The issue is resolved.
Jan 18, 10:24 PST
We have successfully launched additional resources for the Cybele (beta) stack. New builds should get picked up fine. Any builds that were pending on the faulty hardware have been marked as "error" so that future builds can get picked up. Errored builds can be re-run at any time.
Jan 18, 10:16 PST
The issue has been identified as a kernel panic on a few hosts. We are working to bring up additional hardware.
Jan 18, 09:17 PST
We have identified an issue with the Cybele (beta) stack which is preventing some builds from completing normally. We are looking into the issue.
Jan 18, 09:16 PST