Posts

Weihrauch HW 77 K pellet comparision

This is gonna be a very unusual post, in some ways it is still about technology even if it is not about the usual IT stuff I write of. I have a Weihrauch HW 77 K spring air rifle I mostly use to shoot in my backyard or terrace. When it comes to air guns I always have troubles finding proper reviews and comparisons online, so I figure it might be worth sharing my findings here. …

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New Gohugo theme

Since I apparently got recurring readers (no, for real, I do) I suspect someone might actually have noticed how the look of the blog changed drastically a few weeks ago. To explain what happened a bit of backstory is required; this blog is built using a static website generator called Gohugo, the way it works is basically the following: choose or build a theme from scratch. Write some articles in Markdown or some other memetic markup language. …

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Kubernetes cluster for manufacturing engineering: tale of an epic commissioning

- Introduction A quite big company that produces parts for some of the most important automotive industry companies was interested in a cloud-based system to monitor the overall efficiency of their production machines, analyze some key parameters and optimize the production activities scheduling. Goal of the project was to connect eleven industrial manufacturing machines to the cloud, extract specific machine data and develop a web application for the visualization and management of such data, while guaranteeing information confidentiality and security. …

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FreeBSD, Nginx and htpasswd file generation

On most Linux distros it is possible to generate the htpasswd file entries simply using the htpasswd command line util. On FreeBSD the easiest way to accomplish the same task is using OpenSSL itself: openssl passwd -apr1 Enter the password twice to get a nice hash, copy that in the htpasswd file with the usual user:password_hash syntax.

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Disable head parking Western Digital drives

Most Western Digital hard drives’ firmware let the heads park themselves after a certain amount of seconds in case the disk is not actively performing any operation. This might be useful to keep power consumption under control but is actually harmful for disks that run 24/7 (WD Red for example). Luckily there is a way to disable head parking, this can be done directly from Linux using a tool called idle3ctl. …

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FreeBSD, NGINX and TLSv1.3

After a six months hiatus here is a new blogpost. This saturday I finally found the time to upgrade the configuration of the server that hosts this very website. Software stack is pretty simple: FreeBSD (version 12.0-p6),nginx (version 1.15.10) and OpenSSL (version 1.1.1a-freebsd). Install the required software: $ pkg install nginx-devel py36-certbot Get a SSL certificate from letsencrypt: $ certbot-3.6 certonly --standalone -d domain.tld -d www.domain.tld Certfiles location is /usr/local/etc/letsencrypt/live/<domain. …

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qemu/KVM PCI passthrough

PCI passthrough is the process of attaching a PCI-E device directly to a VM; CPU support (namely VT-D for Intel and AMD-V for AMD) and motherboard support (IOMMU) are required for PCI passthrough to work properly. Hardware configuration used: AMD Ryzen 1700x Gigabyte X370 K7 Nvidia Geforce GTX260 32 GiB of RAM and a few HDDs Fedora 29 as host OS The system only has a single graphic card because it is normally used as headless compute server for which a GPU is not really required; the graphic card is also very very old Nvidia Geforce GTX260 with a standard non UEFI BIOS. …

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Remotely unlock a full disk encrypted Fedora/CentOS server

The idea here is to be able to power on and unlock a remote Full Disk Encrypted (FDE from now on) server. I will leave the how “remotely power on” to the reader to figure out and focus on the other part. The easiest way to accomplish it is by using a program called: dracut-crypt-ssh. $ yum install dropbear dracut dracut-network openssh libblkid-devel gcc $ git clone https://github.com/dracut-crypt-ssh/dracut-crypt-ssh.git $ cd dracut-crypt-ssh $ . …

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