MicroVMs
The Test That Only Failed When It Ran Second
A suite that passed alone and failed in the pipeline. The bug was not in the test, it was in what the previous job left behind on the runner.
Rohit Bhadani
I write about why software breaks and how people figure it out. Founder of Krova Cloud, building isolated microVMs on our own hypervisor. Years of Shopify theme work and shared hosting before that. If I have not reproduced it, I do not publish it.
Networking
Cloudflare 526: The Redirect Loop Behind One Setting
Flexible gives you an infinite redirect. Full strict gives you a 526. The documentation says Full or higher, and higher is the one that breaks.
Node.js
EMFILE: Too Many Open Files, and Why Raising ulimit Is Wrong
The quick fix is raising ulimit. The real question is what is holding thousands of descriptors open and never closing them.
MicroVMs
I Rebooted the VM and the Kernel Did Not Change
A patched kernel that kept reporting the old version after every reboot. The reboot was working perfectly. My assumption about where the kernel comes from…
Opinion
Five Things I Was Confidently Wrong About
Positions I argued for, sometimes loudly, that turned out to be mistaken. What changed my mind in each case.
Shopify
Shopify Webhooks You Are Not Receiving
The webhook is registered, orders are being created, and nothing arrives. Here is where they go and how to stop being unsubscribed.
Shopify
The Shopify Theme Debugging Toolkit
You cannot attach a debugger to Liquid. Here is the set of techniques that actually works for finding out why a theme is doing something unexpected.
Shopify
Migrating to Shopify Online Store 2.0 Without Breaking It
A practical migration order, the things that silently break, and how to verify you did not lose content along the way.
Shopify
Shopify Inventory Says In Stock and Checkout Says Otherwise
The storefront cached availability, the customer added to cart, and checkout disagreed. Here is where the state diverges and what to do about it.
Debugging
Your Error Messages Are a User Interface
An error message is read by a person under stress who needs to make a decision. Almost nobody designs them that way.
Bug Hunt
The Race Condition That Vanished When I Added Logging
The classic heisenbug. Here is why observation changed the outcome, and the three techniques that found it anyway.
Bug Hunt
The Outage Caused by a Successful Health Check
Every replica restarted at once during a brief database blip. The health check was working exactly as designed, and the design was wrong.