CoreOS offers three channels: alpha, beta, and stable. The idea is that when you deploy a CoreOS cluster, you run mostly stable instances but mix in some alpha/

CoreOS offers three channels: alpha, beta, and stable. The idea is that when you deploy a CoreOS cluster, you run mostly stable instances but mix in some alpha/beta instances as well. Automated updates always propagate from alpha to beta to stable, so if an auto-update would break your application(s) you would notice this on an alpha instance before it would hit your stable instances.