Reliability

We wanted to know what a maintenance window really costs a Magento store, against the alternative. Our deploy playbook takes one whenever a release has database work to do: every web server switches to the new code at once, the store shows its maintenance page while setup:upgrade runs, and then it comes back. The alternative is harder than it sounds. A rolling release, a canary or a zero-downtime deploy all need two versions of the code serving from one database at the same time, and Magento pushes back on that in three layers. It refuses pages when a module’s version doesn’t match the database. It refuses requests when the deployed configuration doesn’t match the imported one. And nothing at all protects a query that meets a schema it doesn’t match. A flag, deployment/blue_green/enabled, switches off the first two. Nothing switches off the third. ...

The last time I looked for a job was in 2018, that feels like a millennium ago. A full dark age ago. Things have changed a lot. AI and machine learning is no longer a nascent industry but one completely embedded in our lives. It was a massive shock for me to look for a job and find that the traditional way was… not the recommended way anymore. Yes, you can still count on your connections but getting through the door is more complicated than ever before. ...

Most monitoring systems tend to answer whether the server is up or not. All of that can be green while an ecommerce checkout is broken, the cart page could even respond 200s, while the add-to-cart button does nothing, and the graphs stay flat because nothing crashed. In November 2021 I wrote a little bot to answer the other question. Every five minutes it opens a real browser, searches for a product, adds it to the cart and loads checkout, and confirms that under the conditions at the time, checkout is up. ...