Blog posts about DevOps, infrastructure, and software engineeringhttps://tasnimzotder.com/https://tasnimzotder.com/posts/how-large-language-models-work/https://tasnimzotder.com/posts/how-large-language-models-work/I use LLMs every day but couldn't reason about them. So I dug in — from the SRE angle. Here's the system, the bottlenecks, and what an infra person should care about.Sun, 03 May 2026 00:00:00 GMThttps://tasnimzotder.com/posts/writing-a-basic-dns-server/https://tasnimzotder.com/posts/writing-a-basic-dns-server/In one of my SRE interviews, I was asked to write a basic DNS server. I knew DNS resolves names to IPs, but I'd never looked at the actual wire format. I froze. So I went home and built one from scratch — UDP listener, binary parser, response builder — all in about 150 lines of Go.Thu, 05 Mar 2026 00:00:00 GMThttps://tasnimzotder.com/posts/container-isolation-misconceptions/https://tasnimzotder.com/posts/container-isolation-misconceptions/I thought I understood container isolation. Then I ran a few experiments on a live Docker host and found that --pid=host exposes everything, killing docker run does nothing, and malloc() lies about memory limits.Tue, 17 Feb 2026 00:00:00 GMThttps://tasnimzotder.com/posts/alb-consolidation-cutting-aws-load-balancer-costs-by-80-percent/https://tasnimzotder.com/posts/alb-consolidation-cutting-aws-load-balancer-costs-by-80-percent/We had 250+ services on AWS ECS, each with its own Application Load Balancer. The bill was absurd. I helped build cluster-level ALB consolidation into our open-source ECS deployment tool, and the change was merged upstream.Sun, 08 Feb 2026 00:00:00 GMThttps://tasnimzotder.com/posts/go-concurrency-patterns/https://tasnimzotder.com/posts/go-concurrency-patterns/I've been writing Go professionally for a while now, and concurrency is the feature that keeps pulling me deeper. Here's a catalog of patterns I've learned, used, and sometimes gotten wrong.Sat, 19 Apr 2025 00:00:00 GMThttps://tasnimzotder.com/posts/setting-up-samba-on-raspberry-pi/https://tasnimzotder.com/posts/setting-up-samba-on-raspberry-pi/I wanted a simple way to share files across my devices at home, so I turned a Raspberry Pi 5 into a NAS using Samba. Here's how it went, including some benchmarks.Sat, 11 Jan 2025 00:00:00 GMThttps://tasnimzotder.com/posts/setting-up-a-point-to-point-wireguard-vpn-server-on-raspberry-pi/https://tasnimzotder.com/posts/setting-up-a-point-to-point-wireguard-vpn-server-on-raspberry-pi/I wanted to securely access my Raspberry Pi from outside my home network, so I set up a WireGuard VPN tunnel. Turns out it's surprisingly simple - here's how I got it working.Sun, 01 Sep 2024 00:00:00 GMThttps://tasnimzotder.com/posts/open-media-vault-setup-raspberry-pi/https://tasnimzotder.com/posts/open-media-vault-setup-raspberry-pi/NAS (Network Attached Storage) is a storage device that is connected to a network and allows storage and retrieval of data from a central location for authorized network users and varied clients. In this article, we will see how to setup a NAS using openmediavault on a Raspberry Pi 4.Thu, 15 Feb 2024 00:00:00 GMThttps://tasnimzotder.com/posts/optimizing-game-of-life-algorithm/https://tasnimzotder.com/posts/optimizing-game-of-life-algorithm/I got nerd-sniped by Conway's Game of Life and ended up spending a weekend squeezing performance out of it with bit packing and goroutines. Here's what I tried and how much faster it got.Sat, 16 Dec 2023 00:00:00 GMT