Category Archives: UNIX/Linux

Kubernetes: Pod resources.requests, resources.limits, and Linux cgroups

20 July 2025
 

 How exactly do resources.requests and resources.limits in a Kubernetes manifest works “under the hood”, and how exactly will Linux allocate and limit resources for containers? So, in Kubernetes for Pods, we can set two main parameters for CPU and Memory – the spec.containers.resources.requests and spec.containers.resources.limits fields: resources.requests: affects how and where a Pod will be… Read More »

TCP/IP: OSI and TCP/IP models, TCP packets, Linux sockets and ports

19 July 2025
 

  It’s difficult to describe in one post what thousands of books have been written about in a thousand pages, but today we’ll try to quickly review the basics of how hosts communicate on a network. First, let’s talk about the OSI and TCP/IP models, then about packet structure and connection establishment, and finally, we’ll… Read More »

Arch Linux: linux-firmware-nvidia: /usr/lib/firmware/nvidia/ exists in filesystem

9 July 2025
 

  Even though the changes were announced in emails from Arch Linux, for some reason, many people have had problems with the latest update: in the Arch Linux subreddits on Reddit, people are complaining like “Everything is broken, what should I do now?” Let’s see how to complete the upgrade and what exactly has changed.… Read More »

Pritunl: launching a VPN in AWS on EC2 with Terraform

23 June 2024
 

  I’ve already written a little about Pritunl before – Pritunl: Running a VPN in Kubernetes. Let’s return to this topic again, but this time on EC2 in AWS, without Kubernetes. So, what we need to do is to run some kind of VPN service for the project to have access to Kubernetes APIs/Kubernetes WorkerNodes/AWS… Read More »

Arch Linux: fixing the “yay: error while loading shared libraries: libalpm.so.13” error

17 March 2024
 

 After the latest Arch Linux upgrade, Yay reported the following error: yay: error while loading shared libraries: libalpm.so.13: cannot open shared object file: No such file or directory First, let’s check if we have the libalpm library file, and which version: $ sudo find / -type f -name “*.so*” | grep libalpm /usr/lib/libalpm.so.14.0.0 So, we… Read More »

Arch Linux: pacman – error “HTTP server doesn’t seem to support byte ranges”

30 May 2022
 

 During system upgrade with pacman -Syu, I got internet disruption, and on the next upgrade I got the error from pacman. It sounds like “HTTP server doesn’t seem to support byte ranges. Cannot resume“: [simterm] … ==> Retrieving sources… -> Downloading clightd-5.6.tar.gz… ** Resuming transfer from byte position 12288 % Total % Received % Xferd… Read More »