Some commands you can walk back. Terminating an EC2 instance is not one of them. Day 14 paired a recoverable problem, a web server knocked over by a rogue process, with an unrecoverable one, deleting a server on purpose, and the contrast is the whole lesson. One Linux task, one AWS task. Track down the process blocking Apache and restore the service, then terminate an EC2 instance and confirm it is gone. The tasks come from the KodeKloud Engineer platform. httpd: diagnose in order, then restore When httpd will not start, resist the urge to guess. Work in order. Start with what the service itself reports: # What does httpd think is wrong systemctl status httpd systemctl start httpd The status output usually names the problem, and a failed bind on the port is the classic one. Before assuming a rogue process, check that httpd's own config is sane, because a wrong port or hostname produces the same "won't start" symptom: # Check the configured listen port and server name grep -i listen /etc/httpd/conf/httpd.conf vi /etc/httpd/conf/httpd.conf # Fix the ServerName directive if it is wrong: ServerName hostname:<port> If the config is fine and the port is genuinely taken, then you go hunting for the process holding it: # Find the PID on the conflicting port sudo su - yum install -y net-tools netstat -tulpn # Clear it, then bring httpd back kill -9 <PID> systemctl enable httpd systemctl start httpd systemctl status httpd kill -9 is SIGKILL, the instant, no-cleanup kill. It is the right tool when a process is wedged and ignoring a polite request, but as a default habit, it is worth trying a plain kill first. The order that matters here is diagnostic: config before process, gentle signal before forceful one. Rushing to kill -9 at the first sign of trouble is how you mask the real cause instead of fixing it. Terminating EC2: the command with no undo Day 9 was about protecting an instance from termination. Day 14 is the other side of that lever, actually terminating one, on purp

Just why? ʅ͡͡͡͡͡͡͡͡͡͡͡(̸̢̛̼̞̭͋ͅ)̸͚̰͛̔̾̀̿͒͂:̴͓̞̑̌̂̆̊͋̀:̸͎̟̯̂̓̌ ҉ ͡ ͞ ͞ ͞ ҉● ࿀ ● ࿀ ● ҉⃝ ⃝͢ ͞ ͘ ͞⃝̕ ͢ ̛ ⃝ ̸ ̡ ͢⃝̧ ͡ ͡ ̀ ̧ ̢⃝͜ ҉ ͞ ͞ ⃝͞ ͞ ͡⃝ ⃝҉҈҉҈҉҈҉҈҉҈҉ :̶̢͙͙͕̠̩͆(̷̮͍͚̫͚͂̍)̵̳̗̊( ̟̞̝̜̙̘̗̖҉̵̴̨̧̢̡̼̻̺̹̳̲̱̰̯̮̭̬̫̪̩̦̥ What am I supposed to do with this? It's un-Googleable. Unpronounceable. It doesn't even render the same way on various platforms. It looks one way on YouTube Music. Another on Apple Music. And yet another on Bandcamp. Even the artist name ⣎⡇ꉺლ༽இ•̛)ྀ◞ […]

Hi, I'm Cesar, a Senior Software Engineer with 10+ years of experience. In 2023, I got sick and...

GenPage is a generative AI system developed by Netflix to replace its traditional multi-stage recommendation pipeline by directly generating personalized user homepages. GenPage leverages user history and request context as a prompt to produce the entire page, resulting in improved user engagement and reduced serving latency. By Sergio De Simone

Following the success of its $99 Kodak-branded Snapic A1, Reto Project is releasing the Kodak EC35, an even more affordable 35mm film camera for just $34.99. The EC35 certainly isn't fancy. Its 25mm acrylic lens with a fixed f/10 aperture and 1/100 shutter speed basically put it on par with a drugstore disposable. The fact […]

On the latest episode of Equity, we debate whether Apple's lawsuit will cast over OpenAi's much-discussed plans to get into hardware and go public.

The spacecraft made a close approach to the red planet in May on its way to explore the asteroid it's named after.

When a new video shows up in one of our regional crawlers, three things need to happen almost immediately: the SQLite FTS5 search index for that region needs a new row, the discovery ranking cache needs to be invalidated, and the sitemap generator needs to know a URL was born. For a long time we did all of this inline, inside the same cron process that fetched the video. It worked until it didn't. A slow FTS5 rebuild would stall the fetch loop, a sitemap write would fail silently, and a crash halfway through meant one region had the video indexed and another didn't. The fetch and the fan-out were fused together, and every failure was a partial failure. The fix was to stop treating "a video was discovered" as a function call and start treating it as an event. At TrendVidStream we run discovery across 8 regions, and the moment we introduced NATS JetStream as the spine between the crawler and the downstream consumers, the whole system got calmer. This post is the concrete version of how we did it: the stream config, the publishers, the consumers, and the mistakes we made that you can skip. Why Not Just Use a Queue Table in SQLite We already had SQLite everywhere, so the obvious move was a jobs table. We tried it. The problems showed up fast: Polling latency vs. load tradeoff. Poll every second and you hammer the DB with mostly-empty SELECT queries across 8 regions. Poll every 30 seconds and your search index lags noticeably behind your crawler. No fan-out. One row, one worker. If the sitemap generator and the FTS5 indexer both need the same event, you either duplicate rows or invent a consumed_by bitmask. Both are ugly. Locking. SQLite's writer lock means the queue table and the actual data table start contending under the multi-region cron bursts we run. Cross-region delivery. Our regions aren't all on the same box. A queue table doesn't cross machines without you building a replication story on top. JetStream solves all four: push-based delivery (no polling), multipl

My Zero to Blockchain Engineer journey — Week 2 update Last week I announced I was teaching myself blockchain engineering from zero. This week I went deep into Cyfrin Updraft — and I have to be honest, it changed how I think about learning Web3. Here's everything I covered, what surprised me, and why I think this platform is the best free resource for anyone serious about becoming a blockchain developer. What I covered this week I'm currently 45% through the Blockchain Basics course on Cyfrin Updraft. Here's exactly what the lessons covered: Section 1 — What Is A Blockchain? This section answered the question properly — not in a surface-level way, but by starting with the problem blockchain solves. The lesson on centralized control hit differently. Think about it in a Nigerian context — banks freezing accounts, payment processors blocking transactions, elections where results can't be independently verified. These aren't hypothetical problems. They're things we live with. Blockchain's answer: a shared ledger where truth is verified by math, not by a middleman. That framing made everything click for me. Key lessons I completed: What Is A Blockchain — centralized problems vs decentralized solutions History Of Blockchain — from the double-spend problem to Bitcoin to Ethereum Benefits Of Blockchain — permissionless, immutable, credibly neutral Use Cases — DeFi, cross-border payments, DAOs, digital ownership Many Many Chains — L1s, L2s, Mainnets vs Testnets The Oracle Problem — why smart contracts can't access real-world data alone The Purpose Of Smart Contracts — math-based promises vs trust-based agreements What Is The EVM — Ethereum's computation engine explained simply Benefits Of Smart Contracts — decentralization, immutability, transparency Section 2 — Sending Transactions This is where things got hands-on — and where Cyfrin pulled ahead of every other platform I've tried. Key lessons: What Is A Wallet — your public address as a digital mailbox Setting Up A Wallet