November’s availability overview
Two incidents in November caused notable disruption to GitHub’s issues, pull requests, and Actions services. The first was a certificate expiry that affected the web UI for roughly half an hour, followed later in the month by a MySQL replication issue that impacted Actions for over an hour.
Certificate expiry disrupts githubassets.com
On November 2 at 12:00 UTC, the SSL certificate for *.githubassets.com expired, breaking web requests that depend on GitHub’s UI and related services. An automated issue had flagged that the certificate was within 30 days of expiration, but the warning wasn’t acted on in time.
The impact was reported, and an on-call engineer resolved the problem quickly—the outage lasted 32 minutes. GitHub says it is reviewing its processes, tooling, and automation around certificate management to reduce the chance of a repeat.
Replication lag hits GitHub Actions
Later in the month, at 16:04 UTC on November 27, monitoring detected abnormally high replication lag in one of the MySQL clusters that supports GitHub Actions. The degraded state persisted for one hour and one minute.
Because the incident is recent, the investigation into contributing factors is still underway, and GitHub plans to share a more detailed breakdown in next month’s availability report.
GitHub continues to stress the importance of service reliability and user trust, and will keep posting updates on its efforts. More on engineering work can be found on the GitHub engineering blog.
