I'd like to propose that the Mesos 1.3.0 should not allow pre-1.0 Mesos agents to register.
Motivation: (1) We can simplify the master code in a few places. For example, we can assume that we always have a FrameworkInfo for any task running on a registered agent. Needing to handle running tasks without a FrameworkInfo makes the code unreadable and has been a source of bugs. (2) The master only needs to report "orphan tasks" and "unregistered frameworks" if the cluster contains pre-1.0 agents. If we disallow such agents, we can remove the code for computing these fields in the HTTP endpoints and elsewhere. (We'll probably still need to keep the actual fields in the JSON/protobuf output for backward compatibility, but they will always be empty.) We can also remove "orphan tasks" from the web UI. In addition to declaring that Mesos 1.3.0 masters will not support pre-1.0 Mesos agents in the CHANGELOG, it seems safer to me to disallow such agents from registering. Comments welcome. Thanks, Neil
