In November, we experienced two incidents resulting in significant impact and degraded state of availability for issues, pull requests, and GitHub Actions services.
The SSL certificate for *.githubassets.com expired, impacting web requests for GitHub.com UI and services. There was an auto-generated issue indicating the certificate was within 30 days of expiration, but it was not addressed in time. Impact was reported, and the on-call engineer remediated it promptly.
We are using this occurrence to evaluate our current processes, as well as our tooling and automation, within this area to reduce the likelihood of such instances in the future.
Our service monitors detected abnormal levels of replication lag within one of our MySQL clusters affecting the GitHub Actions service.
Due to the recency of this incident, we are still investigating the contributing factors and will provide a more detailed update in next month’s report.
We place great importance in the reliability of our services along with the trust that our users place in us every day. We’ll continue to keep you updated on the progress we’re making to ensure this. To learn more about what we’re working on, visit the GitHub engineering blog.