a fine grained segregation level that may be required by some regulatory

Unless you are working in a quite small and not geographically distributed environment, it is very likely that you must provision a Foreman proxy sooner or later.

Provisioning Foreman proxies, same way as installing software in general, is a typical time consuming and error prone task that is often convenient to automate in some way.

As we already saw in the previous post, we can install Foreman proxy using Ansible having it to:

ensure that the target systems meet the minimal requirements
automatically partition the systems in the most convenient way
install everything taking in account of using the right versions of the involved packages so as to avoid installation failure because of wrong dependencies
set up all the configurations that are required to improve the usability of the installed environment
take care of issuing all the necessary statements to configure a Foreman proxy (a Capsule) on Katello (the Satellite) and automatically provision it

This is the second part of the "Install Katello Using Ansible" post: we are about to see how the playbooks developed in that post can be used to easily install Foreman-proxy using Ansible.