The system remained stable, the issue is now completely fixed.
Posted Apr 19, 2016 - 15:41 UTC
Monitoring
Build Queue is now depleted, new builds can start immediately again. We didn't see new errors related to this issue, and Google Cloud Status now marks the issue as resolved - we're still monitoring the system.
Posted Apr 19, 2016 - 15:07 UTC
Identified
We identified the problem: the authentication API we use for GCE had an accessibility issue. We're waiting for Google to fully resolve the issue, but right now it seems to be working reliably again. This issue is related to the now disclosed Google Cloud Platform incident: https://status.cloud.google.com/incident/appengine/16003
Android/Linux builds are now started properly, but the system goes through a significant build queue - build starts might be delayed. We're working on adding capacity to process the build queue as fast as we can.
Posted Apr 19, 2016 - 14:41 UTC
Investigating
Builds on the Android stack might not start right now - we're investigating