Category Archives: Linux

Find in Linux if your installed RAM is ECC

By | October 21, 2017

Sometimes really simple questions are hard to answer. One day I got the question from a coworker: “How do I know if some installed RAM is ECC or not”. The easiest way is to use dmidecode command that dumps in Linux all the system characteristics. But because I had no idea how to see if… Read More »

#Docker volumes and Selinux

By | September 30, 2017

When running complex environments on Docker on Linux again we face the mighty selinux. There are plenty of selinux alerts generated when I start my environment when the host machines have selinux enabled and volumes are used by the containers. Setting selinux permissions is hard and tedious and many people just prefer to disable it.… Read More »

Linux: Save a pdf presentation to individual image slides

By | May 26, 2017

There is a very simple way to save a pdf presentation to individual jpeg images of the slides using convert. convert -density 300 presentation.pdf presentation_page_%04d.jpg where: – density 300 specifies the DPI used to read the pdf. – presentation_page_%04d.jpg is a name pattern for the saved images As a result if presentation has 20 slides… Read More »

#DevOps the new hype at #DevTalks Cluj

By | May 20, 2017

It seems that now I have a name for what I have doing for the last 15 years 🙂 I attended a a DevTalks conference and the hype of the day was the DevOps idea. According to the wiki definition: DevOps (a clipped compound of “software DEVelopment” and “information technology OPerationS”) is a term used… Read More »

Linux Cluster with #DRBD replication: solving “HA LVM requires Only one logical volume per volume group” issue

By | April 24, 2017

I have a RHEL 6 Linux cluster setup where the main database storage is replicated on a remote site using DRBD. In case of a failure of the primary site the decision is taken to move operations on the remote site. When the production site is back online sometimes the administrator is too eager to… Read More »

Solving “HA LVM: Improper setup detected * initrd image needs to be newer than lvm.conf”

By | April 24, 2017

In a Linux HA cluster setup on RHEL 6 that involves replication between sites using DRBD suddenly after reboot of one of the nodes it was imposible to start any cluster service from that node. Surprinsingly there was no issue to do so from the other node. While looking in the /var/log/messages on the affected… Read More »

Quick fix for selinux issues caused by un-tagged files

By | April 5, 2017

Sometimes weird things happen when selinux is activated and files are un-tagged or policies are missing. Because I do not want to apply the usual stupid Internet advice: “disable selinux” I am trying to fix it if possible. Two simple steps to alleviate some of the “issues” caused by selinux. STEP 1: Generate SELinux policy… Read More »

Linux: Command line video editing

By | May 12, 2019

The best way to do simple video in Linux is using the command line. This way you can do quick one liner commands that do the job fast and clean. My favourite tool is ffmpeg. Install ffmpeg: If you do not have it already installed to install ffmpeg simply do (in Fedora): Install the rpmfusion… Read More »

Windows finally has an OS in it

By | January 17, 2017

Starting with build 1607 finally Windows 10 has a Linux in it. To enable the Linux user space (basically an Ubuntu) the following has to be done: STEP 1: Update Windows to 1607 Make sure you update Windows 10 to a build at least 1607. STEP 2: Activate developer mode Settings -> Updates & security… Read More »