Dev-Ops is a methodology aimed to speed-up application development and release aimed at promoting

fast development methodologies – Development teams
fast quality assurance methodologies – QA teams
fast deployment methodologies – System Operators teams
iteration and continuous feedback – Project Management teams

The aim is to achieve a faster time to market.

DevOps inherits Agile methods such as SCRUM Project Management, but it is more focused on the tools necessary to achieve the goal. It is also possible to involve the Security delegating some rights to the other teams: this approach is called DevSecOps.

These tools Devops brings with it were previously confined into the development field only, such as Source Code Management tools like GIT, branching models such as GitFlow, Continuous Integration and Continuous Delivery tools such as Jenkins or Drone, schedulers such ad dKron, scanners for code quality and compliance such as SonarQube.

This means that professional of every fields, even system engineers and administrators, should have an understanding of these tools and models.

Enable And Configure Ansible On Red Hat Network Satellite

Posted on March 8, 2022November 14, 2024 by Marco Antonio Carcano

Red Hat Network Satellite Server 6, as well as its upstream project Katello, enables you to easily manage the registered client hosts using Ansible.

Conversely from Puppet, that requires the client to install the agent package and to be registered to the Puppet master running on the Satellite or Capsule, Ansible does not require installing anything client side, since it relies on SSH or, to tell it in Red Hat Network Satellite 6 terms, it relies on remote execution with SSH. The only thing that is required to manage the client hosts of the Satellite using Ansible is enable and configure remote execution and the Ansible plugin on the Satellite itself and on any Capsule you want to use.

This post shows you how to enable both remote execution with SSH and the Ansible plugin on the Satellite. To ensure that everything is properly working, we also run the ansible ping module.

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.

Puppet agent on Red Hat Network Satellite Clients

Posted on February 26, 2022November 14, 2024 by Marco Antonio Carcano

Red Hat Network Satellite Server, as well as its upstream project Katello, enables you to easily manage the registered client hosts using Puppet: for this to work, you must first install the Puppet agent on the client host and register it to the Puppet master instance that is running on the Satellite (or on the Capsule).

This post is a step by step guide that does not only show you how to install and configure the Puppet agent on the client host: it also thoroughly describe how to create the Puppet product on the Red Hat Network Satellite Server 6 (or Katello), add repositories for the relevant architecture families, assign them to the right Content View and publish them into the right Lifecycle Environment.

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.

Mind that configuration management using Puppet is the oldest way of managing registered hosts on Satellite: the current way is using Ansible. Red Hat announced Puppet deprecation by Red Hat Network Satellite Server 7.0 in 2020. For this reason my suggestion is to quickly migrate from Puppet to Ansible. If you want to learn more on using Ansible with Satellite, please read Enable And Configure Ansible On Red Hat Network Satellite.

Register Clients To Satellite Server 6 Or Katello

Posted on February 12, 2022November 14, 2024 by Marco Antonio Carcano

Red Hat Network Satellite Server 6, as well as its upstream project Katello, has been developed to provide software to client hosts, as well as manage their configuration sending SSH remote commands or leveraging on Puppet or Ansible.

The published packages are provided by the means of content views with frozen packages versions.

The obvious requirement to benefit from the provided services is registering client hosts. This post shows how to register clients on Red Hat Network Satellite Server 6 or Katello, providing all the necessary information to be skilled enough on subscription-manager to be able not only to operate it, but to successfully troubleshoot when it is not working as expected.

In addition to that, we also see how to enable and configure SSH based remote actions and how to run an existing Job Template..

YAML in a nutshell

Posted on November 21, 2021November 14, 2024 by Marco Antonio Carcano

YAML is a must-have skill for IT professionals, since it is probably becoming the the most commonly used document format for manifest and configuration files - think for example to Kubernetes, Ansible and a lot of other modern Dev-Ops oriented or CI/CD tools such as drone.

Being skilled on YAML does not only mean being able to write YAML documents, but also efficiently query and manipulate YAML files.

This post provides everything it is very likely you must know to exploit YAML in your daily work, explaining its syntax and showing things in action by using yq - a tool we can consider "the jq for YAML", and using Python with PyYAML.

By the way, this post is part of a trilogy of posts dedicated to markup and serialization formats, so be sure not to miss

JSON and jq in a nutshell

Posted on November 19, 2021November 14, 2024 by Marco Antonio Carcano

JSON is a must-have skill for IT professionals, since it is probably the most used document format when dealing with AJAX and with REST web-services: since both of them are broadly used on the web, it is very likely that sooner or later you'll ever have to deal with it.

Being skilled on JSON does not only mean being able to write JSON documents, but also knowing how to exploit tools such as jq to extract values or even a subset from a JSON document.

Having these skills makes your life easier not only if you are a developer, but also if you are involved in the system integration field.

This post is an overview about all you must know about JSON and how to work with it using jq.

By the way, this post is part of a trilogy of posts dedicated to markup and serialization formats, so be sure not to miss

XML in a nutshell

Posted on November 4, 2021November 14, 2024 by Marco Antonio Carcano

XML is a must-have skill for every professional: it is still broadly used by application protocols such as SOAP or SAML, or by description languages such as WSDL. By the way it is not something that is bound only to the application integration field: several applications relies on XML based configuration files and Blueprints, think for example to Apache Tomcat configuration files ("server.xml", "context.xml", ...), OSGI Blueprints such as a JAAS configuration, or again to Maven POM files or SCAP files (OVAL, XCCDF, ...).
The aim of this post is to provide a good overview of XML, explaining its goals, how to enforce it using schemas and generate a human-readable view of an XML file using XSLT.

The post also provides an overview of the XPath query language with some examples using the xpath command line tool. It shows you how to modify XML nodes and attributes using the xmlstarlet command line tool.

By the way, this post is part of a trilogy of posts dedicated to markup and serialization formats, so be sure not to miss

Of course these things would deserve a whole book, ... but as usual I try to be synthetic, showing you only the things that are really likely you'll sooner or later come across when working with XML, and giving tips on where to find more information on each topic.