Last year there was a discussion whether delta rpms should be activated or not by default in the Fedora 22 distribution, whether this feature should be kept or simply removed. But do you know exactly what delta rpms are? How…

Sometimes to get some entropy you have to do strange things. Do you remember to make sudden mouse movements during SSH keys generation? Where do this entropy come from? Why does everything sometimes seem stopped? How does it work for…

At first, managing package groups seems easy. Package groups are a simple means to gather packages under a unique name. But, it’s not so simple! There are different types of package groups. There are at least two ways to call…

It’s now two years that this website exists. New tutorials have regularly been added. Lots of tutorials have seen their content increased through the “Additional Resources” section to provide advanced material to hungry readers. Besides learning new topics, keep an…

Until recently, SSL certificates were so expensive that you couldn’t set up your personal website only for fun. You had to have a good reason or a big wallet. This is not the case anymore. Now and until the letsencrypt.org…

If you use KVM for managing your virtual machines, you can sometimes run out of space in the /var/lib/libvirt/images directory, the default location for the RHEL/CentOS distributions. Because KVM knows the concept of thin provisioning through the qcow2 image format, the…

During the RHCSA exam, you need to go fast. When dealing with partition creation, you can’t afford to waste time, searching for information about the current configuration with almost obsolete command like fdisk -l displaying a very cryptic and mostly…

With the upcoming RHEL 7.2 version, Systemd should be upgraded, going from version 208 to 219. This Systemd upgrade decision was taken according to Lukáš Nykrýn from Red Hat because “it is really difficult and risky to backport patches from newer version…

Here are some of the main 2015 Red Hat Summit announcements: the upcoming RHEL 7.2 release will bring SCAP profiles into the installation process, cryptography enhancements, kernel patching, performance gains (network and system), a new predictable cycle for software updates,…

The other day I was looking at some Systemd service properties with the systemctl show command. One of them, CPUShares, got my interest. Caution: The following tutorial shouldn’t be run on a production server! The CPU will be used at…