Kubernetes Through Control Theory Glasses — Part 1: HPAOne Saturday morning I was fixing my coffee grinder while watching James Hoffmann explain how a PID controller works in an espresso machine — using a ship navigation system as the example. Something cMay 13 · 18 min readdevgeist.hashnode.dev
Ordered Retries in Kafka: Why You Probably Shouldn't Build ThisI once spent three weeks in architectural meetings arguing that we should insert SQS between two Kafka topics. I wasn't doing it because I liked SQS. I was doing it because the "clean" Kafka-native reMar 24 · 9 min readdevgeist.hashnode.dev
Ordered Retries in Kafka: The Bugs You'll Find in ProductionIn Part 1, we introduced a "middle ground" for Kafka retries: when a message fails, lock its key, send the message to a retry topic, and let the main partition continue processing other keys. If you nMar 17 · 13 min readdevgeist.hashnode.dev
Ordered Retries in Kafka: Why The Retry Topic Is Breaking DownstreamI was on-call when the P1 hit. Slack lighting up, a downstream team's database rejecting writes. Constraint violations everywhere. I pulled up the logs. The events looked fine. The schema was correct.Mar 10 · 8 min readdevgeist.hashnode.dev
The Ghost in the Database: Why Is This Empty Table Taking 20 Seconds to Query?SELECT * FROM my_table; Query execution time: ~5 seconds Table rows: 0 This made absolutely no sense. A few years ago, I found myself staring at a performance metric that defied logic. We had a table Feb 3 · 8 min readdevgeist.hashnode.dev
