Product Engineering
Detect Git branch state without breaking in detached HEAD
Replace brittle parsing with Git plumbing, distinguish branch, detached, unborn, and invalid states, and keep release automation recoverable.
Read note →FIELD NOTES
Practical technology,
explained like a conversation.
Tutorials, operational lessons and verified industry developments from the point where infrastructure, security and software meet.
152published notes
Tech News
AWS WAF labels gain dynamic interpolation
Published 2026-07-21. This is a sourced Emmanuel Corels field briefing, written for builders who need the operational meaning behind the headline.What was actually announcedAWS published dynamic label interp…
Read note →Cloud & DevOps
Validate environment drift
Before touching configuration, we will turn the symptom into a precise question and collect a baseline that can be compared after the work.Our specific objective is validate environment drift. A drift check …
Read note →Networking & ISP Systems
Trace DNS answers from the authority
This walkthrough is for the moment when you need an answer you can defend, not another command copied from a forum.Our specific objective is trace dns answers from the authority. Follow delegation step by st…
Read note →Automation & Scripting
Write idempotent Ansible tasks
This is a practical operator’s guide: establish context, run the smallest useful check, interpret it correctly, and leave a clean recovery path.Our specific objective is write idempotent ansible tasks. Check…
Read note →Databases & Reliability
Remove duplicate PostgreSQL rows—and stop them returning
Define duplicate identity, choose a deterministic survivor, archive and delete extras in controlled batches, then enforce the rule with a unique index.
Read note →Cybersecurity
Create a self-signed localhost certificate with correct SANs
Generate a short-lived local TLS certificate, include every DNS/IP identity, protect the private key, establish trust deliberately and verify hostname plus chain.
Read note →Web Infrastructure
Check upstream timing in Nginx
This is a practical operator’s guide: establish context, run the smallest useful check, interpret it correctly, and leave a clean recovery path.Our specific objective is check upstream timing in nginx. Separ…
Read note →Linux & Server Operations
Make directory-dependent Bash jobs safe around missing paths and symlinks
Turn a familiar directory check into a reliable operational pattern: quote paths, distinguish links, create atomically, validate ownership, and test failure paths.
Read note →Containers & Kubernetes
Read a failing pod in the right order
This walkthrough is for the moment when you need an answer you can defend, not another command copied from a forum.Our specific objective is read a failing pod in the right order. Events explain scheduling a…
Read note →Product Engineering
Write a migration rollback note
When this problem appears in production, urgency encourages guessing. The procedure below deliberately slows the first minute down so the next thirty are useful.Our specific objective is write a migration ro…
Read note →Tech News
Gemini 3.6 Flash becomes available in GitHub Copilot
Published 2026-07-21. This is a sourced Emmanuel Corels field briefing, written for builders who need the operational meaning behind the headline.What was actually announcedGitHub added Gemini 3.6 Flash to t…
Read note →Page 2 of 13 · 152 posts