Flatcar: Learning from the Flatcar DNS Outage – A Post-Mortem
On February 2nd and 3rd, 2025, Flatcar experienced a significant DNS outage that affected our update and release servers, as well as parts of our CI/CD infrastructure. As a result, users were unable to download new Flatcar releases, retrieve Flatcar images for several hours. The root cause was a miscommunication during a domain transfer, which led to DNS mis-configurations. In collaboration with the Linux Foundation (LF) IT team, we have conducted a full post-mortem analysis to understand the issue, improve our processes, and ensure greater reliability for the Flatcar community moving forward.