Igor Kupczyński

We’ve received customer reports of workers producing bursts of UNAVAILABLE: No connection established.

TL;DR # Two Cursor bugs bite when you nest git repos under a gitignored parent and open them in one window: Semantic search returns nothing when the .code-workspace lists the root folder (.) alongside its own nested subfolders.

A collection of load balancer surprises I’ve encountered.

A Vagrant-based sandbox for running AI coding agents in full autonomous mode—without risking your host machine.

The following incident is fictional, but the architecture lessons are real.

Hatchet is a durable task orchestration platform, built on PostgreSQL.

I recently reviewed a Go codebase that implemented connection limiting in a TCP proxy.

If you’re using AI coding agents—and who isn’t these days—you’ve probably noticed each tool wants its own configuration file.

I found this excellent article by Utkarsh Kanwat: Betting Against Agents.

I recently gave a talk at an internal Elastic conference about prompt engineering techniques in 2025, accompanied by live demonstrations using Mistral via Ollama, VS Code Copilot, and Windsurf.

I often change my default browser.

I came across an interesting article by Mai-Lan Tomsen Bukovec, AWS Vice President of Technology, about a framework for Principal Engineer roles.

Recently, I encountered a fascinating incident where some API endpoints received unexpected traffic.

I came across an interesting method called “Chain of Density” that promises to generate increasingly concise and information-rich summaries.

Paul Graham’s “Founder Mode” Paul Graham’s essay Founder Mode is doing the rounds in social media: In effect there are two different ways to run a company: founder mode and manager mode.

TIL S3 supports conditional writes Check out the official AWS announcement and the more detailed S3 Conditional requests guide.

Great book by the star CEO of Snowflake.

Go binaries are not inherently container-aware, specifically in that they do not account for memory and CPU limits.

Remember that Java slogan, Write once, run anywhere?

Bookmarks on salary negotiation: Classic from Patrick McKenzie Salary Negotiation: Make More Money, Be More Valued 101 on offer negotiation from Rishi Taparia Negotiating your startup job offer Other links in no particular order Ten Rules for Negotiating a

Use cases for Private Link and differences in its implementation across the major Cloud Providers.

Theory of constraints applied to IT operations.

How to find out a container responsible for a given open port on a host.

I’ve created a telegram bot to give me a daily updates to a webpage I was tracking.

This post has a companion github repo github.com/igor-kupczynski/remote-debug-example – check the repo for a simple example.

Natural project planning is a project planning method described by David Allen in his bestseller Getting Things Done.

Updated: 2022-09-29.

I’ve read Zero to One: Notes on Startups, or How to Build the Future by Peter Thiel.

How to build a great engineering organization — advice from Elastic’s SVP Engineering.

How to setup Server Name Indication with Traefik.

How to improve any process.

In the previous post, we’ve presented an AWS Lambda function to automatically invalidate resources in CloudFront distribution when underlying objects in an S3 bucket change.

One of the VPNs I connect to sets the DNS server for the link.

There are only two hard things in Computer Science: cache invalidation and naming things. – Phil Karlton In this post we will focus on cache invalidation.

Today I’ve rediscovered Fire and Motion blogpost by Joel Spolsky.

The procedure changed on recent ubuntu compared to what I used to do.

After a upgrade from 18.04 my external monitor stopped working.

I’ve got a legacy windows app that I need to run from time to time.

How to minitor health of SSD drives, case study on my failed Kingston SUV500MS480G.

Back to Linux after almost 3 year hiatus.

Fix annoying issues with Zoom and HiDPI on Kubuntu 18.04.

Notes I’ve took while doing a microbenchmark of some code.

Classic advice on time management.

This post describes how to enable Class Data Sharing (CDS) for a java app and what are the benefits of doing so.

Conference notes.

I just don’t grok the vi (yet).

I’ve read 12 Rules for Life: An Antidote to Chaos by Jordan Peterson.

Talk about career options for pupils of my old highschool I was asked to do a short talk on the career options in IT for Henryk Sienkiewicz grammar school.

Some of my coworkers use Eshell inside emacs as their main terminal emulator.

I’ve recently read Insanely Simple: The Obsession That Drives Apple Success by Ken Segall.